Innovative Ship and Offshore Plant Design

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(1)2019-07-22. Lecture Note of Innovative Ship and Offshore Plant Design. Innovative Ship and Offshore Plant Design Part I. Ship Design Ch. 7 Propeller and Main Engine Selection. Spring 2019. Myung-Il Roh Department of Naval Architecture and Ocean Engineering Seoul National University Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 1. Contents  Ch. 1 Introduction to Ship Design  Ch. 2 Design Equations  Ch. 3 Design Model  Ch. 4 Deadweight Carrier and Volume Carrier  Ch. 5 Freeboard Calculation  Ch. 6 Resistance Prediction  Ch. 7 Propeller and Main Engine Selection  Ch. 8 Hull Form Design  Ch. 9 General Arrangement (G/A) Design  Ch. 10 Structural Design  Ch. 11 Outfitting Design. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 2. 1. (2) 2019-07-22. Ch. 7 Propeller and Main Engine Selection. 1. Characteristics of Propeller 2. Characteristics of Diesel Engine 3. Procedure of the Determination of Propeller Principal Dimensions and Main Engine Selection. 3. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Review] Resistance, Power Estimation - Power Prediction of Main Engine ① EHP (Effective Horse Power). Ship speed (Vs) Total calm-water resistance (RT(v)). EHP  RT (v)  v. (In Calm Water). ② DHP (Delivered Horse Power) (  D : Propulsive efficiency). DHP . EHP. D  O H R. O: Open water efficiency  H : Hull efficiency  R: Relative rotative efficiency. D. ③ BHP (Brake Horse Power). BHP . DHP. DHP. T. (. T : Transmission efficiency). ④ NCR (Normal Continuous Rating). NCR  BHP(1 . Propeller Shaft. Sea Margine ) 100. ⑤ DMCR (Derated Maximum Continuous Rating). Propeller. BHP. Main Engine. DMCR . NCR Engine Margin. ⑥ NMCR (Nominal Maximum Continuous Rating). NMCR . DMCR Derating rate. * R: The ratio between a propeller's efficiency attached to a ship (O,B) and in open water (O), that is, R = O,B /O = QO/QO,B Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 4. 2. (3) 2019-07-22. Example of a Diesel Engine and Propeller. Funnel. Diesel generator Shaft Propeller. Main engine. * Reference: Korea Scientific Models Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 5. 1. Characteristics of Propeller. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 6. 3. (4) 2019-07-22. Example of a Propeller      . Ship: 4,900 TEU Container Ship Owner: NYK, Japan Shipyard: HHI (2007.7.20) Diameter: 8.3 m Weight: 83.3 ton No of Blades: 5. 7. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Concept of the Determination of Principal Dimensions of a Propeller. Wheel design to draw the carriage with cargo by one horse for maximum speed Given. Find. One Horse = Main Engine. Wheel Design = Propeller Design. Frictional Force of Wheels = Resistance of a Ship. Maximum Speed = Maximum Speed of a Ship. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Wheel Diameter = Principal Dimensions of a Propeller. 8. 4. (5) 2019-07-22. Propeller Components. Direction of Rotation. Trailing Edge Leading Edge Fillet Area Hub. Shaft. Cap Back (Suction Side) Face (Pressure Side) 9. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Principal Dimensions of a Propeller (1/4)  Diameter. Diameter. Back (low pressure). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Face (high pressure). 10. 5. (6) 2019-07-22. Principal Dimensions of a Propeller (2/4)  Pitch (Pi): Movement forward for one turn of the propeller  One turn of the screw results in a movement forward which corresponds to the screw’s pitch.  Similarly, the propeller has a pitch which can be regarded as the angle of the propeller blades (pitch angle).  Sometimes, the ratio of pitch and diameter (Pi/DP) can be used instead of the pitch.. Pitch angle. 11. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Principal Dimensions of a Propeller (3/4)  Expanded Area Ratio (AE/AO)  The ratio of the expanded area (AE) and the swept area (AO)  The smaller ratio is, the higher possibility of cavitation is. The minimum value of the ratio should be given for cavitation-free.. or Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 12. 6. (7) 2019-07-22. [Reference] Blade Area Ratio (BAR) (1/2)  Projected Area Ratio (PAR)  It is the area of the outline as projected onto a surface below. Projected area ratio is the smallest of the three..  Developed Area Ratio (DAR)  It is the area of the blade outline if it could be untwisted (i.e., as if the whole blade were unattached from the hub and brought to zero pitch)..  Expanded Area Ratio (EAR)  It is what if the developed area could be flexibly unwrapped on a flat surface so that all sections were parallel. It is what is important to propeller designers, to treat the propeller blade like a wing. In other words, the expanded view converts the propeller from its helix to a flat plane. EAR is typically close in magnitude to DAR, and is often used interchangeably.. 13. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Reference] Blade Area Ratio (BAR) (2/2) Projected area. Developed area. Expanded area. Conversion between each other. P PAR  1.067  0.229  i DAR DP EAR DAR    0.34  2.75   DAR Z   Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. PAR becomes small if Pi/DP becomes large. PAR  DAR  EAR (PAR < DAR < EAR) Thus, high Pi/Dp and small PAR result in high possibility of cavitation. 14. 7. (8) 2019-07-22. Principal Dimensions of a Propeller (4/4)  Ship Speed (Vs)  Ship speed at which the propeller efficiency (O) is to maximized.  Actually, this speed can be different from the service speed (Vs) required by ship owner.  The ideal case is that this speed is equal to the service speed (Vs).. 15. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Reference] Advance Speed and Advance Ratio The difference between the propeller’s pitch and the real movement is called slip and is necessary in order for the blades to grip and set the water in motion. This means that when the propeller has rotated one turn in the water it has only advanced part of the pitch (usually in the order of 75~95 %). At the same time, the ship will drag water with it, somewhat in front of the propeller. The water’s speed reduction which can be 5~15% for pleasure boats is called ”wake” and affects the measured value of the slip. Advance speed: Speed of advance per unit of time, typically the water speed of the ship. Advance ratio: The ratio between the distance the propeller moves forward through the fluid during one revolution, and the diameter of the propeller.   .  . Advance Speed. VA  Vs  (1  w) Advance Ratio. VA  (1 / n) DP VA  n  DP. J. Ship speed. 0.7R. where, w: wake fraction Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 16. 8. (9) 2019-07-22. Propeller Open Water (POW) Test  This test is carried out under ideal condition in which the propeller does not get disturbed by the hull.  