Experimental Study on Thermal Performance of Aluminous Vapor Chamber

Abstract

In this paper, a large size aluminous vapor chamber (650 mm × 350 mm × 5 mm) with high effective thermal conductance and light weight was developed for heat dissipation of high heat flux point heat source in aircrafts near space. The heat performance of aluminous vapor chamber (VC) was tested in a power range of 50 W to 159 W. The heat resistance is about 0.2 ℃/W under a heat flux of 25 W/cm2, and the chamber works normally without dryout under a power condition as high as 159 W (~43 W/cm2), which indicates its capability under high heat flux. To enhance thermal performance of aluminous vapor chamber, an integration heat spreader which integrated of advanced carbon materials (annealed pyrolytic graphite, multilayer graphene) and aluminous vapor chamber was fabricated. The test result shows integration heat spreader can significantly reduce the heat spreader resistance of aluminous vapor chamber: the temperature difference between the evaporator section and condenser section decreases from 39.6 ℃ to 9 ℃ under a heat rate of 130 W (heat flux 36.5 W/cm2), while the heat resistance reduces from 0.3 ℃/W to 0.07 ℃/W. Also, the effect of gravity has been studied under horizontal placement and vertical placement. The result shows the thermal resistance under vertical placement is about 3–4 times of that under horizontal placement.