Abstract
AbstractThis study used de-ionized water that was provided by syringe pump as work fluid. The two-phase flow visualization under a high speed digital video camera which mounted with a microscope. The temperature of inlet and outlet reservoirs, inlet pressure as well as the pressure drop during experiments were recorded and analyzed with flow visualization. We used these data to study the mechanism of boiling heat transfer and two phase flow in microchannels.For this study, the bubbles’ growth rates are about 0.04~20 mm/sec. It’s much slower than traditional large scale of the same heat transfer condition. Furthermore, the bubbles’ growth rates present as linear growth with time increasing. That doesn’t agree with Cooper’s report that bubbles grow corresponding to radical time increasing. The variations of pressure in microchannels will significantly effect on the bubbles departure size and on the growth of slug flow. Moreover, the vibrations of pressure in microchannels will also depress the growth of slug flow.In our research, we observed two kinds of flow patterns, which are inversed vapor flow patterns and partial dry out slug flow patterns. Inversed vapor flow pattern will occur with the vibrations of inlet temperature and inlet pressure. And partial dry out slug flow patterns will decrease the ability of heat transfer.