Experiment Investigation of R134A Flow Boiling Process in Micro-Channel With Cavitation Structure

One cavitation structure that the channel cross section expanded suddenly was introduced in single straight microchannel. The experiment was carried out with R-134a as the fluid medium, which was drove by gear pump. The flow pattern was observed by CCD and microscope. The average boiling heat transfer coefficient was estimated with the calculation method proposed in this paper. The experimental results present the boiling began at the cavitation structure, and stable flow boiling was maintained. When heat power grew up the boiling became strong then the pressure drop in the micro-channel increased and the heat transfer was enhanced. The liquid percentage in two-phase flow increased and the length of boiling area became small when mass flux grew up with the fixed heat power.