Use of STAR-CCM+ for Heat Exchanger Product Development Gary Yu, - - PowerPoint PPT Presentation

▶
use of star ccm for heat exchanger product development
SMART_READER_LITE
LIVE PREVIEW

Use of STAR-CCM+ for Heat Exchanger Product Development Gary Yu, - - PowerPoint PPT Presentation

Mar 14, 2024 214 likes •425 views

DNMN Product Development Use of STAR-CCM+ for Heat Exchanger Product Development Gary Yu, Martin Timmins, Mario Ciaffarafa DENSO Marston Ltd. DENSO MARSTON LTD. DNMN Product Development DENSO Marston Founded in 1904 Acquired by DENSO in

slide-1
SLIDE 1

DENSO MARSTON LTD.

DNMN Product Development

Use of STAR-CCM+ for Heat Exchanger Product Development

Gary Yu, Martin Timmins, Mario Ciaffarafa

DENSO Marston Ltd.

slide-2
SLIDE 2

DENSO MARSTON LTD.

DNMN Product Development

  • Founded in 1904
  • Acquired by DENSO in 1989
  • Located in Shipley, West Yorkshire
  • Designs and Manufactures engine

cooling modules for Heavy Duty Cooling applications

  • Product Range includes radiators, oil

coolers, charge air coolers and condensers

DENSO Marston

slide-3
SLIDE 3

DENSO MARSTON LTD.

DNMN Product Development

1. Charge air cooler (CAC) is a typical fin-tube type cross flow heat exchanger; very fine mesh is required in CFD model to capture inner and external fin geometry features. 2. Further smaller mesh size is required to resolve thermal boundary layer. 3. Hundreds of millions of cells may be generated in CFD model for a conjugated heat transfer (CHT) study on a CAC of typical size in off-highway heavy duty vehicles. 4. Large computing resources will be required and therefore very inefficient.

Background

Core Depth Over Core Tube Inner Fin External Fin Charge Air Cooling Air

slide-4
SLIDE 4

DENSO MARSTON LTD.

DNMN Product Development

5. Can STAR-CCM+ single stream or dual stream heat exchanger model do the job? NO, it requires the input of test data and cannot be used for new product development. 6. An in-house program has therefore been developed and validated in DENSO Marston to build a virtual CAC prototype for prediction of heat rejection rate and pressure drop. 7. STAR-CCM+ has been used to find the key information of heat transfer and pressure drop in the new design.

Background

Core Depth Over Core Tube Inner Fin External Fin Charge Air Cooling Air

slide-5
SLIDE 5

DENSO MARSTON LTD.

DNMN Product Development

1. Use of STAR-CCM+ to study a very small section of inner and external fins to find heat transfer and pressure drop information. 2. Based on the information from Step 1, an in-house program using C++ is developed to build a virtual CAC prototype to predict the overall heat rejection rate, charge air core pressure drop and cooling air pressure drop. 3. Based on the charge air core pressure drop and overall heat rejection rate from Step 2, STAR-CCM+ single stream heat exchanger model is used to predict charge air pressure drop over tanks and core.

Methodology

1 2 3

slide-6
SLIDE 6

DENSO MARSTON LTD.

DNMN Product Development

Why STAR-CCM+ IS Required?

1 1 1

, , ,

h h h h

P T m 

 2 2 2

, , ,

h h h h

P T m 

 2 2 2

, , ,

c c c c

P T m 

 1 1 1

, , ,

c c c c

P T m 

(6) D L 2 1

c c 2

V f P

c c c c

    

) (Re , ) (Re

2 2 h h h c c c

F f F f   (7) D L 2 1

h h 2 

  

h h h h

V f P  (1) ) (

2 1 h h h h

T T m cp Q    

(3) T A U Q    

(4)

h h h

RT P  

h h c c

A A UA   1 1 1  

2 2

1 2 2 1 c c h h

T T T T T     

) (Re , ) (Re

1 1 h h h c c c

F Nu F Nu  

(2) ) (

1 2 c c c c

T T m cp Q    

(5)

c c c

RT P  

CFD is used for the solution

2 2 2 2 2 2 c c c h h h

P T P T Q   , , , , , ,

7 unknowns:

Additional unknowns introduced:

h c h c

f f Nu Nu , , ,

slide-7
SLIDE 7

DENSO MARSTON LTD.

DNMN Product Development

Determination of Computational Domain

Assumptions:

  • 1. Flow is uniformly distributed between each fin loop:
  • 2. Flow and heat transfer are same in each half external fin loop
  • 3. Flow is periodic between each inner fin loop

One loop of inner fin, 160 mm length, and half loop of external fin, 64 mm length, are modelled in CFD Periodic boundary condition Inner fin External fin

slide-8
SLIDE 8

DENSO MARSTON LTD.

DNMN Product Development

CFD Physics Model and Boundary Conditions

w

T

  • Mass flow inlet,
  • Temperature inlet,
  • Constant wall temperature,
  • Pressure outlet

m

in

T

m in

T

w

T

slide-9
SLIDE 9

DENSO MARSTON LTD.

DNMN Product Development

External fin Inner fin

Results – Y+ Value

1. Pressure drop between inlet and outlet and residuals monitored for convergence check 2. Fin wall Y+ value checked to make sure near wall viscous sub-layer resolved

slide-10
SLIDE 10

DENSO MARSTON LTD.

