COOLING SYSTEM SIMULATION USING COMPUTATIONAL FLUID ... · Desenvolvimento do Produto B-TPG: Powertrain Concept Nome: Ricardo de Oliveira Silva 10.06.2013 Pág. 1 COOLING SYSTEM SIMULATION

Desenvolvimento do Produto B-TPG: Powertrain Concept

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COOLING SYSTEM SIMULATION USING COMPUTATIONAL FLUID DYNAMICS AND EXPERIMENTAL IMPUT DATA

Vehicular cooling system analysis: Gol - 1.6L TF.

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Agenda

CFD – Analysis Overview on Gol Analysis – Engine: EA111 - 1,6L; Cooling System Simulation (GT-Cool) Heat rejection measurements on EA111 1,6L; Vehicular measurements; GT-Cool Simulation of VW 230 GP – EA111 1,6L w/ E22.

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Methods of 3D simulation (CFD) and 1D simulation (GT-Cool)

The same input data from suppliers are used by both simulations.

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CFD Method

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CFD Method: Air flow and thermal characteristics (opportunities)

When the CFD supports a cooling analysis, the focus is the powertrain underhood simulation especially the air flow properties passing through the radiator.

Temperature

Pressure

Velocity

Tunnel, fuel tank, bumper, etc temperatures

Cooling of engine compartment components (wires, sensors, alternator, etc)

Points of underpressure in the engine compartment

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CFD Data to GT- Cool Analysis

Radiator

Radiator Temperature (ºC) Pressure (Pa) Ram Air pressure

Coefficient

Downstream 36 101366,3 0,97

Upstream 89 101272,1 -0,99

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GT-Cool data from CFD

before the radiator

after the radiator

The 36ºC is the air temperature downstream of the condenser (that is: before radiator).

This estimation considered the air mass flow through the condenser which is warmed by the heat rejected in the AC system.

This heat rejection was estimated though the condenser map from Denso and the refrigerant mass flow derived from experimental data of the AC system.

Ambient temperature: 26,85ºC (300K)

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GT-Cool Components Coolant - Distributor

Hoses Fan

Heat Transfer Module

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Heat Rejection Measurement

otoP

heat. specificcerature;inlet temp tperature;outlet temtrate; flow massm

rejection;heat Q

:Where

).(.

p

i

o

=====

−=

iop ttcmQ

In order to improve the accuracy of the simulation, the engine was instrumented and tested in different conditions (heat rejection/ pressure drop map).

pressure;inlet Ppressure;outlet P

drop pressure P:Where

i

o

===∆

−=∆ io PPP

Parts specially designed for the test

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Measurements on dyno bench w/ EA111 1,6L

Flow Rate device and engine speed measurement with grounding isolation system (designed by us)

Pressure, temperature and flow rate upstream of

the water pump

Assembling Engine Speed

- Pressure

- Temperature

- Flow rate

Inlet and outlet temperature and pressure Pressure after

the pump

Data aquisition

C-Daq

The instrumentation must be done specifically for each engine. The same instrumentation used on the dyno bench was transferred to the vehicle.

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Input data: Drop pressure curves – Heat Exchanger

y = 0,0553x2 - 0,0164x - 0,0083R2 = 0,9945

y = 0,0868x2 - 0,0317x + 0,0027R2 = 0,9995

y = 0,137x2 + 0,2668x - 0,1746R2 = 0,9963

y = 0,0257x2 + 0,0182x - 0,0185R2 = 1

0,000

0,200

0,400

0,600

0,800

1,000

1,200

1,400

0,500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000Mass Flow Rate (kg/s)

Dro

p P

ress

ure

(bar

)

100% openned 66% openned 33% opennedVehicular test: 3th gear 100km/h Free Throttle: 1000 to 6000 rpm Poly. (100% openned)Poly. (66% openned) Poly. (33% openned) Poly. (Free Throttle: 1000 to 6000 rpm)

100% 66%

33% 0%

Vehicle measurement

The press. drop in the vehicle is lower than any position of the valve in dyno. To increase representativeness, it’s necessary to reduce restriction on dyno heat exchanger.