Given: Propeller Dimensions (DP, Pi, AE/AO, z), Propeller RPM (n), Speed of Advance (VA)  Find: Thrust (KT), Torque (KQ), Propeller Efficiency (o) for Advance Ratio (J). Uniform flow (VA). * R: The ratio between a propeller's efficiency attached to a ship (O,B) and in open water (O), that is, R = O,B /O Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 17. Towing Tank Test. POW test (J, KT, KQ, O) Self-propulsion test (TM, QM, nM). Propulsive coefficient of model. Ship power and RPM DHP = cP  DHPS nP = cn  nPS. Resistance test (RTM). Scale effect on t, w, R. Scale effect on propeller (DHPS, nPS). Propulsive coefficient of ship. Model-ship correlation (cP, cn). * R: The ratio between a propeller's efficiency attached to a ship (O,B) and in open water (O), that is, R = O,B /O Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 18. 9. (10) 2019-07-22. Main Non-dimensional Coefficients of Propeller From dimensional analysis: ① Thrust coefficient:. ② Torque coefficient:. ③ Advance ratio:. ④ Propeller efficiency:. T  KT   n  DP 4 2. Vs: Ship speed [m/s] w : Wake fraction T : Thrust of the propeller [kN] Q : Torque absorbed by propeller [kN·m] n : Number of revolutions [1/s]. Q  KQ   n 2  DP 5. VA n  DP VA  Vs  (1  w) J. o . (in open water). J KT  2 K Q. DP : Propeller diameter [m] Pi : Propeller pitch [m] VA : Speed of advance [m/s]. . : Density of sea water (1,025) [kg/m3]. * Thrust deduction coefficient: The ratio of the resistance increase due to rotating of a propeller at after body of ship Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 19. Propeller Efficiency (O)  Efficiency of a propeller itself.  One of components of propulsive efficiency (D). o . DHP . EHP. D. J KT  2 K Q. (  D : Propulsive efficiency). D  O H R O : Open water efficiency  H : Hull efficiency  R : Relative rotative efficiency. Output loses for propeller. EHP DHP. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 20. 10. (11) 2019-07-22. POW Propeller Model. Actual Propeller. Model Propeller. Geometric Similarity. T.   n 2  DP 4 Q.   n 2  DP 5.  KT  KQ. VA n  DP VA  Vs  (1  w). Same non-dimensional coefficients. J. K. T. , KQ , J . 21. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Propeller Open Water (POW) Curve  Values of KT, KQ, and O at different pitch ratio (Pi/DP). KT . T   n  DP 4. KQ . Q   n 2  DP 5. J. o . 2. VA n  DP. J KT  2 K Q. J Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 22. 11. (12) 2019-07-22. Propeller Regression Polynomials for POW Curve  Regression Polynomial Function of Advance Ratio, Pitch Ratio, Expanded Area Ratio, No. of Blades. KT and KQ  Cs,t ,u, v ( J )s (Pi / DP )t ( AE / AO )u z v KQ. KT. s t u (J) (P/DP) ( AE / Ao ). Cs , t , u , v. v C s,t ,u ,v (z). s t u v (J) (P/DP) ( AE / Ao ) (z). +0.00880496 -0.204554 +0.166351 +0.158114 -0.147581 -0.481497. 0 1 0 0 2 0. 0 0 1 2 0 1. 0 0 0 0 1 1. 0 0 0 0 0 0. +0.00379368 +0.00886523 -0.032241 +0.00344778 -0.0408811 -0.108009. 0 2 1 0 0 1. 0 0 1 2 1 1. 0 0 0 0 1 1. 0 0 0 0 0 0. ⋮. ⋮. ⋮. ⋮. ⋮. ⋮. ⋮. ⋮. ⋮. ⋮ 23. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Forces Acting on Propeller Trailing edge. L: Lift force D: Drag force T: Thrust Q: Torque. Leading edge. Q T. L. Back Face. T (Suction side) Back. Trailing edge. Leading edge. VA VT = (RPM/60)DP. Q D. Propeller Open Water Efficiency = Face (Pressure side). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Distance per unit time (Speed). TVA 2(RPM/60)Q Rotation angle per unit time. 24. 12. (13) 2019-07-22. Hull Vibration Due to Propeller Rotation. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 25. Pressure on Hull Due to Propeller Rotation. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 26. 13. (14) 2019-07-22. Cavitation  Cavities (small liquid-free zones, “bubble”) are generated by the phase change of water from liquid to gas due to not temperature change but pressure change, that is, rapid change of pressure around blades of propeller.  Noise and vibration problem, Corrosion at the back of blades Pressure. High speed. Pressure drop. Liquid. Separation of air in water. Streamline. Solid. Cavitation. Pressure Cavity (bubbles). Gas. Vapor pressure. Temperature. Cavity. Explosion Back. Propeller blade. Streamline. Face. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 27. 2. Characteristics of Diesel Engine. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 28. 14. (15) 2019-07-22. Example of a Main Diesel Engine of Ship. 29. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Crank Shaft in the Maine Engine  Device to translate linear piston motion into rotation  BHP (Brake Horse Power): Power which is delivered to crank shaft from the main engine. Crank shaft for 6-cylinder marine diesel engine Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 30. 15. (16) 2019-07-22. Characteristics of Diesel Engine  Brake Horse Power (BHP) of Diesel Engine. BHP  Pme  L  A  n  Z Where,. Power. BHP: Brake Horse Power(kW) Pme : Mean Effective Presure (kN / m2 ) L : Piston Stroke (m) A : Piston Cross-Sectional Area ( m 2 ) n : Number of Revolutions (1/ s) Z : Number of Cylinder. Engine speed (rpm). If A and Z are constant, min = 75% max. BHP  C DE  Pme  n. max. Therefore, brake horse power “BHP” of a diesel engine is proportional to the rpm “n” and mean effective pressure “Pme”. 31. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Diesel Engine Layout Diagram Logarithmic Scale. Power. NMCR: Maximum power/speed combination of the chosen engine. This is the criterion of engine size, weight and price. L1: NMCR(Nominal Maximum Continuous Rating). = NMCR. Engine speed (rpm) min. max. The NMCR point is the upper right corner of the layout diagram. In the case of MAN/B&W engine, the NMCR point refers to L1. And in the case of Waertsilae (Sulzer) engine, R1 refers to this point.. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Power of Diesel Engine is described by the straight line (Slope of the straight line : 1). 32. 16. (17) 2019-07-22. Engine Type Identification of MAN/B&W* Diesel Engine. : bore. * Currently, MAN Diesel & Turbo. 33. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. MAN/B&W Diesel Engine (1/2) Reference: MAN/B&W, Two-stroke Engines MC Program, 1996. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 34. 17. (18) 2019-07-22. MAN/B&W Diesel Engine (2/2) Reference: MAN/B&W, Two-stroke Engines MC Program, 2007 http://www.manbw.com/engines/TwoStrokeLowSpeedPropEnginesProgram.asp. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 35. MAN/B&W Two Stroke Low Speed Diesel Engine - S80MC6 Engine Example) S80MC6 Engine: Bore 800 mm, Stroke 3,056 mm. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 36. 18. (19) 2019-07-22. MAN/B&W Two Stroke Low Speed Diesel Engine - S80MC6 Engine. 37. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Matching the Powers and RPMs of Propeller and Diesel Engine Output Power of a Diesel Engine. Power Absorbed by a Propeller. PD.E .  Pme  A  L  n  Z. Pprop.  2  n 3  DP  KQ  c3  n 3. P. 5. Diesel Engine. Propeller. n Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 38. 19. (20) 2019-07-22. Sea Margin  If the weather is bad, the resistance will increase compared to that at calm weather conditions. When the necessary engine power is to be determined, it is therefore normal to add an extra power margin.  Sea margin is not an exact value, but usually expressed by the additional margin determined by shipyard or owner. The so-called sea margin is about 15~20% of the power at calm water.  Note: Light running propeller (increase of propeller rpm) refers to the margin of propeller rpm.  