DNMN Product Development

Inner Fin Correlation: Nu v Re

viscosity dynamic fluid : area through flow : rate; flow mass : ty conductivi thermal fluid :  

C

A m

Inner Fin and External Fin Heat Transfer Correlations

diameter hydraulic : t coefficien fer heat trans averaged : Re ,

h h C h

D D A m D Nu    

 

External Fin Correlation: Nu v Re

slide-11
SLIDE 11

DENSO MARSTON LTD.

DNMN Product Development

h

D L V f P

2

2 1 

 

Inner Fin Correlation: Friction Factor v Re

Inner Fin and External Fin Pressure Drop Correlations

length fin : velocity; : density; : factor friction averaged : drop; pressure : L V f P 

h C

D A m

 Re

External Fin Correlation: Friction Factor v Re

viscosity dynamic fluid : area; through flow : diameter hydraulic : rate; flow mass : 

C h

A D m

slide-12
SLIDE 12

DENSO MARSTON LTD.

DNMN Product Development

  • 1. Discretise the heat exchanger core in hot flow direction by half of external fin

loop pitch and in cold flow direction by one inner fin loop pitch.

  • 2. Carry out heat balance and pressure drop calculation on each cell to get
  • verall heat rejection rate and core pressure drop on both flow sides.

Assumptions:

  • 1. Flow rate is uniform across each tube and each fin loop.
  • 2. Both fluids are ideal gas, no tube wall thermal resistance between hot and

cold fluids.

  • 3. No heat conduction along the tube in both flow directions.

Numerical Program for Calculation of Core Pressure Drop and Overall Heat Rejection Rate

slide-13
SLIDE 13

DENSO MARSTON LTD.

DNMN Product Development

Numerical Program Output – an Example Core Pressure Drop and Overall Heat Rejection Rate

slide-14
SLIDE 14

DENSO MARSTON LTD.

DNMN Product Development

Charge Air Total Pressure Drop (Tanks + Core)

Q

Outlet Tank Inlet Tank

In house program

STAR-CCM+ single stream heat exchanger model Q P over core

slide-15
SLIDE 15

DENSO MARSTON LTD.

DNMN Product Development

Validation Against CAC A Test Data, Face Area 0.525 m2

  • Heat Rejection Rate and Cooling Air Pressure Drop

Cooling Air Velocity m/s 4 6 8 10 Cooling Air Temp on

  • C

16.1 15.7 15.6 15.5 Charge Air Mass Flow kg/m 34.8 34.3 34.5 34.6 Charge Air Pressure In bar 1.9 1.9 1.9 1.9 Charge Air Temp In

  • C

184.4 184.0 183.4 183.0 Cooling Air P (Test) 100% 100% 100% 100% Cooling Air P (Prediction) 97.6% 96.5% 98.9% 102.1% Heat Rejection Rate (Test) 100% 100% 100% 100% Heat Rejection Rate (Prediction) 101.3% 100.3% 100.1% 100.1%

slide-16
SLIDE 16

DENSO MARSTON LTD.

DNMN Product Development

Validation Against CAC A Test Data, Face Area 0.525 m2

  • Charge Air Pressure Drop

Cooling Air Velocity m/s 2 2 2 2 Cooling Air Temp on

  • C

16.7 16.8 16.8 16.7 Charge Air Mass Flow kg/m 42.3 36.8 34.6 30.3 Charge Air Temp In

  • C

185.7 187.0 187.5 185.7 Charge Air Pressure In bar 1.9 1.9 1.9 1.9 Charge Air P (Test) 100% 100% 100% 100% Charge Air P (Prediction) 93.7% 99.3% 100.9% 106.9%

slide-17
SLIDE 17

DENSO MARSTON LTD.

DNMN Product Development

Validation Against CAC B Test Data, Face Area 0.074 m2

  • Heat Rejection Rate

Cooling Air Velocity m/s 8 8 8 8 Charge Mass Flow kg/s 0.35 0.30 0.25 0.20 Charge Mean Temp In

  • C

182.2 182.3 181.3 178.8 Heat Rejection Rate (Test) 100% 100% 100% 100% Heat Rejection Rate (Prediction) 98.1% 99.7% 99.2% 99.9% Cooling Air velocity m/s 4 6 8 10 Charge Mass Flow kg/s 0.26 0.26 0.25 0.25 Charge Temp In

  • C

181.9 181.5 181.3 181.0 Heat Rejection Rate (Test) 100% 100% 100% 100% Heat Rejection Rate (Prediction) 98.4% 99.3% 99.2% 100.8%

slide-18
SLIDE 18

DENSO MARSTON LTD.

DNMN Product Development

Summary

  • An in house program has been developed to predict the charge

air cooler (CAC) thermal performance based on heat transfer and pressure drop information obtained by two separate CFD detailed studies on CAC inner and external fins;

  • In the CFD detailed study, only a small section of external and

inner fin (one inner fin loop, half external fin loop) is modelled; the accuracy of this study is the key to the CAC thermal performance prediction;

  • STAR-CCM+ single stream heat exchanger model is used to

predict the charge air pressure drop over CAC tanks and core;

  • The developed methodology is validated against test results of

two CAC units;

slide-19
SLIDE 19

DENSO MARSTON LTD.

DNMN Product Development

THANK YOU