Thermal Performance of an Axially Microgrooved Heat Pipe Using Carbon Nanotube Suspensions

摘要

An experimental investigation was carried out to study the heat transfer performance of an axially microgroovednheat pipe using water-based carbon nanotube suspensions as the working fluid. Experiments were performed undernthree steady operating pressures of 7.45, 12.38, and 19.97 kPa, respectively. Effects of the carbon nanotube massnconcentration and the operating pressure on the evaporation and condensation heat transfer coefficients, thenmaximum heat flux, and the total heat resistance of the heat pipe were investigated and discussed. Experimentalnresults show that carbon nanotube suspensions can apparently improve the thermal performance of the heat pipenand there is an optimal carbon nanotube mass concentration (about 2.0%) to achieve the maximum heat transfernenhancement. The operating pressure has a significant influence on the enhancement of heat transfer coefficients andnslight influences on the enhancement of themaximumheat flux.Under the pressure of 7.45 kPa, the evaporation heatntransfer coefficient and the maximum heat flux for the carbon nanotube suspension can be enhanced, at most, bynabout 80 and 25%, respectively, compared with those for water.