Building A Passive Thermal Management System Using Phase Change Material Embedded In Porous Media

A Master of Science thesis in Mechanical Engineering by Mohammed H. A. Azzam entitled, “Building A Passive Thermal Management System Using Phase Change Material Embedded In Porous Media”, submitted in December 2021. Thesis advisor is Dr. Mohammad O. Hamdan. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).

Abstract

This work aims to investigate the heat transfer effectiveness of different phase change materials (PCMs) when infused in plate-based heatsinks with a fixed volume fraction of thermal conductivity enhancer (TCE). Moreover, this work examines the impact of a metallic wire mesh infused with PCM. The metallic wire mesh is modeled using porous media theory. The study is conducted using numerical simulation via a commercial tool (ANSYS-Fluent). The PCM’s ability to absorb and release large amounts of thermal energy at constant temperature is a desired feature in transient electronics cooling. During electronics operation, large amounts of heat are generated. Improper dissipation of this heat causes electronics to overheat. Overheating causes a decrease in the performance, reliability, and life expectancy of these devices. Heatsinks integrated with PCMs offer a prospective cooling solution for transient high-performance electronics such as aircraft electric switches and computer processors. Peak usage of aircraft electrical switches occurs during aircraft takeoff and landing, which produces large amounts of heat in a short time. This rapid heat release is responsible for most aircraft electrical fires. As the aerospace industry evolves toward fully electric aircraft and electronics become more compact, undesired heat generation is growing dramatically and needs to be thermally mitigated. This study begins by examining 2-D models of heatsinks filled with different PCMs. These models are a heatsink with no fins, a plate-fin heatsink with two fins, and a plate-fin heatsink with four fins. These heatsinks are examined for three PCMs: Salt Hydrate, Paraffin Wax, and RT35. Next, a wire mesh infused with a PCM is examined to understand the impact of wire-mesh porosity and permeability on the transient thermal performance of a PCM heatsink.