Thermal characteristics of conventional and flat miniature axially grooved heat pipes

A mathematical model describes the thermal properties of the conventional and flat miniature axially grooved heat pipes (AGHP). The model accounts for fluid circulation in the AGHP. The evaporator thermal resistance decreases and the condenser thermal resistance increases with an increase of the heat load. The maximum heat flux in the evaporator of copper-water flat AGHP is 25 and 50 watts/cm squared for horizontal orientation and vertical orientations. The capillary and boiling limitations check this maximum heat flux in the operating temperature range of 90 to 120 degrees celsius.