A CFD-Based Numerical Evaluation, Assessment and Optimization of Conjugate Heat Transfer for Aerodynamic Cooling of a Wheel-Hub-Motors in Micro-Mobility Vehicles

Arun Mambazhasseri Divakaran, Evangelos Gkanas, Simon Shepherd, James Jewkes, Essam Abo-Serie

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Micro-mobility vehicles such as electric scooters and electric bikes for urban transportation are gaining attention globally. Addressing thermal issues in such vehicles could enhance the performance, reliability and range. This paper investigates the steady state conjugate heat transfer thermal analysis of wheel-hub-motor (500W) commonly used in micro-mobility vehicles using the computational fluid dynamics (CFD). A commercially available CFD platform, StarCCM+ is used for the conjugate heat transfer analysis of the wheel-hub-motor. The CAD model of wheel-hub-motor used for simulation modelling and analysis resembles an external rotor permanent magnet (PMs) brushless DC topology. Both internal and external fluid flow dynamics are considered simultaneously to determine the thermal path and associated thermal resistance which guided in further pertinent modifications on geometry to enhance the heat transfer performance. A total power loss of 180W (η=64%) is assumed as the heat generation reason within the motor, and the maximum temperature of 295°C is observed in the windings. The results show that approximately 58.1% of the total heat generated in the winding is dissipated radially via convection through the air-gap, and only 3.66% through the shaft via conduction. The thermal resistance for the shaft is in the range of 15-60 K/W and the rotor components is in the range of 0-2 K/W for the operational speed range of 0-2000rpm. Design manager study has been conducted to identify the performance of design parameters (Fins and air-vents) in cooling the motor. Air vents and external fins on rotor–lid (rotor cover) has a greater effect on cooling the motor than other design parameters. The modification of air vents and fins in generation of pressure drop in axial direction decreased the maximum temperature by 2% (6°C). A design concept for ad-joint optimization for improving the cooling performance has been proposed for the future research study.
Original languageEnglish
Article number2023-01-0760
Number of pages12
JournalSAE Technical Papers
Publication statusPublished - 11 Apr 2023
Event2023 WCX SAE World Congress Experience - Huntington Place, Detroit, United States
Duration: 18 Apr 202320 Apr 2023

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The authors wish to acknowledge GCRF (Global Challenge Research Fund) for supporting this work and Mubea Ltd for providing technical support and the CAD drawings of the motor.


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