Light running propeller margin (RPM margin)  MAN/B&W Engine: 2.5~5.0%  Waertsilae (Sulzer) Engine: 3.5~5.3%. 39. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. NCR, Engine Margin, DMCR  The normal continuous rating (NCR) is the power at which the engine is normally assumed to operate.  The owner prefers that engine is operated continuously at maximum 85~90% of DMCR to get the margin of speed. DMCR . Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. NCR Engine Margin. 40. 20. (21) 2019-07-22. [Appendix] Thermal Efficiency According to Engine Type. * Reference: MAN B&W, Two-stroke Low Speed Diesel Engines for Independent Power Producers and Captive Power Plants, 2009 Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 41. 3. Procedure of the Determination of Propeller Principal Dimensions and Main Engine Selection. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 42. 21. (22) 2019-07-22. Procedure of the Determination of Propeller Principal Dimensions and Main Engine Selection Requirements of Design ship. Basis Ship. Determination of Principal Dimensions and Cb, Lcb, Cm, Vs(Fn). Principal Dimensions and Cb, Lcb, Cm, Vs of the Basis Ship. Estimation of Resistance and Propulsion Power based on Empirical Methods, for example, Holtrop & Mennen (Cw, k, w, t, R). Prediction of Resistance and Propulsion Power in Calm Water Based on the Model Test (Cw, k, w, t, R). Prediction of Resistance and Propulsion Power by Applying Correction Factor. Estimation of Resistance and Propulsion Power Based on Empirical Methods, for example, Holtrop & Mennen Correction Factor Calculation from Model Test Result and Empirical Method. Assume the Diesel Engine Power and Speed (RPS) Determination of the Main Engine Power (P) and Speed (n), and Propeller Pitch (Pi). Stage 0 Assume the Propeller Diameter (D ) p Engine Determination of Engine Power (P) and Speed (n),. Stage 1 and Propeller Pitch for Maximum 0 Yes. Propeller. Stage 2. Given Dp[m], AE/Ao , z; v[m/s]; RT(v)[kN] Find. Does Modify Main Engine? No. Determination the Propeller Design Point. P[kW], n[1/s], Pi[m] Determination of the Propeller Principal Dimensions and Ship Speed for Maximum 0 (Optimization Problem). Given z; P[kW], n[1/s]; RT(v)[kN] Find. Dp[m], Pi[m], AE/Ao; v[m/s]. Determination of the Optimum Propeller Principal Dimensions and Ship Speed. Stage 3 Determination of the Ship Speed, Engine Power, EngineEngine Speed by Using the Given Propeller PropellerShip Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Determination of the Ship Speed, Engine Power, Engine Speed (Nonlinear Equation). Given Dp[m], Pi[m], AE/Ao, z; v[m/s]; RT(v)[kN] Find. P[kW], n[1/s] 43. [Stage 0] Assumption of the Propeller Diameter Propeller curve of the basis ship is drawn by connecting point (PMCR, nMCR) and origin (P=0, n=0). L1: NMCR(Nominal Maximum Continuous Rating). Propeller curve of the basis ship.  1st Method: Use the diameter of the basis ship.  2nd Method: When the diameter of the basis ship is not given, estimate the diameter as follows.. PMCR. Formula for estimation of propeller diameter (. ). 0.2. P  Dp  15.4   MCR3   c1  nMCR basis ship where,. 1 for 5 blades, 1.05 for 4 blades.. The MCR ( ) and rpm ( ship are used.. Delivered Power of the Main Engine:. PD.E .  n. ) of the basis. nMCR.  Power Absorbed by the Propeller:. Pprop.  n 3. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 44. 22. (23) 2019-07-22. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (1/10). Given. DP [m]: Propeller diameter (from basis ship) AE/AO: Expanded area ratio z: Number of blades Vs [m/s]: Ship speed. Engine. RT(V) [kN]: Resistance varied with ship speed Find. Pi [m]: Propeller pitch P [kW]: Delivered power to propeller from main engine (P=DHPR) n [1/s]: Engine speed. ※ ηR should be considered to change the delivered power from after body into the delivered power without hull because the POW curve was generated from propeller in open water. 45. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (2/10). Given Find. DP [m], AE/AO, z ; Vs [m/s]; RT(V) [kN] Pi [m] ; P [kW], n [1/s].  Condition 1: The propeller absorbs the torque delivered by main engine.. P    n 2  DP 5  KQ ⋯ (1) 2 n. Torque delivered by the main engine. =. Torque absorbed by the propeller. R . Q0 Q. where, P  DHP  R * R: The ratio between a propeller's efficiency attached to a ship (O,B) and in open water (O), that is, R = O,B /O = QO/QO,B Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 46. 23. (24) 2019-07-22. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (3/10). Given Find. DP [m], AE/AO, z ; Vs [m/s]; RT(V) [kN] Pi [m] ; P [kW], n [1/s].  Condition 2: The propeller should produce the required thrust at a given ship speed.. RT    n 2  DP 4  KT ⋯ (2) 1 t. The thrust which is required to propel the ship for the given speed. =. The thrust which is produced by the propeller. 47. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (4/10) By Using Optimization Method Given. DP [m], AE/AO, z ; Vs [m/s]; RT(V) [kN] 3 Unknowns. Find. Pi [m] ; P [kW], n [1/s].  Condition 1: The propeller absorbs the torque delivered by main engine.. where, P  DHP  R. 2 Equations. Nonlinear optimization problem.  Condition 2: The propeller should produce the required thrust at a given ship speed.. Objective Function: Maximum. o . T  VA J KT   DHP 2 K Q. Solve the nonlinear optimization problem. Then the main engine power (P) and the speed of main engine (n) of the design ship are determined. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 48. 24. (25) 2019-07-22. [Appendix] Optimization by Using Lagrange Multiplier Method (1/2) P 2 n.    n 2  DP 5  K Q. G1 ( Pi , n, P ) . P 2 n.    n 2  DP 5  K Q = 0  (a). RT    n 2  DP 4  KT 1 t G2 ( Pi , n) . RT    n 2  DP 4  KT  0  (b) 1 t. F ( Pi , n)  0 . J KT  2 KQ.  (c). 49. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Appendix] Optimization by Using Lagrange MultiplierJ K F ( P , n)     2 K Method (2/2) G1 ( Pi , n, P ) . P    n 2  DP 5  KQ (a) 2 n. G2 ( Pi , n) . RT    n2  DP 4  KT (b) 1 t. i. T. (c). 0. Q.  Lagrange function:. H ( Pi , n, P )  F ( Pi , n)  1  G1 ( Pi , n, P )  2  G2 ( Pi , n)  (d).  Stationary point of H: H Pi H n. H  Pi , n, P, 1 , 2   0. K K {( T )  KQ  ( Q )  KT } K Q Pi Pi J K    1  (   n 2  DP5  )  2  (   n 2  DP4  T )  (e) 2 KQ 2 Pi Pi K Q KT {( )  KQ  ( )  KT } K 1 J KT J P n      n  1  (    2  n  DP5  K Q    n 2  DP5  Q ) 2 2 2 n K Q 2 KQ 2   n n  2  (   2  n  DP4  KT    n 2  DP5 . KT )  0  (f) n. H 1  1   0  (g) 2   n P H P     n 2  DP 5  KQ  0  (h) 1 2 n R H  T    n 2  DP 4  KT  0  (i) 2 1  t Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 5 Equations: (e), (f), (g), (h), (i) 5 Unknowns: Pi , n, P , 1 , 2 This can be solved by using numerical method, for example, Newton-Raphson Method. 50. 25. (26) 2019-07-22. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (5/10) Calculation By Hand Given. DP [m], AE/AO, z ; Vs [m/s]; RT(V) [kN] 3 Unknowns. Find. Pi [m] ; P [kW], n [1/s].  Condition 1: The propeller absorbs the 2 Equality constraints. torque delivered by main engine.. P    n 2  DP 5  K Q ⋯ (1) 2 n. where, P  DHP  R. Nonlinear indeterminate problem.  