Engineering Center Steyr GmbH & Co KG (ECS)mdx2.plm.automation.siemens.com/sites/default/files/...1,22 1,41 • Reduction of the driving velocity of the free driving vehicle • Adaption

Engineering Center Steyr GmbH & Co KG (ECS)

Analysis of the airstream in the ECS roller dynamometer building

Stefan Schnörch

© ECS / Disclosure or duplication without consent is prohibited

Overview

1) Company profile

2) Description of the roller dynamometer

3) Simulation approach

4) Preparation of the simulation models

5) Evaluation of the simulation results

6) Verification with measurement results

7) Determination of optimization potentials

Stefan Schnörch 2 21 March 2012


Company profile

3

ECS – Engineering Center Steyr

• Commercial Vehicle Engineering

• Powertrain Systems

• Electronics & Electric

• Low Volume Production

• Software & Simulation

• Testing Services

Magna

Seating

Seating

Systems

Cosma

International

Body & Chassis

Systems

Magna Exteriors and Interiors

Exterior

Systems

Interior

Systems

Vision

Systems

Closure

Systems

Magna Mirrors &

Magna Closures

Powertrain &

Engineering

Electronic

Systems

Magna Powertrain Magna Steyr

Engineering

& Assembly

Roof

Systems

E-Car Systems

(J.V.)

Hybrid &

Electric

Vehicles

MAGNA International

21 March 2012 Stefan Schnörch

© ECS / Disclosure or duplication without consent is prohibited Stefan Schnörch 4 21 March 2012

Usage of the roller dynamometer:

• Acoustic and vibration analysis

• Energy and thermal management

• Emission und consumption optimization

Vehicle cooling:

• Wind tunnel

Airflow: 140.000 m³/h

Variable outlet: 0,54 … 1,8 m²

• Temperature condition -10°C up to 50°C

Description of the roller dynamometer building


Description of the roller dynamometer building


Simulation of the airstream:

• Powerful fan

• Sound absorber

• Outlet nozzle

• Recirculation and conditioned

airstream channel

Task of the CFD simulation:

• Determination of the maximum representable airstream velocity

→ for the different nozzle types

Nozzle types:

V1 V2 V3 V4 The following results are based

on nozzle type 2!

Outlet

Inlet

outlet nozzle


Simulation approach

Adaption of the simulation model with measurements:

• Determination of the velocity in the outlet face of the nozzle


Arrangement of the measuring points:

CFD simulation:

• stationary

• isothermal

• Realizable k-ε model


Simulation approach

Results of the empty roller dynamometer building:

• Cut in a height of 0,3 m

7 Stefan Schnörch 21 March 2012

• Verification of the simulation results with additional measurements in the

building and results of the literature.

• Cut through the middle


Preparation of the CFD simulation models


Velocity Inlet

Pressure Outlet

Roller dynamometer including vehicle:

• Import of a vehicle into the roller dynamometer building

− Simplified vehicle model

• Modelling approach:

− Cooling package → porous medium

− Fan → momentum source term

− Tires and rolls → moving wall

Simulation model of the free driving vehicle:

• Virtual wind tunnel


Evaluation of the simulation results

Variant 1: Roller dynamometer

• Maximum fan power

• Average velocity of 182 km/h in

the outlet face of the nozzle

Variant 2: Free driving vehicle

• Chosen driving velocity: 182 km/h





Roller dynamometer

(182 km/h)

Free driving vehicle

(182 km/h)

• Velocity magnitude

• Radiator rear

Condenser

Radiator

Mass flow through the radiator [kg/s] Mass flow through the radiator [kg/s]

1,22 1,41

• Reduction of the driving velocity of the free driving vehicle

• Adaption of the driving velocity with KULI® (1D Thermal Management Software)



Task of KULI®:

• Determination of the driving velocity

→ Advantage: Reduction of the calculation time (1D simulation)

Approach:

1) Set up of the KULI® model

2) Adaption of the KULI® model to the

CFD simulation

3) Determination of the driving velocity


KULI® air path:

Resistance of the engine compartment

(Built in resistance)




Adaption of the KULI® model to the CFD simulation (free driving vehicle)

• Definition of the air mass flow through the radiator (Optimization target)

• Built in resistance (Optimization parameter)




KULI® model for the determination of the driving velocity

• Definition of the air mass flow through the radiator (Optimization target)

• Driving velocity (Optimization parameter)






• Adapted velocity: 156 km/h


Mass flow through the radiator [kg/s] Mass flow through the radiator [kg/s]

1,22 1,23








Underbody mass flow [kg/s] Underbody mass flow [kg/s]

11,07 14,58

Evaluation face

© ECS / Disclosure or duplication without consent is prohibited Stefan Schnörch 16 21 March 2012

Mercedes, C-class Maximum representable driving velocity [km/h]:

Outlet nozzle: Underhood flow Underhood flow

+ Underbody flow

V1

V2 156 -

V3

V4 not suitable not suitable

V1 V2 V3 V4


Mercedes, C-class Maximum representable driving velocity [km/h]:

Outlet nozzle: Underhood flow Underhood flow

+ Underbody flow

V1 → 90

V2 156 -

V3 → 125

V4 not suitable not suitable


Verification of the simulation results


Measurements in the roller dynamometer building:

• Vehicle: Mercedes, C-class

Measuring devices:

• Prandtl tube

• Pressure measuring device




Arrangement of the measuring points:

Measuring point 1:

- Lower grill

Measuring point 2:

- Underbody



Comparison of the measurement and simulation results:


Measurement (V2):

Simulation:

• Comparison shows a good correlation in the underbody measuring point

• Deviations are based on the simplified vehicle model


Determination of optimization potentials

Variants:

1) Optimization of the outlet nozzle

2) Optimization of the flow through the underbody

3) Adaption of the airstream in the roller dynamometer building



Adaption of the airstream through an additional outlet nozzle

• Focus of the airstream to the vehicle









Outlet nozzle: Variant 1 Variant 2

Mass flow through the radiator [kg/s] 1,24 1,24

Underhood mass flow [kg/s] 14,93 14,62



Thank you for your attention!


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Engineering Center Steyr GmbH & Co KG (ECS)mdx2.plm.automation.siemens.com/sites/default/files/...1,22 1,41 • Reduction of the driving velocity of the free driving vehicle • Adaption