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y = 0,0956x2 - 0,038x - 0,0289R2 = 0,9963

y = 0,1146x2 - 0,0116x - 0,0608R2 = 0,9993

y = 0,1257x2 + 0,3648x - 0,2783R2 = 0,9949

y = 0,0505x2 + 0,0338x - 0,1091R2 = 0,9999

0,000

0,200

0,400

0,600

0,800

1,000

1,200

1,400

0,500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000Mass Flow Rate (kg/s)

Dro

p P

ress

ure

(bar

)

100% openned 66% openned 33% opennedVehicle Test - 3th Gear 100 km/h Free Throttle: 1000 to 6000 rpm Poly. (100% openned)Poly. (66% openned) Poly. (33% openned) Poly. (Free Throttle: 1000 to 6000 rpm)

Input data: Drop pressure curves – Engine Block

100% 66%

33% 0%

The press. drop through the engine block is influenced by the dyno heat exchange pressure drop.

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Input data: Dyno Map of Heat Rejection to the Coolant

Kennfeld of Heat Rejection

y = 0,0533x + 9,3788R2 = 0,3719

y = 0,0862x + 15,625R2 = 0,8959

y = 0,1219x + 27,19R2 = 0,8364

y = 0,1599x + 42,615R2 = 0,9458

y = 0,2151x + 47,88R2 = 0,8572

y = 0,2071x + 68,755R2 = 0,9038

0,00

10,00

20,00

30,00

40,00

50,00

60,00

70,00

80,00

90,00

100,00

0 20 40 60 80 100 120 140 160

Torque (Nm)

Hea

t Rej

ectio

n (k

W)

1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm 6000 rpmLinear (1000 rpm) Linear (2000 rpm) Linear (3000 rpm) Linear (4000 rpm) Linear (5000 rpm) Linear (6000 rpm)

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Input data: % of throtle x torque Kenfeld of Torque

0

20

40

60

80

100

120

140

160

0 10 20 30 40 50 60 70 80 90 100

% of Throtle body's opening

Torq

ue (N

m)

1000 rpm1250 rpm1500 rpm1750 rpm2000 rpm2250 rpm2500 rpm2750 rpm3000 rpm3250 rpm3500 rpm3750 rpm4000 rpm4250 rpm4500 rpm4750 rpm5000 rpm5250 rpm5500 rpm5750 rpm6000 rpm

This map is necessary in order to the GT-Cool to determine the the engine load.

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Link between GT-Cool and GT-Drive

Dyno Data and GT-Drive Interaction

CFD Input Data

CFD Input Data

Subassemblies

3rd Gear – 100km/h

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Parameters of reference – 3rd Gear – 100km/h – E22

Engine Speed = 4922 rpm

Heat Rejected =52,45 kW

Average Engine Speed = 4657 rpm

Average Heat Rejected = 50,8 kW

The heat rejected was measured in the vehicle. The value is similar to that predicted by the GT-Cool for this condition.

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ETD for 3rd Gear - 100km/hr – E 22 - Comparison

Ambient temperature =26,85 ºC

Steady temperature= 102.60 ºC

ETD = 75,75 ºC

TMeasured= 101,27 ºC

Tambient= 26,44 ºC

ETD= 74,83 ºC

Error% = 1% Tmáx=103,17ºC

evaluated range

The predicted stabilization (outlet engine) temperature is close (1% difference) to the measured value in the vehicle.

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Conclusion

•The next step will expend time on the heat rejection simulation;

•Improve the 1D underhood simulation, in order to reduce CFD dependency;

•1D simulation is faster then CFD, but 1D depends of CFD data.

Documents

COOLING SYSTEM SIMULATION USING COMPUTATIONAL FLUID ... · Desenvolvimento do Produto B-TPG: Powertrain Concept Nome: Ricardo de Oliveira Silva 10.06.2013 Pág. 1 COOLING SYSTEM SIMULATION