Investigation of temperature fluctuations caused by evaporating meniscus instabilities in two-phase heat transfer devices

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The evaporation of a liquid thin film formed in a porous structure and its stability are governed by a complex interaction of mechanisms and among the most challenging problems to study. Our primary goal is to improve the current fundamental knowledge in this field, and thus, to develop the required tools for solving industrial problems involving thin-film evaporation. A better understanding of the underlying physical mechanisms of these phenomena is critical to further improvements in a wide variety of applications, including electronics, fuel-cell, and chemical processing industries.***One of the important areas of application is the thermal control of power generating equipment. As new electronic devices are producing more power and also getting smaller, it is becoming more difficult to remove excess heat by using conventional cooling techniques. High operational temperatures can reduce the life time of electronics, cause performance anomalies and device failures. Therefore, there is a need for more efficient thermal cooling technologies. The most efficient thermal control devices currently available, such as heat pipes, loop heat pipes, and vapor chambers, rely on the evaporation of a liquid thin film. These devices have been used to transfer excess heat from a heat-producing component such as a microprocessor in a computer or an instrument in a spacecraft, while maintaining the temperature within a specified range. The advantages of these devices over other cooling techniques include lack of moving parts, robustness, and the ability to transfer large amounts of heat. ***However, some operational aspects of these devices are still not well understood. One of the major problems associated with these devices is the undesirable temperature fluctuations. Because of the complex phenomena taking place in these devices, mostly qualitative explanations have been proposed for origin of these fluctuations. The temperature fluctuations are highly undesirable as they may hinder the heat removal capacity or cause costly failures.***An improved understanding of the thin-film stability will allow us to investigate the origin of the fluctuations and propose design solutions to ensure a stable operation of these devices. Our previous research has also shown that although the interface instabilities are mostly undesirable, it is feasible to develop new heat transfer enhancement techniques by taking advantage of the instabilities. This is a highly promising area of research and deserves to be further investigated in more detail.***The research will be carried out through both experimental and numerical investigation and involve training of two PhD and two MASc students. The important application areas include electronics cooling, passive cooling of nuclear reactors after an emergency, and thermal control of sensitive space payloads.