Investigation On New Integrated Heat Sink With Heat Pipes

In recent years, with the increase in integral density and performance and the decrease in size for CPU of PC, heat flux is critically high. So the heat dissipation has become the bottleneck in development of CPU. As a two-phase heat transfer device, heat pipe can transport a considerate quantity of heat with a very small temperature difference from evaporation section to condensing section, so heat pipe is widely applied to the field of high heat flux due to its intrinsic merits such as superior conductivity, surface temperature uniformity, high efficiency of heat transfer and compact and adaptable structure, ect. Therefore, heat sink with heat pipes has become the trend of CPU cooling in the future.At first, the technology for CPU cooling and the development of heat sink using heat pipe for CPU were summarized in this paper. Then, the operating principle and the main thermal resistances of heat pipe introduced briefly. In view of the disadvantage of the heat sink using heat pipe for CPU cooling in the market, two new structure of heat pipe heat sinks were brought forward: single-tube flat-flexed integrated heat pipes [SFIHP] and multi-tube flat-flexed integrated heat pipes [MFIHP], which have many advantages, such as high heat dissipate efficiency, simple structure, low contact thermal resistances, light weight, low cost and so on. The method of CFD numerical simulation is employed to simulate the exterior fluid field of the two new types of heat pipe heat sinks and determined the structure and size of FBSIHP. At the same time, after the simulated to the exterior fluid field of the same cross section area round heat pipes and ellipse heat pipes which have equal cross section area. In conclusion, the advantage of the ellipse heat pipes was approved which point out the direction for the determination of the MFBSIHP structure and size.After the investigation about the heat pipe on the forward in the paper, one FBSIHP model was made. According to GB/T 8446.2-2004, an experimental system was established to test heat transfer performance of FBSIHP. A heat pipe filling system was set up also. The temperature uniformity of the surface of the FBSIHP and the influence in different working fluid filling, different working fluid and different air upwind velocities was tested in the paper. In conclusion, the tests show that the FBSIHP can adapt 200W CPU heat cooling completely.