Effects of Multiple Sintering Parameters on the Thermal Performance of Bi-porous Nickel Wicks in Loop Heat Pipes

The thermal performance of a water-saturated Loop Heat Pipe (LHP) with bi-porous nickel wicks has been examined theoretically and experimentally, based on five key influencing factors including the content of foaming agent, compacting pressure, incubation time at suitable temperature, sintering temperature and particle size of foaming agent. Comparison was made among a total number of 20 tests with each influencing factor allocated by four different values, where porosity, permeability, capillary suction head and effective thermal conductivity (ETC) were examined. ETC is an important parameter of thermal performance, and its experimental values were compared with eleven theoretical models. The results showed that ETC was mostly affected by the content of foaming agent: 1.9-2.2 times compared to the effect of compacting pressure and incubation time, with the effect of sintering temperature and particle size of foaming agent ata underestimated the true ETC values. In the porosity range of 0.5-0.7, an average of the Chernysheva & Maydanik model and the Chaudhary & Bhandari model was found to be the best fit to the experimental data, providing an accurate method to predict ETC values of water-saturated LHP with bi-porous nickel wicks.