An experimental investigation of heat transfer in flow boiling in minichannels

In this thesis, flow boiling heat transfer in minichannels is investigated experimentally. In the study, five single-channel heat sinks having the same hydraulic diameter but different width and depth values are tested. In order to understand boiling mechanism in detail, flow visualization tests are conducted as well as the temperature and pressure measurements. The effects of different values of the mass flux, vapor quality, heat flux and width to depth (aspect ratio) on heat transfer coefficient and pressure drop are obtained. For a broad range of working parameters optimum value of aspect ratio is determined. It is disclosed that nucleate boiling is the dominant heat transfer mechanism while the dominant flow patterns are bubbly and slug flow.