Effect of Prescribed Boundary Conditions on the Condenser Behavior of Grooved Heat Pipes

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2022-2

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Pourabdollah Vardin, Ali

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Rapid enhancements in electronic microchips bring the need to design and manufacture advanced cooling devices which can operate effectively without external source. Passive heat exchangers like heat pipes can remove a remarkable amount of heat with the help of capillary action. The phase change process in heat pipes, which utilizes the latent heat energy, enables high heat transfer rate over small temperature differences. Although the physics of evaporation in grooved heat pipes is understood, and comparatively satisfactory models are present, the condensation, on the other hand, is more complex and still requires a better physical understanding to facilitate the development of realistic models. This study investigates the effect of two different sets of boundary conditions on forming liquid-vapor interface film on the fin top of grooved heat pipes. The validation results reveal that the boundary conditions at the fin edge can change depending on the edge angle and the temperature difference between the vapor and liquid. Also, the impact of disjoining pressure on the solution domain and film profile is explored, which shows that inclusion of the effect of disjoining pressure can limit the solution domain, and beyond a specific edge angle, a solution cannot be obtained. Moreover, the current study presents a novel numerical approach based on a modified finite difference method to solve the governing non-linear fourth-order differential equation. This novel approach provides a chance to model the two-dimensional flow on the fin top, which has not been studied in the literature yet. The primary findings of the two-dimensional model suggest that the axial flow is negligible compared to the lateral flow on the fin top except for a small region near the centerline.

Subject Keywords

Condensation, Disjoining pressure, Numerical simulation, Grooved heat pipes, Two-dimensional flow

URI

https://hdl.handle.net/11511/96347

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

A. Pourabdollah Vardin, “Effect of Prescribed Boundary Conditions on the Condenser Behavior of Grooved Heat Pipes,” M.S. - Master of Science, Middle East Technical University, 2022.