Thermal Performance of a Vapor Chamber Heat Pipe with Diamond-Copper Composition Wick Structures

The vapor chamber heat pipe has the potential in the challenging areas to be employed as a heat spreader for cooling of high-performance microchips. This is due to not only the thickness of vapor chamber is in order of mm scale but also both the weight and the thermal resistance are less than the conventional copper heat spreaders. The operation principle of vapor chamber heat pipe is well understood and earlier studies show that the performance of vapor chamber strongly depends on the wick materials and structures. Conventional wick structure is made of sintered copper powers or base plate with micro-grooves, present work provide a novel wick design with various diamond-copper compositions to boost the effective thermal conductivity. There are three types of diamond-to-copper powder volume ratio as 1∶4, 1∶6 and 1∶8 considered in fabrication of the wick sheets and columns. An infra red (IR) thermal image camera is used to measure the steady and transient temperature distributions of the top evaporator surface of the vapor chamber by placing a single heat source with varied heat flux inputs. For performance comparison, the experimental measurements were also conducted on a solid copper block and an identical vapor chamber heat pipe with sintered copper powders of similar dimensions. Generally, the present wick material of diamond-copper composition can effectively prevent this shortcoming of dry out at high heat flux. Moreover, results also show that IR thermal imaging is a quick and effective technique for evaluating the thermal performance of vapor chamber heat pipe.