Effect of surplus standing liquid on heat transfer resistance in the heat pipe (with mesh wick in a horizontal mode)

It is an engineering practice to fill a heat pipe with working fluid of a quantity a little larger than the clearance volume of the screen wick as the most desirable volume of working fluid is unknown. However, it is foreseeable that excessive volume of working fluid deteriorates the performance of the heat pipe. A new method is discussed of computation for heat flow and temperature distribution in a heat pipe with the assumptions that the depth of working fluid in the heat pipe can be calculated from the pressure losses in the evaporation and condensation zones, that surplus fluid adheres to the inner wall of the screen wick forming a cylindrical layer of liquid, and that the heat transfer resistance of the container, screen wick and cylindrical layer of working fluid are connected in series. To validate the computation, experiments were performed and good agreement was obtained.