Flow Assisted Evaporative Cooling for Electric Motor

Journal Article · 23 August 2021 · IEEE Transactions on Transportation Electrification

DOI: https://doi.org/10.1109/TTE.2021.3107505 · OSTI ID:1843430

Tikadar, Amitav ^[1]; Kim, Joon W. ^[2]; Joshi, Yogendra ^[2]; Kumar, Satish ^[2]

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1. Georgia Institute of Technology, Atlanta, GA (United States); Georgia Institute of Technology
2. Georgia Institute of Technology, Atlanta, GA (United States)

This paper examines a novel concept of flow assisted latent heat driven two-phase evaporative cooling (EC) confined in-between slot liner and active-winding of electric motor. Wicking micro-structure enhanced PDMS liner axially sucks coolant in the form of thin film between the PDMS liner and active-winding and eventually enables thin film evaporation on the outer surface of the active-winding. Therefore, EC based thermal management eliminates contact resistance between the winding and slot-liner and, enhances the heat extraction from the winding without compromising the electro-magnetic performance. Two-way coupled electro-magnetic (EM) – computational fluid dynamics/heat transfer (CFD/HT) and EM - lumped parameter thermal network (LPTN) models have been developed to assess the electro-thermal performance of the EC under steady and transient conditions. Taking a case study of a 125 kW jacket cooled BMW i3 motor and dielectric coolant FC-84, EC is shown to be capable of handling a maximum steady state rms current density of 26 A/mm2 at a evaporative heat transfer coefficient of 5,000 W/m2.K, which is about 78.7% higher compared to the traditional jacket cooling (JC). In case of EC, a maximum steady state and transient rms current density of 30 A/mm2 (106.2% higher compared to the JC), and 40.8 A/mm2 have been realized by using high thermal conductivity epoxy (1.9 W/m.K) impregnation material. Thermal performance of the EC is also assessed and compared with JC over a dynamic drive cycle. Lastly, a motorette testing has been performed to demonstrate the applicability of the proposed EC method and to validate the developed modeling framework.

• Research Organization: Georgia Institute of Technology, Atlanta, GA (United States)
• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• Grant/Contract Number: AR0001023
• OSTI ID: 1843430
• Journal Information: IEEE Transactions on Transportation Electrification, Journal Name: IEEE Transactions on Transportation Electrification Journal Issue: 1 Vol. 8; ISSN 2372-2088
• Publisher: IEEECopyright Statement
• Country of Publication: United States
• Language: English