Condition 2: The propeller should produce the required thrust at a given ship speed.. Objective Function: Find Maximum. .. J KT  o  2 K Q. RT    n 2  DP 4  KT ⋯ (2) 1 t. First assume the initial value of the propeller pitch and then determine the main engine power (P) and the speed of main engine (n) by iteration to satisfy the conditions (1) and (2). 51. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (6/10) Calculation By Hand 1. Given Find. 2. DP [m], AE/AO, z ; Vs [m/s]; RT(V) [kN] Pi [m] ; P [kW], n [1/s]. Express the Condition 2 as KT  c2 J . 2. Condition 2:. RT    n 2  DP 4  KT , 1 t. Advance Ratio:. J. VA VA n n  DP J  DP.  J  DP  RT 1 RT  2   4 4  (1  t )  DP n (1  t )  DP  VA  RT KT  J2 (1  t )  DP 2VA 2 RT , c2  KT  c2 J 2 (1  t )  DP 2VA 2. 2. KT . Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 52. 26. (27) 2019-07-22. [Stage 1] Determination of the Main Engine Power (P) Calculation By Hand and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (7/10) By using the POW-Curve (KT -KQ-J) of the series propeller data, for example, B-series propeller data,. 3. of the design propeller and the KT -KQ-J. calculate the intersection point (J1, KT1) between the. curve of the B-series propeller at a given pitch/diameter ratio (Pi/Dp)1. And read the KQ1 and η01 at J1.. Repeat this procedure by varying pitch/diameter ratio. KT ,O. KT. KT  c2 J 2 KT -KQ-J curve of the B-series propeller. of the design propeller. O. 0,1. Pi /DP. J. η0. KT. KQ. (Pi /DP)1. J1. η01. KT1. KQ1. (Pi /DP)2. J2. η02. KT2. KQ2. (Pi /DP)3. J3. η03. KT3. KQ3. KT  c2 J 2. , , ,. KQ1. KT3. at (Pi/Dp)3. KQ1. KT1. KT1. at (Pi/Dp)1. J1. KT2. J1. J. at (Pi/Dp)2. at (Pi/Dp)1. J3. J2. J 53. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 1] Determination of the Main Engine Power (P) Calculation By Hand and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (8/10) 4. By using the set of KT, KQ, η0 (varied with pitch ratio), determine Jx to maximize η0 and pitch/diameter ratio (Pi/Dp)x at Jx .. KT. Intermediate values are determined by interpolation.. ,. Pi /DP. J. η0. KT. KQ. (Pi /DP)1. J1. η01. KT1. KQ1. (Pi /DP)x. Jx. η0x. KTx. KQx. (Pi /DP)2. J2. η02. KT2. KQ2. (Pi /DP)3. J3. η03. KT3. KQ3. , , ,. KT  c2 J 2. KQ.x at (Pi/Dp)x KT3 at (Pi/Dp)3 KT.x KT1. at (Pi/Dp)x. KT2 at (Pi/Dp)2. at (Pi/Dp)1. J1. JX. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. J2. J3. J 54. 27. (28) 2019-07-22. [Stage 1] Determination of the Main Engine Power (P) Calculation By Hand and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (9/10). 5. By using Jx from Step 4, calculate nx.. Jx . 6. VA nx  DP. nx . VA DP  J x. By using K Q , x from the Condition 1 and Step 4, calculate Px.. Px 2 5    n x  DP  K Q , x 2n. Px  2    nx 3  DP 5  K Q. x. 55. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 1] Determination of the Main Engine Power (P) and Engine Speed (n), and Propeller Pitch (Pi ) for Maximum 0 (10/10) Propeller curve for the design ship is drawn by connecting DHP and origin (P=0, n=0).. Px (= DHPR) is determined from optimization. Propeller curve for the design ship. BHP . DHP  T : Transmission. T. efficiency. NCR  BHP(1  S .M / 100). PDHP. NCR BHP. MCR. Engine margin Sea margin. MCR  NCR / E.M E.M: Engine Margin. DHP. nNCR  3. NCR c3. nMCR  3. MCR c3. nMCR nx. nNCR. O (0, logc3). By using P and n required by the propeller, determine the NCR. , ( P  c3  n3 ). If the NCR and MCR are not in the. and MCR of the design ship. Check whether the NCR and MCR layout diagram of main engine, select ※ η should be considered to change the delivered power from after body into the delivered another engine. are Rin the layout diagram of main engine. power without hull because the POW curve was generated from propeller in open water. 56. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 28. (29) 2019-07-22. [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (1/8). Given. z: Number of blades Propeller Design Point P [kW]: Delivered power to propeller from main engine (NCR) n [1/s]: RPS at MCR. RT(V) [kN]: Resistance varied with ship speed Find. Engine. DP [m]: Propeller diameter Propeller. Pi [m]: Propeller pitch AE/AO: Expanded area ratio V [m/s]: Ship speed. 57. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Propeller Design Point - Matching the Propeller and Main Engine Requirements of Design ship Determination of Principal Dimensions and Cb, Lcb, Cm, Vs(Fn) Estimation of Resistance and Propulsion Power based on Empirical Methods, for example, Holtrop & Mennen (Cw, k, w, t, R) Prediction of Resistance and Propulsion Power by Applying Correction Factor Assume the Main Engine Power and Speed (RPS) Stage 0 Assume the Propeller Diameter (D ) p. Engine. Determination of Engine Power (P) and Speed (n), Stage 1 and Propeller Pitch for Maximum 0 Yes. Does Modify Main Engine? No. Determination the Propeller Design Point. Propeller. Stage 2 EnginePropellerStage 3 Ship. Determination of the Optimum Propeller Principal Dimensions and Ship Speed Determination of the Ship Speed, Engine Power, Engine Speed by Using the Given Propeller. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 58. 29. (30) 2019-07-22. Matching the Propeller and Main Engine in the Load Diagram in Logarithmic Scales M : Specified MCR for propulsion (DMCR or MCR) S : Normal continuous rating for propulsion (NCR). Continuous operation range of main engine Power, % of L1 110% Propeller Design Point (G1). 3.3% M. L1. 100% 90% 80%. PMCR. Curve 1: Propulsion curve, clean hull (light running) Curve 2: Propulsion curve, fouled hull and heavy weather (heavy running) Curve 4: Torque/speed limit at which an ample air supply is available for combustion and imposes a limitation on the maximum combination of torque and speed (proportional to n2) Curve 5: Maximum mean effective pressure level, which can be accepted for continuous operation Curve 6: Maximum power for continuous operation Curve 7: Maximum speed which can be accepted for continuous operation. 5% M derated 5% L1. NMCR MCR: Derated MCR Slope 1. mep. L3. 5M 6. 100%. PNCR. 70%. Engine margin: NCR = 90% of MCR. 95%. 85%. 75%. 7. 70%. Heavy running. 64%. 40% 70%. Sea margin. L2. G2 is the intersection point of the curve ① with the reduced power considering the sea margin and also propeller design point.. G2. 80%. 50%. G1. 4. 90%. 60%. S. Slope 2. L4. Light running. 2 1. 75%. 80%. 85%. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 90%. 95%. nNCR nMCR. 100% 105%. 59. Engine speed, % of L1. Matching the Propeller and Main Engine in the Load Diagram Propeller curve of increased resistance. Continuous operation range of a main engine. MCR point can be any point within the layout diagram. When choosing the MCR, we have to consider the revolution of propeller, fuel consumption, and propeller operation layout and others all together. Once the MCR point has been chosen, and provided that the shaft line and auxiliary equipment are dimensioned accordingly, the specified MCR point is now the maximum rating. That is, the standard of all power and number of revolutions becomes MCR.. Propulsion curve (fouled hull and heavy weather). ⑤. PMCR: 100%. Curve 1: Propulsion curve, clean hull (light running) Curve 2: Propulsion curve, fouled hull and heavy weather (heavy running) Curve 4: Torque/speed limit at which an ample air supply is available for combustion and imposes a limitation on the maximum combination of torque and speed (proportional to n2) Curve 5: Maximum mean effective pressure level, which can be accepted for continuous operation Curve 6: Maximum power for continuous operation Curve 7: Maximum speed which can be accepted for continuous operation. ⑥. M. I. PNCR. Engine margin: NCR = 90% of MCR. 100% mep PNCR: 90%. ④. S'. G1. S. Power (%). Torque Limit. G2. ③. ②. Propeller Design Point (G1). 