Accession Number:

AD1120524

Title:

Phase Change Materials for Vehicle and Electronic Transient Thermal Systems

Descriptive Note:

[Technical Report, Doctoral Thesis]

Corporate Author:

DEVCOM Army Research Laboratory

Personal Author(s):

Report Date:

2020-12-20

Pagination or Media Count:

492

Abstract:

Most vehicle environments are transient in nature, yet traditional thermal solutions address peak load conditions with steady-state designs. The overdesigned subsystems that result increasingly cannot meet target size, weight and power demands. Phase change thermal storage promises to buffer thermal transients while providing a functional system energy reservoir. Despite significant research, few phase change material PCM solutions have transitioned out of the laboratory. This work explores the state of PCM research for vehicle and electronic applications and develops design tool compatible PCM models for electronics packaging. This thesis includes a comprehensive PCM review of over 700 candidate materials across a number of material classes, followed by a transient vehicle thermal systems analysis. Promising materials are identified for improving emissions, energy efficiency, and thermal protection, and future research recommendations focus on improving data collection and material metrics while increasing research on metallic and solid-state PCMs for high-speed applications. Following the review, electronics packages are shown using finite element based thermal circuits to exhibit both worsened transient response and extreme convective insensitivity under select pulsed conditions. Both characteristics are quantified analytically and numerically, and it is demonstrated that convective insensitivity can be quantified using package thermal Elmore delay. Design level PCM-package models are developed using an energy conservative polynomial smoothing function for enthalpy based phase change methods. Two studies use this to examine PCM-integrated electronics packages substrate integrated Thermal Buffer Heat Sinks, and direct on-die PCM integration using new phase change thermal circuits. Both show effective thermal buffering, but only metallic PCMs exhibit significant sub-millisecond temperature suppression which cooling or package integration alone could not address.

Subject Categories:

  • Thermodynamics

Distribution Statement:

[A, Approved For Public Release]