EFFECT OF SCREEN LAYERS AND ORIENTATIONS ON MESH WICKED HEAT

Thermosiphons utilize gravity, thermal conduction, and convection to achieve desired cooling. On the other hand, wicked heat pipes are different versions of heat pipes that employ capillarity to overcome any gravitational limitations. Mesh screens provide additional pumping to enhance the thermal cycle within the heat pipe. In this paper, an experimental study is carried out to compare the thermal performance of an empty copper pipe, a traditional thermosiphon, and two wicked heat pipes with different numbers of mesh screen layers. The comparison of the thermal performance is done through measuring the thermal resistivity, thermal conductivity, and heat transfer coefficient of the pipes at steady state. Then, the corresponding nondimensional parameter, the Nusselt number, is calculated to relate the conductive and convective abilities of the pipes. With an identical percentage fill of 50%, the heat pipes are subjected to five different heat loads and five different orientations. Theoretically, the layers of mesh screens enhance the heat transfer, and the pipes perform best at the vertical position. The wicked heat pipes perform better than the copper tube and thermosiphon at any orientation. Furthermore, the mesh wicked heat pipes show an identical performance when they are rotated by 180°