3.3% M. ①. 90 Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. rpm(%). PD. E  PNCR n  nMCR. 5% M. P. Propulsion curve (clean hull) ⋅. G1 or G2 : Propeller Design Point. Sea margin. ⑦. 90% mep. RT Vs. O ,max  H R.  2    n 3  DP  KQ  c3  n 3 5. 96.7 100 nMCR. 105 108 M: Maximum continuous rating (DMCR or MCR) 60 S: Normal continuous rating (NCR). 30. (31) 2019-07-22. Propeller Design Point Propeller Design Point (G1). Power, % of L1. Continuous operation range of a main engine. PD. E  PNCR n  nMCR. 110%. 3.3% M. 5% M. L1. 100%. Propeller curve of increased resistance. 90%. 80%. L3. MCR NCR. 5% L1. 5. P. 6. M. Engine margin S = 90% of M. S. 70%. 4. S’. G1. 7 Heavy running. 50%. Light running. L4. 3. 2 1. 40% 70%. 75%. 80%. 85%. 90%. 95%. nNCR nMCR. J. VA n  DP. 100%. 105%. 110%. Engine speed, % of L1. VA  n  DP  J. If J is constant, engine speed is proportional to ship speed. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh.  2    n3  DP  K Q  c3  n 3 5. The reason why the propeller design point should be G1.. Sea margin L2 of G2. G2. 60%. RT  Vs.  O ,max  H  R. - If the propeller is designed at the point S, the propeller curve is the curve ②. When the resistance of ship increases with time, then the propeller curve will move to the curve ③. Thus the propeller and engine match at the point S’ which is not NCR. This means the engine power of NCR cannot be delivered to the propeller, which results in reduction of ship speed. - If the propeller is designed at the point G1, the propeller curve is the curve ①. When the resistance of ship becomes larger with time, the propeller curve ① will move to the curve ② so that the propeller operates at the point S (NCR). 61. [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (2/8) - Given: Engine Power, Engine Speed. Given Find. z ; PNCR [kW], nMCR [1/s] ; RT(V) [kN].  * draft h h. Dp [m] , Pi [m], AE/AO ; V [m/s].  Condition 3: Required minimum expanded blade area ratio for non-cavitating criterion can be calculated by using one of the two formulas. K: Single Screw = 0.2, Double Screw = 0.1. ① Formula given by Keller. AE / AO  K . 1.3  0.3z  T. . DP  p0  gh*  pv 2. or ② Formula given by Burrill. P0-Pv = 99.047 [kN/m2] at 15℃ Sea water. . h*: Shaft Immersion Depth [m] h: Shaft Center Height (height from the baseline) [m] T: Propeller Thrust [kN]. AE / AO  F  (0 /(1 / J )2 ) /[{1  4.826(1 / J )2 }  (1.067  0.229  Pi / D p )] F.  R  BP2 VA1.25 287.4(10.18  h)0.625. BP  n  P 0.5 / VA2.5 Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. v A  v  (1  w )[ knots ]. P  DHP  R [ HP ] n[ rpm]. 62. 31. (32) 2019-07-22. [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (3/8) By Using Optimization Method Given. z ; PNCR [kW], nMCR [1/s] ; RT(V) [kN]. Find. Dp [m] , Pi [m], AE/AO ; V [m/s]. 4 Unknowns. 2 Equality constraints.  Condition 1: The propeller absorbs the. 1 Inequality constraint. torque delivered by main engine.. P 5    n 2  DP  K Q 2n. Nonlinear indeterminate problem. where, P  DHP  R  Condition 2: The propeller should produce the required thrust at a given ship’s speed.. Objective Function: Maximum. o . RT 4    n 2  DP  K T 1 t. Propeller diameter (Dp), pitch (Pi), expanded.  Condition 3: Required minimum expanded blade area ratio for non-cavitating criterion.. AE / AO  K . 1.3  0.3z  T. . DP  p0  gh*  pv 2. J KT  2 K Q. blade area ratio (AE/AO) , and ship speed are determined to maximize the objective function. . by iteration. 63. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Calculation By Hand [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (4/8) 1. Assume the Expanded Area Ratio ( AE / Ao ) .. AO : Swept or disc area (πDP2/4) AE : Expanded blade area. Assume that the expanded area ratio of the propeller of the design ship is the same as that of the basis ship. 2. Assume the ship speed V.. 3. Express the Condition 1 as K Q  c4 J 5 . Condition 1:. P 2 n. V J A n  DP.    n 2  DP 5  K Q ,. . nJ 1  VA DP. KQ  .  nJ  P 1 P  5    3 3 2 n  DP 2 n   VA  P  n2 5 5 J  c4 J , 2  VA5. 5.  P  n2   c4   2   VA5  . K Q  c4 J 5 Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 64. 32. (33) 2019-07-22. Calculation By Hand [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (5/8) By using the POW-Curve (KT -KQ-J) of the series propeller data, for example, B-series propeller data,. 4. calculate the intersection point (J1, KQ1) between the. of the design propeller and the KT -KQ-J. curve of the B-series propeller at a given pitch/diameter ratio (Pi/Dp)1. And read the KT1 and η01 at J1.. Repeat this procedure by varying pitch/diameter ratio. KQ ,O. KQ. KT -KQ-J curve of the B-series propeller. 0,1. Pi /DP. J. η0. KT. KQ. (Pi /DP)1. J1. η01. KT1. KQ1. (Pi /DP)2. J2. η02. KT2. KQ2. (Pi /DP)3. J3. η03. KT3. KQ3. KQ  c4 J 5. K Q  c4 J 5. , ,. O. ,. KQ1. KQ3. at (Pi/Dp)1. KT1 KT1. KQ1 at (Pi/Dp)1. J1. J. J1. KQ2. at (Pi/Dp)3. at (Pi/Dp)2. J3. J2. J 65. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Calculation By Hand [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (6/8) 5. By using the set of KT, KQ, η0 (varied with pitch ratio), determine Jx to maximize η0 and pitch/diameter ratio (Pi/Dp)x at Jx . KT KQ O. Intermediate values are determined by interpolation.. ,. Pi /DP. J. η0. KT. KQ. (Pi /DP)1. J1. η01. KT1. KQ1. (Pi /DP)x. Jx. η0x. KTx. KQx. (Pi /DP)2. J2. η02. KT2. KQ2. (Pi /DP)3. J3. η03. KT3. KQ3. , , ,. KQ1 at (Pi/Dp)1. KQ  c4 J 5 KQ3 at (Pi/Dp)3. KQ.x at (Pi/Dp)x KQ2 at (Pi/Dp)2 KT.x at (Pi/Dp)x J1. JX. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. J2. J3. J 66. 33. (34) 2019-07-22. Calculation By Hand [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (7/8) Go to 5. Calculate DP.x by using Jx at Step 5.. Assume another expanded. 1. area ratio ( AE / Ao ) .. Go to. J. 6. VA n  DP. DP . x . 2. VA n Jx. Assume another speed V.. No!!. Do the values of DPx and KT.x satisfy the Condition 2? Check the Condition 2:. RT    n 2  DP. x 4  KT . x 1 t No!!. Yes!! 7. Does the expanded area ratio ( AE / Ao ) satisfy the Condition 3?. Check the Condition 3:. AE / AO  K . Yes!!. 1.3  0.3z   T. DP   p0   gh*  pv  2. STOP 67. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Calculation By Hand [Stage 2] Determination of the Propeller Principal Dimensions for Maximum 0 (8/8): Summary 1. Assume the Expanded Area Ratio ( AE / Ao ) .. 2. Assume the speed V.. 3. Express the Condition 1 as K Q  C1 J 5.. Condition 1:. P 5    n 2  DP  K Q 2n 1st Loop. 2nd Loop. 4. By using the set of KT, KQ, η0 (varied with pitch ratio) determine Jx to maximize η0 and pitch ratio (Pi/Dp)x at Jx .. 3rd Loop. 5. Calculate DP.x by using Jx at step 4: J x . 6. Do DPx and KTx satisfy the Condition 2?. 