A Study on Inflow Rate Variation for Shrouded Wind Turbine Rotors

(1)

초 록

EDISON CFD .

. ,

.

goe 417 (5 , 10 ) ,

(Wind-lens)

, . .

Key Words : (CFD), (Shrouded rotor), (Wind-lens), (Circulation),

(Pressure down), (Mass flow rate), (Wind turbine), (Vortex)

. P=ρAV³/2 A V

.

. (Shroud)

.

,

. Aniket C. Aranake [1], Sheila Wi

dnall [2], C J Lawn [3] .

(Diffuser) (Brim)

.

Fig. 1 Airfoil circulation theory Fig. 2 Wind-lens theory

(2)

.

[4]

Wind-lens .

Shrouded rotor Wind-lens

EDISON CFD

. Wind-lens

(Diffuser) (Wind-lens)

. EDISON CFD

2 .

EDISON CFD

Wind-lens

.

goe 417 [5]

5 10

. 2

EDISON CFD “

2 SW (2D_I

ncomp_P)” . RANS

(Reynolds Averaged Navier-Stokes)

LU-SGS, Osher’s

upwind scheme . Menter’s k–ω

SST Viscous Adiabatic Wall,

Symmetry BC, Block Commun

ication, Far-Field BC .

Table 1 .

.

 



_^   (1)

__{ }

∞



(2)

 



_^^{⋅ }^^^{ }__^^_∞_ (3)

 (mass flow rate) , 

(non-dimensional mass flow

amplification factor),  (circulation) .

.

Fig. 5 .

_ . ^

. ^ 1 ^ _

1 . [5]

.

^∼ 

. [6] ^^^{∼ }

 × ^{ } Fig. 3 5kW Wind-lens turbines in a seashore

park in Fukuoka city, Japan

_∞(m/s) Reynolds

Number (Re) Density (kg/m³) CFL Time-marching Convergence

Criteria

12 800,000 1.225 1.0 LU-SGS 10^-4

Table 1 Flow condition

Fig. 4 Airfoil shrouded wind turbine

(3)

. 5

10 .

20 .

Wind-lens Fig. 8 .

Long type L/D=1.25 . W

ind-lens h/L=0.075

. [7] 2.3.1

^∼  . 4

10 Wind-le

ns 8 12

.

5 -6.3257 10 -9.0455

.

u, p streamline Fi

g. 13 . u

.

separation

Fig. 6 Grid system at    .

Fig. 7 Grid system at    Fig. 8 Wind-lens

Fig. 9 Grid system of Diffuser

Fig. 10 Grid system of Wind-lens

(4)

-3.2996

. 5

4

. goe 417

.

10% y

u Fig. 14 Fig. 15

.

sepa ration

. Table 2

Md Γ . Γ Md

.

. separation

(-) .

Wind-lens u, p, k streamline

Fig. 16 . u

. Wind-lens

separation Fig. 16 (a)

.

. Wind-lens inlet

. streamline

. Wind-lens (a) u (b) p (c) streamline

Fig. 11 Flow distribution around shroud at   

(a) u (b) p (c) streamline Fig. 13 Flow distribution around diffuser

(a) u (b) p (c) streamline Fig. 12 Flow distribution around shroud at   

(5)

0.0603 .

Wind-l ens

.

3.

, , Wind-lens

EDISON CFD . Fig. 14 y vs u at 0.1c of    and   

Shroud airfoil at ^{  } Shroud airfoil at ^{  } Diffuser

Md 1.2718 1.3730 1.1479

Γ -6.3257 -9.0455 -3.2996

Table 2 Comparison of amplication factor Md and circulation Γ

Fig. 15 y vs u at 0.1c of Diffuser

(a) u (b) p

(c) k (d) streamline

Fig. 16 Flow distribution around Wind-lens

Fig. 17 y vs u at 0.1c of Diffuser and Wind-lens

(6)

1. ^{  } Γ

=-6.3257, ^{  } Γ=-9.0455 7.76%

2.

3. .

.

4. 4 5

0.511

.

5. Wind-lens

2.51

3.54% .

separation .

0.0603 .

.

2015 ( )

(No. NRF-2011-0020557).

[1] Aniket C. Aranake, 2013, “Computational Analysis of Shrouded Wind Turbine Configurations”, 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, Vol.17, No.10, pp.1-4.

[2] Sheila Widnall, 2009, “Potential Flow Calculations of Axisymmetric Ducted Wind Turbines,”

[3] C J Lawn, 2002, “Optimization of the power output from ducted turbines,”

[4] Yuji OHYA, “The mechanism of acceleration of wind using a wind lens,”

[5] Aniket C. Aranake, 2013, “Computational Analysis of Shrouded Wind Turbine Configurations”, 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, Vol.17, No.10, pp.1-4.

[6] Salim M. SALIM, 2009, “Wall y+ approach for dealing with turbulent flow over a surface mounted cube: part 1-low reynolds number,” Seventh International Conference on CFD in the Minerals and Process Industries, Vol.7, No.2, pp.2-7 [7] S.A.H jafari, 2013, “Flow analysis of shrouded small wind

turbine with a simple frustum diffuser with computational fluid dynamics simulations,” Journal of Wind Engineering and Industrial Aerodynamics, Vol.102, No.15, pp.103-104