Graduation Semester and Year
Summer 2024
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Mechanical Engineering
Department
Mechanical and Aerospace Engineering
First Advisor
Dereje Agonafer
Second Advisor
Miguel Amaya
Third Advisor
Amir Ameri
Fourth Advisor
Abdolhossein Haji-Sheikh
Fifth Advisor
A S M Raufur Chowdhury
Abstract
The body of work that comprises this dissertation is divided into two main sections. The first section is regarding novel heat sink and cold plate designs that leverage a metal additive manufacturing process called electrochemical additive manufacturing (ECAM) to drive increased thermal performance. The continuous advancements in electronics computational capabilities have resulted in ever-increasing thermal loads at the component and data center server level. These strides within the field are soon to be compounded by the rise of artificial intelligence and machine learning technologies. Traditionally, high performance electronics components have been able to be cooled by forced-air cooling; however, the computational performance increases have begun pushing the boundaries of air cooling, necessitating the use of alternative, more effective, cooling methods. Of those methods, direct-to-chip liquid cooling using cold plates and single-phase immersion cooling have proven to be amongst the most effective techniques. This section is comprised of two individual studies, one that is focused on direct-to-chip liquid cooling and another that is focused on single-phase immersion cooling. The direct-to-chip liquid cooling study details a comprehensive computational fluid dynamics (CFD) analysis on cold plates which are producible only by additive manufacturing methods. The purpose for this study is to provide a comparison of six ECAM cold plate designs against traditional cold plate counterparts which are producible by conventional manufacturing methods, evaluating thermal performance and pressure drop of the fluid flow using CFD analysis. For the single-phase immersion cooling study, heat sinks with triply periodic minimal surface lattice structures were designed for application in single-phase immersion cooling of data center servers. The objective is to compare various heat sink geometries by minimizing max case temperature in a single-phase immersion cooling setup for a natural convection application.
The second section is focused on experimentally characterizing the density as a function of temperature for several commonly-used paraffin wax phase change materials (PCMs). PCMs are materials that have the ability to absorb a substantial amount of heat during phase transition from solid to liquid, and therefore prove to be useful in thermal energy storage. The density of paraffin wax PCMs is largely dependent on temperature, and during the phase change process, the density decreases dramatically as the PCM transitions from solid to liquid. Consequently, the PCM experiences dramatic volumetric expansion during this transition. Besides the thermal energy storage uses of PCMs, this volumetric expansion that they exhibit is also used in thermal actuator applications, often referred to as wax motors. While density of PCMs does affect their thermal and mechanical performance, such as volumetric heat capacity, the property is not well-characterized within the literature. In this study, we examine ten paraffin wax PCMs with varying melting temperatures and characterize their densities as a function of temperature. This characterization was done using a piston and cylinder dilatometer test setup within a temperature-controlled thermal chamber that we designed and validated to the well-characterized density properties of water. The density and temperature relationships were further analyzed using piecewise linear regression analysis to develop mathematical models of density as it relates to temperature, which will be useful to those wishing to analyze designs in which PCMs are used, such as in PCM-filled heat sinks.
Keywords
Cold Plate, Direct-to Chip Liquid Cooling, Data Center Cooling, Single-phase Immersion Cooling, Heat Sink, ECAM, Phase Change Material, Paraffin Wax, Thermal Energy Storage, Thermal Management
Disciplines
Heat Transfer, Combustion
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Lamotte-Dawaghreh, Jacob, "Design and Analysis of Electrochemical Additive Manufacturing Based Cold Plates and Heat Sinks for Enhanced Electronics Cooling and Temperature-Dependent Density Characterization of Phase Change Materials" (2024). Mechanical and Aerospace Engineering Dissertations. 257.
https://mavmatrix.uta.edu/mechaerospace_dissertations/257