7. Does the expanded area ratio. VA . n  DP. x Condition 2:. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. RT    n 2  DP. x 4  KT . x 1 t. ( AE / Ao ) satisfy the Condition 3? 68. 34. (35) 2019-07-22. Relations between Propeller and Main Engine  The relations between rpm, efficiency of the propeller, and size of the main engine.  If the rpm of a propeller decreases, the optimum diameter of the propeller becomes larger, and the efficiency of the propeller increases.  If the rpm of a propeller increases, the optimum diameter of the propeller becomes smaller, and the efficiency of the propeller decreases. T KT  4  However, if the rpm of the propeller increases,   n 2  DP we can select smaller main engine. Q KQ    n 2  DP 5 V  Factors considered for selecting main engine J A Assume that J is constant. n  DP  Efficiency of the propeller If n decreases, DP increases. Then, KQ becomes smaller than KT. J KT TVA o    Finally, O increases.  Weight of the engine 2 K Q 2 nQ  Arrangement of the engine room  Initial investment cost (for large and low-speed diesel engine: about 180 $/PS in 1998)  Operation cost 69. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Appendix] Selection of Alternative MCR by Using Constant Ship Speed Lines (1/2)  For a given ship with the same number of propeller blades, but different propeller diameter, the following relation between necessary power and propeller speed can be assumed. . n  P2  P1   2   n1 . where, P: Propulsion power (DHP) n: Propeller speed : Constant ship speed coefficient (0.25~0.30 for bulk carriers and tankers, 0.15~0.25 for reefers and container vessels). Cf. for the given propeller (the same number of propeller blades and the same propeller diameter). Pprop.  n3 Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 70. 35. (36) 2019-07-22. [Appendix] Selection of Alternative MCR by Using Constant Ship Speed Lines (2/2). Changed propeller curve (e.g. diameter change). MP1 MP2 If rpm (n) decreases, DP increases. Then, O increases. Finally, the required DHP decreases.. Original propeller curve. To select MCR, consider followings: - Smaller engine power and lower engine speed - Derated power: NMCR DMCR - Fuel oil consumption - Propeller operating range Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. For any combination of power and speed, each point on the constant ship speed line gives the same ship speed. : Constant ship speed coefficient 0.25~0.30 for bulk carriers and tankers 71 0.15~0.25 for reefers and container vessels. [Appendix] Selection of Alternative Engine Type by Using Constant Ship Speed Lines Ex) For the basic selection of an engine of 8,000 BHP, 100 rpm, alternative study of selection of different engines in the range of 100~150 rpm. I: 4S60MC engine curve and optimized propeller curve II: 5S50MC engine curve and optimized propeller curve III: 5L50MC curve andSpring optimized propeller curve Innovative Ship andengine Offshore Plant Design, 2019, Myung-Il Roh. 72. 36. (37) 2019-07-22. [Appendix] Optimum Operating Point of Main Engine Considering the Fuel Oil Consumption. 6 5. Curve 1: Propulsion curve, clean hull (light running) Curve 2: Propulsion curve, fouled hull and heavy weather (heavy running) Curve 4: Torque/speed limit at which an ample air supply is available for combustion and imposes a limitation on the maximum combination of torque and speed (proportional to n2) Curve 5: Maximum mean effective pressure level, which can be accepted for continuous operation Curve 6: Maximum power for continuous operation Curve 7: Maximum speed which can be accepted for continuous operation Curve 8: Extended speed, provided torsional vibration conditions permit. 4. Optimum operating point of main engine considering the fuel oil consumption (“O”) is the basis for the guarantee SFOC.. 1 2. 5. 6. 1. 4 2. 8 7. M: Specified MCR of engine (MCR) S: Continuous service rating of engine (NCR) O: Optimizing point of engine (O) A: Reference point of load diagram (in general, A = M). * SFOC (Specific Fuel Oil Consumption). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 73. [Appendix] Example of Selection of Optimum Point “O” Considering SFOC (1/2). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 74. 37. (38) 2019-07-22. [Appendix] Example of Selection of Optimum Point “O” Considering SFOC (2/2) SFOC will be reduced about 2% at O1 than L1.. L70MC Engine SFOC will be reduced about 4% at O2 than L1. Other Engine. O1: Optimized in M O2: Optimized at 85% of power in M When we use L70MC engine, O2 has smaller SFOC than O1. Thus, O2 can be selected as a new M. 75. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 3] Determination of Ship Speed, Engine Power, Engine Speed by Using the Determined Propeller (1/5) - The propeller principal dimensions have been determined.. Given. DP [m]: Propeller diameter Pi [m]: Propeller pitch z: Number of blades AE/AO: Expanded area ratio Vs [m/s]: Ship speed. Engine. RT(V) [kN]: Resistance varied with ship speed Find. P [kW]: Delivered power to propeller from. Propeller. main engine (P=DHPR) n [1/s]: Engine speed. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. EnginePropellerShip. 76. 38. (39) 2019-07-22. [Stage 3] Determination of Ship Speed, Engine Power, Engine Speed by Using the Determined Propeller (2/5). DP, Pi, z, AE/AO; Vs [m/s]; RT(V) [kN]. Given Find. 2 Unknowns. P [kW] , n [1/s].  Condition 1: The propeller absorbs the torque. 2 Equations. delivered by main engine.. P 2 n.    n 2  DP 5  KQ ⋯ (1) where, P  DHP  R.  Condition 2: The propeller should produce the required thrust for a given ship speed.. RT    n 2  DP 4  KT ⋯ (2) 1 t. Nonlinear determinate problem Not an optimization problem. 77. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. [Stage 3] Determination of Ship Speed, Engine Power, Calculation By Hand Engine Speed by Using the Determined Propeller (3/5) 1. Express the Condition 2 as K T  c2 J . 2. Condition 2:. RT    n 2  DP 4  KT , 1 t. Advance Ratio:. KT . RT 1 RT   (1  t )  DP 4 n2 (1  t )  DP 4. KT . RT J2 (1  t )  DP 2VA 2. J.  J  DP     VA . c2 . Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. VA VA n n  DP J  DP 2. RT (1  t )  DP 2VA 2 78. 39. (40) 2019-07-22. [Stage 3] Determination of Ship Speed, Engine Power, Calculation By Hand Engine Speed by Using the Determined Propeller (4/5) 2. Propeller Open Water Curve (KT -KQ-J) of the series propeller data, for example, B-series propeller data. Calculate P (DHPR) and n. For example, P /D = 0.67. i P KT, 10KQ, Propeller Open Water Curve (KT -KQ-J) O of the series propeller data. Condition 2. 0.5 0.463 0.4. P  DHP  R. 2.0. DHP  2    n3  DP 5  K Q /  R. 1.8. . KQ. 0.2. KT 0.1. J = 0.351  n  0.30. 0.35. 1.6 1.4. BHP . 1.0. [kts]. /J2 12.5 13.0 13.5 14.0 14.5. 0.50. J. . Condition 1. RT  Vs. O ,max  H  R. DHP T. T : Transmission efficiency. ③. VA K T J  DP. 0.40 0.45. EHP. D. 1.2. KQ. RT (1  t )  DP 2VA 2. c2 . KT / J2. 1.435 0.3. KT  c2 , J2. EHP in calm water [PS] 1686 1965 2240 2536 2898. ① ②. ④ ③ BHP in calm water. / [RPM]. 0.381 0.380 0.379 0.377 0.375. 0.224 0.223 0.221 0.219 0.216. 1.374 1.418 1.435 1.443 1.470. 0.355 0.352 0.351 0.348 0.345. 202 212 221 232 243. 0.470 0.465 0.463 0.460 0.457. 