Numerical Study of a Frustum-Shaped Wick Heat Pipe at Low Power Input

Heat pipes are highly efficient heat transfer devices utilized in mechanical engineering and robotics. They operate by exploiting the phase change of a working fluid to transfer heat from a hot source to a cooler sink. A significant challenge for these systems is to reduce their size and cost while ensuring that performance remains uncompromised. To this aim, this study investigates the thermal performance of novel frustum-shaped heat pipes through numerical simulations using COMSOL Multiphysics. Firstly, four different geometries are evaluated, including conical and frustum vapor cavities with the evaporator and condenser sections positioned at the smaller or larger diameter ends. These geometries are compared against a conventional cylindrical heat pipe design. Governing equations for fluid flow and heat transfer in the vapor cavity and porous wick structure are solved under constant heat input and constant temperature boundary conditions at the evaporator. Steady-state temperature distributions and heat transfer rates are analyzed to evaluate the thermal resistance of each geometry. Results indicated that while the cylindrical design achieves the lowest overall thermal resistance due to its greater fluid capacity, certain frustum geometries, such as the Frustum-condenser case, demonstrate competitive thermal performance, especially in terms of pressure drop. The findings provide insights into optimizing heat pipe geometries for applications with space constraints or specific thermal management needs. This numerical study highlights the potential of shape modification as an effective approach to enhance heat pipe capabilities.