Heat-Transfer Characteristics in Screen-Wick Heat Pipes

抄録

Heat-transfer coefficients and maximum heat-transfer rates due to capillary limitation were investigated in horizontal heat pipes with stainless-steel screen-wicks, using water as a working fluid. The heat transfer coefficients in a condenser can be estimated by the equation of heat transfer across the liquid-saturated wick. The liquid-vapor interface in an evaporator seems to terminate between the first and second layers from the heated wall. For prediction of the maximum heat-transfer rate, it is important that the capillary radius, permeability and porosity are evaluated accurately. Thus, the capillary radius and permeability were measured experimentally. Also, an equation for porosity was proposed. Using the value obtained above, the recess of the liquid-vapor interface has to be taken into account. Consequently, the calculated maximum heat-transfer rates agree with the experimental ones within a ±20 percent error.