2867 3367 3844 4376 5020. Repeat this procedure by varying ship speed.. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 79. [Stage 3] Determination of Ship Speed, Engine Power, Calculation By Hand Engine Speed by Using the Determined Propeller (5/5) rpm. 2′. 240. 1′. nMCR. How to determine service speed of the ship at the given power (NCR) [Example 1] rpm at MCR. 230 220 210. ① Propeller Curve in Calm Water. 200. 2. BHP (PS) 5,000. 1. ② Propeller Curve with Sea Margin. MCR NCR (15% S.M). 4,000. BHP. NCR Power. 15% derating [kts]. 3,000 Service Speed 2,000 13.5kts 12.5 13.0 13.5 14.0 14.5 Vs(knots) Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 12.5 13.0 13.5 14.0 14.5. EHP in calm water [PS] 1686 1965 2240 2536 2898. BHP in calm water. / [RPM]. 0.381 0.380 0.379 0.377 0.375. 0.224 0.223 0.221 0.219 0.216. 1.374 1.418 1.435 1.443 1.470. 0.355 0.352 0.351 0.348 0.345. 202 212 221 232 243. 0.470 0.465 0.463 0.460 0.457. 2867 3367 3844 4376 5020 80. 40. (41) 2019-07-22. [Stage 3] Determination of Ship Speed, Engine Power, Calculation By Hand Engine Speed by Using the Determined Propeller (5/5) rpm. 2′ 1′. 240. nMCR. 230. How to determine service speed of the ship at the given power (NCR) [Example 2] rpm at MCR. 220 210. ① Propeller Curve in Calm Water. 200. 2. BHP (PS) 5,000. 1. ② Propeller Curve with Sea Margin. MCR NCR (15% S.M). 4,000. BHP. NCR Power. 15% derating [kts]. 3,000 Service Speed 2,000 13.3kts. 12.5 13.0 13.5 14.0 14.5. EHP in calm water [PS] 1686 1965 2240 2536 2898. BHP in calm water. / [RPM]. 0.381 0.380 0.379 0.377 0.375. 0.224 0.223 0.221 0.219 0.216. 1.374 1.418 1.435 1.443 1.470. 0.355 0.352 0.351 0.348 0.345. 12.5 13.0 13.5 14.0 14.5 Vs(knots) Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 202 212 221 232 243. 0.470 0.465 0.463 0.460 0.457. 2867 3367 3844 4376 5020 81. 7.4 Example of Determination of Propeller Principal Dimensions and Main Engine Selection (for Step 2). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 82. 41. (42) 2019-07-22. Example of Determination of Propeller Principal Dimensions (1/9) Example) Determination of Propeller Principal Dimensions of DWT 7,400 ton/400TEU Container Ship.  * draft h h. Given Data  Power and Speed of Diesel Engine.  Miscellaneous Data. - NCR = 85% MCR, at 208 rpm. - h (Shaft Center Height): 2.35 [m] - h* (Shaft Immersion Depth): 4.15 [m]. - Propeller RPM : 220 rpm. - Draft: 6.5 [m]. - Blade Number (z): 4. - Sea Margin = 15%. - MCR = 4,500 PS, at 220 rpm.  Model Test Data 1 t 1 w. Ship Speed V [knots]. EHP in calm water [PS]. T [kN]. R [kN]. w. t. ηR. 12.5. 1686. 248. 192.5. 0.381. 0.224. 1.018. 1.254. 13.0. 1965. 278. 216.0. 0.380. 0.223. 1.022. 1.253. 13.5. 2240. 304. 236.8. 0.379. 0.221. 1.024. 1.254. 14.0. 2536. 331. 258.5. 0.377. 0.219. 1.026. 1.253. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. H . 83. Example of Determination of Propeller Principal Dimensions (2/9)  Propeller Design Point NCR = 3,825 [PS] NMCR = 220/60 [1/s]. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 84. 42. (43) 2019-07-22. Example of Determination of Propeller Principal Dimensions (3/9) 1. Assume the Expanded Area Ratio ( AE Assume. 2. / Ao ).. AE / Ao  0.55 .. Assume the ship speed V. Assume V.  13.5[kts].. V  13.5[ kts ]  13.5  0.5144  6.945[ m / s]. ※ If the ship speed changes, coefficients are determined by using linear interpolation.. Ship Speed V [knots]. EHP in calm water [PS]. T [kN]. R [kN]. w. t. ηR. 13.5. 2,240. 304. 236.8. 0.379. 0.221. 1.024. P  DHP  R  . NCR  0.736 T  R 1  Sea Margin /100. 3,825  0.736  0.98 1.024  2, 457 [kW] 1  0.15. H . 1 t 1 w. 1.254. * 1 [PS] = 0.73575  0.736 [kW] * T = 0.98 (engine at stern). ※ ηR should be considered to change the delivered power from after body into the delivered power without hull because the POW Curve was generated from propeller in open water. * 1 [PS] = 75 [kgfm/s] = 7510-3 [Mg]9.81 [m/s2][m/s] = 0.73575  0.736 [kW]. 85. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Example of Determination of Propeller Principal Dimensions (4/9) 3. Express the Condition 1 as. KQ  c4 J 5 .. VA  V (1  w)  6.945  (1  0.379)  4.313. 2, 457   220 / 60  P  n2   3.4367 c4  2  VA5 2 1.025  4.3135 2. 4.  K Q  c4 J 5  3.4367 J 5. By using the set of KT, KQ, η0 (varied with pitch ratio), determine Jx to maximize η0 and. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. KT at Jx .. K Q  c4 J 5. 86. 43. (44) 2019-07-22. Example of Determination of Propeller Principal Dimensions (5/9) P  2, 457[ KW ], n  220, VA  4.313[ m / s ], AE / AO  0.55, z  4. Calculation of intersection points Determination of Js for the intersection points Determination of J, Pi/DP to maximize O. KQ  c4 J 5 Series Propeller Data for KQ. K Q   Cs ,t ,u ,v  J s  Pi / DP    AE / AO   z v t. u. Pi /DP. J. η0. KT. 0.50. 0.3105. 0.4542. 0.1049. 0.60. 0.3323. 0.4711. 0.1428. 0.70. 0.3535. 0.4684. 0.1818. 0.80. 0.3737. 0.4570. 0.2215. 0.90. 0.3927. 0.4418. 0.2610. 1.00. 0.4105. 0.4252. 0.2999. 1.10. 0.4271. 0.4086. 0.3378 87/87 87. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Example of Determination of Propeller Principal Dimensions (6/9) 5. By using Jx from Step 4, calculate nx.. J. 6. VA n  DP. DP . VA 4.313   3.5396[m] n  J  220 / 60   0.3323. Do the values of DPx and KT.x satisfy the Condition 2? The thrust which is required to propel the ship for the given speed (TS) =. RT 236.8   304 [kN ] 1  t 1  0.221. The thrust which is produced by the propeller (TP).    n 2  DP  K T  1.025  (220 / 60) 2  3.5396 4  0.1428  308.8956 [kN ] 4. If TS < TP , the ship can go faster.. Assume higher ship speed and repeat steps 3 to 6.. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 88. 44. (45) 2019-07-22. Example of Determination of Propeller Principal Dimensions (7/9). T. Determination of ship speed to satisfy TS = TP. TP(1) TS(3) TP(2). TS(1). V(1). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. TS(2) TP(3). V(2). V1. V(3). V. 89. Example of Determination of Propeller Principal Dimensions (8/9) Propeller Principal Dimensions for Expanded Blade Area Ratio (AE/AO) of 0.55 AE/AO TP = 308.9 [kN]. TS = 304 [kN]. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 0.55. V (knots). 13.57. w. 0.3788. VA (knots). 8.4289. J. 0.3339. ηO. 0.4727. DP (m). 3.5416. Pi/DP. 0.60. TP (kN). 308.1892. TS (kN). 307.6054. (TP - TS). Error = 0.5838. 90. 45. (46) 2019-07-22. Example of Determination of Propeller Principal Dimensions (9/9) 7. Does the expanded area ratio ( AE / Ao ) satisfy the Condition 3?. AE / AO  K . 1.3  0.3z   T. . DP  p0  gh*  pv 2.  0.2 . . (1.3  0.3  4)  308.1892  0.6363 3.5416 2  (99.047  1.025  9.81 4.15. Assume another expanded ratio and repeat steps 2 to 7.. 91. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Check for the Required Minimum Expanded Blade Area Ratio. O. 0.7. AE/AO. Pi/DP. (AE/AO)min. AE/AO. DP. Final Result of Propeller Principal Dimensions. Required minimum expanded blade area ratio for non-cavitating criterion. Pi/DP 0.55. 0.55. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. J*. 0.65 13.48. w. 0.3791. VA (knots). 8.3696. J. 0.3329. ηO. 0.4650. DP (m). 3.5278. DP. Pi/DP. 0.65. O. KT. 0.1411. KQ. 0.0161. TP (kN). 301.1685. TS (kN). 