Date of Graduation

5-2022

Document Type

Thesis

Degree Name

Bachelor of Science in Mechanical Engineering

Degree Level

Undergraduate

Department

Mechanical Engineering

Advisor/Mentor

Huitink, David

Committee Member/Reader

Walters, Keith

Abstract

Power electronics are necessary to convert power from DC sources for AC applications. As this technology trends toward smaller packaging for denser power loads, the increased electrical losses result in deleterious excess heat. Thermal management devices are required to prevent the effects of thermal runaway from shortening the longevity of these modules. Nonmetallic jet impingement heat spreaders provide several benefits in terms of weight and performance over conventional cold plates while not accentuating EMI from the switches in the power module; however, the polymer makeup of the materials previously used for fabricating these devices raises durability concerns under the high heat and pressure environments of operation. Therefore, single-nozzle samples were tested under parameters designed to accelerate the degradation of the nozzles key to the thermal performance of the jet impingement heat spreader with the objective of characterizing the degradation of these nozzles over time. Samples were fabricated using direct additive manufacturing of ABS and nylon along with sacrificial casting around a 3D printed internal geometry for epoxy samples. Samples were tested for extended durations under non-cavitating flow and shorter durations under cavitating flow. The epoxy and nylon samples handled both cavitating and non-cavitating flow well, with minimal pressure drop alteration or widening at the nozzle throat. On the other hand, ABS could not withstand the high temperature of the coolant for extended periods and failed extensively under high cavitation flows. Thus, nylon and epoxy are the most suitable materials for future heat spreader fabrication.

Keywords

Jet impingement, power electronics, thermal management

Available for download on Thursday, May 01, 2025

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