Numerical and Experimental Study of the Effective Parameters on the Thermal Performance of Straight Circular Heat Pipes with Double-Ended Cooling with Middle Evaporator

The heat pipe is an efficient heat transfer device and can transfer large amounts of heat with a small temperature difference between the hot and cold sources quickly. In the present study, a two-dimensional numerical simulation method was used to analyze the thermal performance of heat pipes with double-ended cooling with the middle evaporator and to investigate the effect of operating conditions, wick and retaining chamber characteristics on it. The governing equations were discretized by ANSYS Fluent software and then solved using suitable boundary conditions. The wall temperature profile of the heat pipe was obtained. Then, to validate the results and to investigate the effect of using two condensers on the thermal resistance of the heat pipes, an experimental apparatus was used. Numerical results were compared with the valid numerical and experimental results that had very good and acceptable accordance. The results showed that the heat pipes with double-ended cooling with a middle evaporator had a lower thermal resistance than conventional heat pipes. The amount of thermal resistance increased with increasing the thickness and porosity of the wick. However, increasing the evaporators and condensers length, as well as increasing the thickness and internal diameter of the retaining chamber, reduced the thermal resistance. The results also showed that the heat pipes, which the materials with higher thermal conductivity were used in their wick and retaining chamber's manufacturing, had a lower thermal resistance. Finally, it was found that the increase of thermal power had no significant effect on the thermal resistance.