Abstract
In recent years, with the ever-changing nature of technology, the electronic components develop toward miniaturization, concentration, and high operational efficiency. This fact makes the heating density inside the electronic components increase significantly. Thus, there is a problem about heating dissipation inside a narrow space. Nucleate pool boiling is an effective phenomenon of heat transfer. It is composed of many complicated boiling mechanisms. This fact makes it has a very heat transfer coefficient. The heat transfer coefficient of nucleate boiling vary with the heater surface conditions, such as orientation, size and working fluids. The surface orientation is an important parameter on the heat dissipation technology. The purpose of the present study is to clearly understand the influence of heater orientation on nucleate pool boiling. The photograph of bubble behaviors will be shot by high speed camera to analyze the parameters which took the lead on nucleate pool boiling: Nucleation site density, Bubble departure diameter, and Bubble departure frequency.