The Theory Of Micro Heat Pipe Essay

The Theory Of Micro Heat Pipe Essay

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Heat pipes are passive heat transfer devices that can transfer heat at high rates over large distances with extremely small temperature drops without the requirement of external pumping power. They are commonly used for high heat flux applications because of an increased effective conductivity of the material. The basic working of a heat pipe is dependent on the capillary pumping of the fluid from the cold end to the hot end using a wick or a wickless design. Liquid is evaporated at the heated end, the vapor then travels back to the cold end where it condenses and is then recirculated back to the hot end by capillary pumping.
The concept of micro heat pipe was first published by Cotter in 1984 [1]. Since then, many papers and books have been published understanding the working of a heat pipe. The equations, their operation and the limitations associated with the heat pipes are well developed [2, 3]. Peterson [4] and Faghri [5] have written excellent reviews about the advances in numerical modelling, analysis and experimental simulation of different types of heat pipes. Khrustalev and Faghri [6] developed a detailed mathematical model describing the distribution of the liquid in a micro heat pipe and its thermal characteristics. Swanson and Peterson [7] formulated a thermodynamic model of the vapor-liquid interface to provide a fundamental insight into the critical mechanisms for proper micro heat operation. Babin et al. [8] and Longtin et al. [9] have also developed steady state models to predict the operating parameters of a micro heat pipe. Bowman et al. [10-12] developed a simple model of comparing the efficiency and thermal performance of a heat pipe with a solid fin using a lumped inside heat transfer coefficient. They provi...

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... reaches its peak and further penetration down the axis of the heat pipe is arrested and this phenomena is defined in this paper as ‘arresting phenomena’. Arresting phenomena is verified by a simple, one dimensional, thermal fluid model. The model also gives us an insight on the temperature signature associated with the flooding limitation and the characteristics of the interfacial flow. A simple, one dimensional model is used to calculate the internal heat transfer coefficient of the heat pipe and verify the arresting phenomena. In the supplemental information, a model to calculate the chemical potential per unit volume is used to describe the interfacial effects observed near the heater end. The model suggests presence of superheated vapor in the region near the heater end leading to condensation and confirms the results from thermal and fluid models in the paper.

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