302.9741. (TP - TS). -1.8056. AE/AO (Keller). 0.6401. 0.4 0.4. AE/AO V (knots). 0.7. AE/AO. 92. 46. (47) 2019-07-22. Reference Slides. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 93. Interaction between a Hull and a Propeller  Propeller has to work behind the ship and in consequence one has an interaction upon the other.  How does the hull affect the water in which the propeller is working? How does the propeller affect the hull?  A ship affects the water near its stern in 3 aspects:  Pressure increase at the stern  Boundary layer (a propeller is in the boundary layer or way of the ship.)  Water particle velocity induced by ship generated waves. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 94. 47. (48) 2019-07-22. The Influence of the Hull on the Propeller (1/2)  Wake factor (fraction)  Water particle velocity near the propeller is not the same as the ship velocity.. w  Vs  VA (Vs : Ship velocity, VA : Flow velocity at its stern) Froude wake factor: wF  Taylor wake factor: wT . Vs  VA Vs  VA  VA 1   wF . Vs  VA  VA  Vs (1  wT ) Vs. The relationship between Froude and Taylor wake factors: wT . wF 1  wF. or wF . wT 1  wT. When VA  Vs , positive wake (most cases, a single screw) When VA  Vs , nagative wake (only for high speed ship) Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 95. The Influence of the Hull on the Propeller (2/2)  Wake factor (fraction) (continued)  wT and wF are determined by the measurements made in a model test (near a hull’s stern) or in a real ship test.  Nominal wake: Wake measured near the stern of a hull in the absence of the propeller (using pilot tubes)  Effective wake: Wake measured in the presence of propeller. The measurements show that a propeller at a rotating speed n behind a hull advancing at velocity (Vs), delivers thrust (T). By comparing it to the results of the same propeller in the open water tests, we will find that at the same revolutions n, the propeller will develop the thrust T but at a different speed (usually lower), known as effective speed of advance (VA). The difference between Vs and VA is considered as the effective wake.  Relation between nominal wake and effective wake: Since propellers induce an inflow velocity which reduces the positive wake to some extent, the effective wake factor usually is 0.03~0.04 lower than the corresponding nominal wake.. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 96. 48. (49) 2019-07-22. The Influence of the Propeller on the Hull (1/2)  Thrust-deduction factor (fraction)  When a hull is towed, there is an area of high pressure over the stern, which has a resultant forward component to reduce the total resistance.  With a self-propelled hull (in the presence of the propeller), the pressure at the stern is decreased due to the propeller action.  Therefore, there is a resistance augment due to the presence of the propeller.  If T is the trust of the propeller and RT is the towing resistance of a hull at a given speed Vs, then in order that the propeller propel the hull at this speed, T must be greater than RT because of the resistant augment.  The normalized difference between T and RT, is called the thrustdeduction factor, and denoted by t.. t. T  RT R  1  T  RT  T (1  t ) T T. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 97. The Influence of the Propeller on the Hull (2/2)  Thrust-deduction factor (fraction) (continued). t. T  RT R  1  T  RT  T (1  t ) T T. where, RT : Total resistance of bare hull T : Thrust after subtracting the resistance of the rudder. and other stern appendages t : Measured in experiments depends, not only on the shape of the hull. and the characteristics of the propeller, but also the type of the rudder. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 98. 49. (50) 2019-07-22. Propeller Efficiency  The efficiency of a propeller in open water is called open water efficiency or propeller efficiency.. 0 . T  VA 2 nQ0. where, VA is the advance speed, T is the thrust, n is the rotation speed (number of rotations per unit time), and Q0 is the torque measured in the open water test when the propeller is delivering thrust T at the rotation speed n.  In the case the same propeller behind a hull, at the same advance speed it delivers the same thrust T at the same revolution n but needs torque Q. In general, Q is different from Q0. Then, the efficiency of the propeller behind the hull,. B . T  VA 2 nQ. 99. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. Relative Rotation Efficiency  The ratio of behind-hull efficiency to open-water efficiency is called the relative rotative efficiency.. R .  B Q0  , 0 Q. thus  B   R0.  The difference between Q0 and Q is due to  wake is not uniform over the disc area while in open water, the advance speed is uniform  model and prototype propellers have different turbulent flow. (Remember then Reynolds number are not the same). R. = 1.0~1.1 for single-screw ship = 0.95~1.0 for twin-screw ship. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 100. 50. (51) 2019-07-22. Hull Efficiency  The hull efficiency is defined as the ratio of the effective power for a hull with appendages to the thrust power developed by propellers.. H . EHP RT Vs 1  t   THP T VA 1  w. where, EHP : Effective horse power, EHP  RT Vs RT : Total resistance of bare hull Vs : Speed of the ship THP : Work done by the propeller in delivering a thrust T VA : Advanced speed. (= Speed of the propeller with respect to the ambient water). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 101. Propulsive Efficiency  The propulsive efficiency (Quasi-propulsion coefficient) is defined as the ratio of the effective horse power to the delivery horse power.. D . RV TVA RT Vs EHP  T s     B  H  O  R  H DHP 2 nQ 2 nQ TVA. where, EHP : Effective horse power, EHP  RT  Vs DHP : Delivered horse power, DHP  2 nQ. O : Propeller effiency in open water  R : Relative rotative efficiency  H : Hull efficiency. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 102. 51. (52) 2019-07-22. Cavitation on a Propeller (1/3)  Problems    . Decrease of the thrust of the propeller Decrease of its efficiency Cause of vibration of hull and the propeller Generation of uncomfortable noise Cause of erosion of the propeller blade.  Criteria for prevention of cavitation  Mean thrust loading coefficient. c . 1 2. T VR2 Ap. where,.  : Density of water, T : Thrust Ap : Project blade area,. Ap AD.  1.067  0.229. P D. VR : Relative velocity at 0.7 R of a propeller VR2  VA2   2  0.7 R  n . 2. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 103. Cavitation on a Propeller (2/3)  Cavitation Number  The cavitation is most likely to occur at the tips of blades where the relative velocity is the largest and the hydro-static pressure is the lowest when blades rotate to the highest position.  It can also occur near the roots where blades join the boss of a propeller because the attack angle is the largest.. . p0  pv 2 1 2 VR. where, p0 : Presuure at some point of a blade pv : Vapor presuure of water. Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 104. 52. (53) 2019-07-22. Cavitation on a Propeller (3/3). Innovative Ship and Offshore Plant Design, Spring 2019, Myung-Il Roh. 105. 53. (54)