Surface Temperature Effect on Convective Heat Transfer Coefficients for Jet Impingement Cooling of Electric Machines With Automatic Transmission Fluid: Paper No. IPACK2019-6457

Research output: Contribution to conferencePaper

Abstract

In this study, the results of NREL's continued work on experimental characterization of the thermal performance of free-surface jets of automatic transmission fluid impinged on a heated target surface are presented. The measured heat transfer coefficients are useful for understanding factors influencing performance of driveline fluid-based cooling systems for electric machines and help designers in developing high-performance, power-dense and reliable machines. Experiments were carried out for different fluid and target surface temperatures (50 degrees C, 70 degrees C, and 90 degrees C for the fluid and 90 degrees C, 100 degrees C, 110 degrees C, and 120 degrees C for the target surface). Impinging jet velocities (0.5 m/s to 7.5 m/s) and the jet position on the target surface (center versus edge) were also varied. The impinging angle was kept at 90 degrees relative to the target surface. It was found that higher target surface temperature increased heat transfer coefficients, namely, increasing surface temperature from 90 degrees C to 120 degrees C enhanced heat transfer coefficient values at higher impinged jet velocities (7.5 m/s) by up to 15%.
Original languageAmerican English
Number of pages7
DOIs
StatePublished - 2019
EventASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - Anaheim, California
Duration: 7 Oct 20199 Oct 2019

Conference

ConferenceASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems
CityAnaheim, California
Period7/10/199/10/19

Bibliographical note

See NREL/CP-5400-74284 for preprint

NREL Publication Number

  • NREL/CP-5400-76106

Keywords

  • automatic transmission fluid
  • electric machines
  • electric motors
  • jet impingement
  • thermal management

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