Fabrication of sintered wick in micro -grooved pipe
The sintering heat pipe is an ideal component in solving the heat dissipation of high heat flux chips. The heat pipe with sintered wick structure in micro-grooved pipe was featured with low heat resistance, high bond strength and hard to dryout. According to the sintering theory, the manufacturing process of sintered wick could be divided into four phases: reduction phase, sintering starting phase, sintering preservation phase and sintering cooling phase. The sintering temperature, sintering time and sintering atmosphere about fabrication of the innovative sintered wick were also inspected. The result was discoveried that 100 mesh spherical copper powders had high porosity and low radial shrinkage at the sintering temperature of 950°C for 3 hours and the mandrel could be easily pulled out. It was also found that the oxidation reduction process could manufacture new micro structure—the segmentation cracks structure on the surface of copper powders.
Thermal performance of sintered miniature heat pipes
Abstract Investigation has been carried out on the thermal performance of sintered miniature heat pipes with 3 mm outer diameter. In the theoretical analysis, the influence of wick structure parameters is determined by using the theory of capillary limitation. As a result, the degree of importance is found to be as follows: porosity, powder diameter and thickness of wick structure. In the experiments, heat pipes with sintered dendritic copper powder wicks were fabricated and tested. The maximum heat transfer rate is about 13 W with an effective heat pipe length of 20 cm. By adopting the formulae developed for both sintered spherical powder and fiber and adjusting their proportion, the agreement between experimental results and prediction is found to be quite good in the tested operation temperature range.
The Challenges of Electronic Cooling: Past, Current and Future
This paper represents my personal recapitualation of my 4 decades of continuous involvement in all phases of electronic cooling, from conceptual design, through engineering development to product implementation. The cooling designs that we applied successfully in the past are reviewed chronologically. The challenges we are currently facing are also discussed and an attempt is made to forecast the challenges that will confront the electronics cooling community in the near and distant future. The paper includes a summary of IBM sponsored research spanning a period of 25 years at 12 universities on a wide range of topics related to electronic cooling technology.Copyright © 2003 by ASME