Thermal analysis of optimally designed inclined micro heat pipes with axial solid wall conduction

The effect of gravity on the thermal performance of inclined micro heat pipes with axial conduction in the solid wall is reported. A one-dimensional, steady-state model is developed from first principles in which the continuity, momentum, and energy equations of the liquid and vapour phases, together with the Young–Laplace equation, are solved numerically to yield the heat and fluid flow characteristics of an inclined micro heat pipe which is operated optimally at a certain operating temperature. The analysis covers both the favourable and adverse effects of gravity on the performance of a micro heat pipe. The effects of gravity, through the angle of inclination, on the heat transport capacity, the optimal charge level of the working fluid, the liquid volume fraction distribution, the circulation strength of working fluid and the solid wall temperature distribution are analysed, to provide a better insight for the design of inclined micro heat pipes.