Cooling System Simulation for Indian Utility Vehicle using COOL3D

Indian GT SUITE Conference 2013 Cooling System Simulation for Indian Utility Vehicle using COOL3D Paper presented by Rishabh Pandey, M&M Gopakishore Gummadi, M&M Copyright 2012 Mahindra & Mahindra Ltd. All rights reserved. 1

AGENDA COOL3D AIR SIDE MODELLING. Methodology of Underhood Modelling. Discretization of flow boundary and components. Vehicle level Boundary conditions. Results. COOL3D COOLANT TEMPERATURE PREDICTION. Engine coolant temperature prediction. Fan sensitivity Analysis. Transient coolant temperature Prediction. CONCLUSIONS & FUTURE STUDY. 3

COOL3D AIR SIDE MODELLING Importance of Under Hood Components Modeling - Exploded View Layout of Vehicle Under Hood Components. Under hood components defines the vehicle level under hood restrictions for air. Air entry, Air exit will be decided by Under hood components positioning. Better airflow and under hood thermal management possible by optimizing the relative positions of the under hood components. 4

COOL3D AIR SIDE MODELLING Methodology For Airflow Path Modeling - COOL3D Approximated model Extraction of Under hood Geometries Vehicle Level Engine Compartment Approximations made for analysis All the grills are assumed in same plane. Grille mesh not considered. Components above engine are not considered. Engine block and transmission simplified & approximated. Vehicle Grill Model Cool 3D Grill Model 5

COOL3D AIR SIDE MODELLING COOL3D Under Hood Model ( Full Representation)- Sealing Draft Air Entry Fan & Shroud Assy. Engine & Transmission Components Included Are Grille openings, Condenser, Radiator, Fan & Shroud, Engine, Transmission, Air baffles, Under apron cover. 6

COOL3D AIR SIDE MODELLING COOL3D Approximated model Discretization pattern GT SUITE MODEL FOR THE ABOVE DISCRETIZED MODEL 7

VEHICLE LEVEL BOUNDARY CONDITIONS Operating Condition Cond.1 Cond.2 Cond.3 Vehicle speed Idling 50KMPH 50KMPH Fan speed Full Full Full Fan config. (Watts) A A B ** Fan B is 70W greater than Fan A Inputs For the Analysis - Dp Flow rate Fan Performance Curve. Radiator Performance Curve. Condenser air side restriction. Condenser heat rejection. Engine heat rejection. Fan Curve 8

Condition 1 (idling) Study of velocity distribution Velocity Profile Condenser Outlet Surface Max Velocity Region correlates COOL 3D Normal Velocity Profile CFD Normal Velocity Profile The Actual Bottom Grille is in oblique plane. But, Cool 3D approximation is in vertical plane. Maximum Localized velocity prediction location is approximately correct and max velocit prediction with error percentage of 8.6 % 9

Condition - 1 Study of velocity distribution Velocity Profile Radiator Outlet Surface COOL 3D Normal Velocity Profile CFD Normal Velocity Profile COOL3D Predicts the Localized Maximum Velocity with 6.5% error compared to CFD. The effect of Grille assumption minimized on Radiator outlet surface. 10

Condition - 1 Study of Average Velocity GT- SUITE ANALYSIS - Condenser Radiator **The average velocity found out by dividing volumetric flow rate with CSA of heat exchanger The Radiator average velocity is matching upto 9% of error with CFD. The Condenser average velocity is matching upto 0.6% of error with CFD. 11

Study of velocity distribution Condition 2 (50KMPH) Velocity Distribution for Condenser Correlates in fan swept area COOL 3D Normal Velocity Profile CFD Normal Velocity Profile Maximum velocity prediction location is approximately correct and max velocity prediction with error percentage of 10 % Velocity Distribution for Radiator Velocity Trends are inline with CFD. COOL 3D Normal Velocity Profile CFD Normal Velocity Profile Maximum velocity prediction location is approximately correct and max velocity prediction with error percentage of 10 % 12

Condition - 2 Study of Average Velocity GT- SUITE ANALYSIS - Condenser Radiator **The average velocity found out by dividing volumetric flow rate with CSA of heat exchanger The Condenser average velocity is matching upto 9.3% of error with CFD. The Radiator average velocity is matching upto 1.75% of error with CFD. 13

COOL3D COOLANT TEMPERATURE PREDICTION Coolant circuit Air side will be further validated through study of its impact on Coolant side - Top tank temperature prediction in different testing conditions. Sensitivity analysis of the different fans on coolant temperature. Coolant Temperature study for the given duty cycle. 14

COOL3D COOLANT TEMP. PREDICTION Study Of Fan Influence on Coolant Temperature in GT Suite Condition 2 (Fan A) Condition 3 (Fan B) Engine Coolant Outlet Temperature Engine Coolant Outlet Temperature In Vehicle testing we analyzed that ROA value for FAN B was 2 Deg lesser than FAN A. In GT Analysis The Max coolant temperature stabilized at 2Deg C lesser for Fan B compared to Fan A. 15

Transient Temperature Prediction Temperature (Deg C) Studying logged data in the physical vehicle testing and RESULTS predicted by GT- Suite Starting from coolant temperature 69 deg Celsius in both the conditions. Steady state temperature behavior comparison is presented. Time (S) Hence simulation and test condition behavior is synchronized up to a good level. 16

OBSERVATIONS The air side velocity distribution & top tank temperature predictions performed and correlated with experiments with 90% accuracy. Optimizing the cooling system positions for new projects and making guidelines. Cool 3D can be used for temperature predictions & for air side velocity distribution with reasonable accuracy. The iterations on CFD will be reduced as it involves lot of computational effort. It can be used only for confirmation run. COOL3D will be initiated in the concept stage of the project. Doesn t require detailed modeling. 17

FUTURE STUDY The coolant flow distribution analysis for engine accessories Engine coolant temperature study for transient duty cycle. Fan duty cycle predictions. 18

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