An integrated heat pipe coupling the vapor chamber and two cylindrical heat pipes with high anti-gravity thermal performance

An integrated heat pipe (IHP) coupling the vapor chamber and two cylindrical heat pipes is proposed in this study. Cylindrical heat pipes were connected with the top surface of the vapor chamber to extend the area of the condenser. The copper powder rings and graded pore-size wick are used to shorten the circulation path of working fluid and strengthen the capillary pressure and wick permeability of the wick structure. The effect of various filling ratios (30%, 40%, 60%, and 80%) and different inclination angles (0 degrees, 90 degrees, and 180 degrees) have been investigated experimentally. The results showed that the filling ratio has a significant impact on the heat transfer performance of IHP, and the high filling ratio IHP shows better thermal properties. Specifically, the maximum temperature is lower than 83 degrees C at the heat load of 150 W when the filling ratio is 60%. Moreover, the integrated heat pipe shows better anti-gravity thermal performance than a conventional heat pipe. The lowest anti-gravity thermal resistance is 0.157 K/W with a heat load of 80 W. As compared with other heat pipes reported in this literature, the IHP has a good thermal performance and can adapt to many inclination angles.