PERFORMANCE IMPROVEMENT OF A RANGE HOOD SIROCCO FAN BY CFD FLOW ANALYSIS

한 병 윤,

^*1

¹

²

³

P ERFORMANCE I MPROVEMENT OF A R ANGE H OOD S IROCCO F AN BY CFD F LOW A NALYSIS B.Y. Han, ^*1 J.W. Park, ¹ M.S. Lee ² and H.K. Park ³

This study is to investigate the air flow around a sirocco fan which is used in a range hood. The main object of the study is to improve the flow rate of the fan by analysis of unsteady 3-dimensional incompressible flow.

Overall analysis is carried out using CFD method. For this, we used a commercial code, SC/Tetra, and used a sliding mesh method to give the same condition as an actual state.

First, verification of the CFD results is done by comparing the experimental data with the numerical data for the suction flow rate. It is confirmed that two results are well consistent. Then for the improvent of flow rate, the effect of shape factors such as diameter ratio of fan, geometry of case, cut-off aperture and guide angle of case exit on the suction flow rate was considered. Especially, for a new design of housing, the principle of Archimedes spiral was used. The overall analysis was applied to a new design of housing, and the result showed an increase of flow rate by 10.7%.

Key Words : (CFD), (Unsteady Flow), 3 (3-D Analysis), (Sirocco Fan),

(Range Hood)

* Corresponding author, E-mail: [email protected]

1.

. ,

.

. ,

. ,

(range hood) .

[1-2]

(sirocco fan) .

(backward curved centrifugal fan) ,

, [3-4].

. [5] STAR-CD

2

, [6]

. Morinushi[7], Raj and Swim[8], Maeng[9]

.

.

SC/Tetra

Fig. 1 Schematic of the sirocco fan

fan

outer diameter 

0.161m inner diameter 

0.140m

number of blades  50

blade width  0.065m

inlet blade angle 

115°

outlet blade angle 

170°

housing

inlet diameter  0.135m

outlet area 0.157m × 0.087m Table 1 Geometry of the Range Hood

Fig. 2 Schematic of the experiment apparatus

Fig. 2 Schematic of the experiment apparatus 3

.

2.

2.1

Fig. 1

Table 1 .

Fig. 2

, ,

. 4

156.6mm, 2600mm

. ( ~U )

.

2.2

1000 rpm (Mach Number)

0.3 .

Navier-Stokes

, .

  _

 _

  (1)

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 _

 ^{  } 

   

  ^{    }

  _ 

  ^{  }

⁽²⁾

(1) , (2) .

, 2-

. 2- Standard   

.

. Wilcox[10]    2- viscous sublayer

[11].

SST(Shear-StressTransport)    .

(a) Total grid system (b) Blades Fig. 3 Computational grids

  ^{     } 

 _ 

 ^{  } 

  ^{   } 

 _

 ^{ } 

  ^{        (3)}

  ^{      } 

  _   ^

  _

 

   ^{   } 

 _

 ^{ } 

 

  _{ }

 _

  _   ^

(4)

(3), (4) SST    .

, ,

.

2.3

CFD

. (MRF, multiple

reference frame method) (sliding mesh method) .

.

SIMPLEC .

2.4

.

. SC/Tetra Pre-Process

100

, 20

. Fig. 3(a)

, Fig. 3(b) .

, Free Stream U ,

0.99U δ .

Blasius solution .

  ^  

   (5)

, 20    ×  ^  ^ 

,

   , x

0.007m . ,

0.4mm ,

,   ∼  ^{ } 

. , 3

.

, 600~1000rpm

0.000333 , no-slip

.

Fig. 4 Pressure and flow rate

Fig. 5 Flow coefficient and head coefficient

Fig. 6 Comparison of flow rate and rotation speed between experiment and computation

(a) logarithmic spiral (b) Archimedean spiral Fig. 7 Logarithmic spiral and Archimedean spiral

degree(  ) radius(  ) degree(  ) radius(  )

60  87.88mm 240  113.01mm

90  92.07mm 270  117.20mm

120  96.25mm 300  121.39mm

150  100.44mm 330  125.58mm

180  104.63mm 360  129.76mm

210  108.82mm

Table 2 Specification of the Housing

3.

3.1

Fig. 4 -

- .

. Fig. 5

. (  ) (  )

[12].

    ^

 (6)

   ^{ } 

 _   _

   ^{×  (7)}

,  ,  , 

,  _ ,  _ .

Fig. 5

.

. Fig. 6

.

Fig. 8 Cut-off gap

(a) 0.19D

(b) 0.08D

Fig. 9 Blade passage flows

Fig. 10 Shape of housing

1.6%

7.8%, 14.8%

.

.

.

, .

3.2

.

. Fig. 7(a) (logarithmic

spiral) .

. 

(8) .

   _  ^ (8)

Fig. 7(b) (Archimedean spiral)

.

 

.  (9)

.

   _   (9)

 _ ,  ,  , 

.

[13]

,

.

 8 

 Table 2 .

3.3

 _   _ 0.8~0.9 .

[14]  _   _

0.9 0.9

 _ ^  _ 0.87 0.88 .

Fig. 11 Comparison of pressure between original type(up) and modified type(down)

(a) Guide vane(5 degree) type (b) Straight type Fig. 12 Comparison of outlet shape effect

3.4 (cut-off) (Fig. 8) .

,

.

Morinushi[15] (9) .

    _ (9)

  _   _ .

(9) .

Fig. 9  50 70

( ) . Fig.

9(a)   _ 50

,   _

70 .

  _ .

3.5 Fig. 10

R10.8mm R3.2mm

. Fig. 11

, 0.6%

.

Table 2 .

4.4% ,

10.7% .

 7

1.6%

8.3%

.

.

 8

Fig. 12(a)   

5 Fig. 12(b)

8%

. Figs. 13,14

Fig.13 Velocity vector of guide vane type(5 degree)

Fig.14 Pressure field of guide vane type(5 degree)

Fig.15 Velocity vector of straight type

Fig.16 Pressure field of straight type

, Figs. 15,16 .

4.

SC/Tetra . . 1)

.

.

2) ,

.

3)   _   _

2 ,

. 4)

8~10%

.

5)    5

8% .

6)

.

.

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,”

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,”

, , pp.131-136.

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,”

, pp.572-577.

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,” ‘97

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