Numerical Investigation of Thermosyphon Heat Pipe Thermal Performance

Abstract

Thermosyphon a two phase heat pipe is an effective thermal transport technology in high technology cooling of electronics to renewable energy technology. In this study, numerical simulation of thermal performance of a thermosyphon to addresses the temperature field and thermal resistance equivalent to the thermal conductivity. Simulations reported that the time taken in initiation of a start up to reach steady-state conditions increases up to 25 percent with increase in the fill ratios and 40 percent increase in tube dimensions. Conversely, when heat flux through start-up section evaporators was high, decrease of 35 percent in start-up time was realized. Also, the length-diameter, liquid-column-height-diameter ratio, and input heat rate were observed to significantly influence equivalent thermal resistance. Increase of 50 percent in the heat transfer rate, the thermal resistance drops by 15percent, whereas the thermal resistance rises by 20 percent in case the height ratio of the liquid column exceeds its optimum. Also proved that smaller tubes in the range of the analyzed set are going to be more efficient where the thermal resistance decreased by 12 percent compared to bigger ones under the same conditions. Best fill ratio of 70 percent was found and this gave rise to a thermal resistance that was minimal, whereas deviation of it will lead to a resistance increase of 18 - 25 percent. These results provide a foundation to the strategic optimization of thermosyphon designs, based on the parameter manipulation of the design to achieve optimal heat transfer and reduction in the thermal resistance.