抄録
Recently, plate-type heat pipes called "Vapor Chamber" have been used to meet the increasing demand for the effective cooling of high-power CPUs and MPUs in personal computers, workstations and servers. The vapor chamber is fitted between the heat sources and the heat sink, which is much larger than the former, and works as a heat spreader to spread the heat generated from the heat sources to the larger heat sink, resulting in the lower thermal resistance between them. This paper describes the extensive numerical analysis on the fluid flow and heat transfer in the vapor chamber. The mathematical model of the vapor chamber is formulated. The modeled vapor chamber is a two-phase closed disk-shaped chamber, which consists of the vapor region, the liquid-wick region and the solid wall region. The heat flux is supplied from a heat source to a part of the bottom of the vapor chamber, and the top of the vapor chamber is cooled by a heat sink. The equations of continuity, momentum and energy for each region are derived and solved numerically with proper boundary conditions. First, the numerical results are compared with the experimental results. As the numerical results agree well with the experimental results, the validity of the present numerical analysis is confirmed. Secondly, by the numerical analysis, the effects of the heat source size and the liquid flow in the wick on the numerical results of the temperature distribution in the vapor chamber are discussed.
