Enhanced Thermal Management in High-Temperature Applications: Design and Optimization of a Water-Cooled Forced Convection System in a Hollow Cuboid Vapour Chamber Using COMSOL and MATLAB

TL;DR

This work addresses efficient heat dissipation for high-temperature energy conversion devices operating in the 700–1000 K range to enable waste-heat recovery with thermoelectric generators (TEGs). It develops water-cooled forced convection systems inside a hollow cuboid vapour chamber and optimizes geometry using both parametric sweeps and density-based topology optimization in COMSOL and MATLAB, with the objective of minimizing the design-space temperature gradient $f_{obj}(\Omega) = \int_{\Omega} k (\nabla T)^2 d\Omega$. Parametric results identify an 18-fin configuration as highly effective, while topology optimization yields a interior-dense topology around ~35% density that provides strong heat spreading; time-dependent COMSOL studies show the system can cool from 1000 K to 548.29 K within 3 s, yielding an estimated TEG efficiency around $12.4\%$ (potentially up to $33\%$ under pulse operation). The study discusses trade-offs between manufacturing practicality and cooling performance, and proposes integrating Miscibility Gap Alloys (MGA) for high-temperature heat storage to enable staged TEG power generation in coal-fired power plants. Overall, the work demonstrates viable, design-paths to enhance high-temperature heat dissipation and enable effective waste-heat utilization with TEG systems.

Abstract

This report details the design and optimisation of a water-cooled forced convection heat dissipation system for use in high-temperature applications (ranges between 700 degrees - 1000 degrees K). A hollow cuboid vapour chamber model was investigated. The space within the hollow cuboid was used as the design space. COMSOL, a FEM software product was used to solve for the physical parameters of each geometry for the heat dissipation system design space. COMSOL in conjunction with MATLAB was used for the parametric and density-based topology optimisation of the geometric design in the design space. The goal of the optimization is the minimisation of a temperature gradient over the design space. This allows the heat to be evenly spread throughout the designed mesh which allows for more effective cooling. To reduce the computational time needed to solve and optimise each geometry in 3D, a 2D representation was created for the front and rear faces of the hollow cuboid setup. These 2D face designs were then extrapolated into 3D over the length of the hollow cube and COMSOL was used to find a solution for each model. This report also proposes a use case for this system wherein it would be used in conjunction with MGA and thermometric technology within coal-fired power stations for the extraction and storage of waste heat for later use.

Figures (52)

• Figure 1: Detailed 2D view of TEG with heat dissipation system at bottom modified from FOM
• Figure 2: simple 2D view of general setup for power generation system showing heat dissipation system
• Figure 3: Detailed 2D view of vapour chamber showing hollow design space
• Figure 4: Comparison of surface area vs volume of shapes
• Figure 5: Detailed 3D view of the hollow cuboid vapour chamber. Note that a cut has been taken out of the chamber to show the inner vapour space. The TEG module is shown below in red.