Theoretical Analysis of the Maximum Heat Transport in Triangular Grooves: A Study of Idealized Micro Heat Pipes

A mathematical model for predicting the minimum meniscus radius and the maximum heat transport in micro heat pipes is presented. In this model, a theoretical minimum meniscus radius was found and used to calculate the capillary heat transport limit based on the physical characteristics and geometry. A control volume technique was employed to determine the flow characteristics of wickless micro heat pipes, and incorporate the effects of the frictional vapor-liquid interaction on the liquid flow. Unlike previous models, this model for the first time considers the true characteristics of micro heat pipes to determine the minimum meniscus radius and the maximum heat transport capacity. In order to compare the heat transport and flow characteristics, an effective hydraulic diameter was defined and the resulting model was solved numerically. The results indicate that the heat transport capacity of micro heat pipes is strongly dependent on the apex channel angle of the liquid arteries, the contact, angle of the liquid flow, the length of the heat pipe, the vapor flow velocity and characteristics, and the tilt angle. In addition, the analysis presented here provides a mechanism, which for a given set of conditions, allows the geometry to be optimized and a micro heat pipe designed with a maximum heat transport capacity. This investigation will help optimize the design of micro heat pipes, making them capable of operating at increased power levels with greater reliability.