矩形微槽内水的流动沸腾换热及可视化实验研究

An experimental study on the flow boiling heat transfer and its visualization of water in a rectangular micro-groove horizontally laid

本实验以水为工质，对截面尺寸为0．4mm×0．4mm水平布置的不锈钢矩形微槽内流动沸腾进行换热特性和可视化研究．质量流速G范围为62．5—187．5kg，（m^2·s），进口温度分别为Tin=30℃、45℃、60℃．实验结果表明：在较低干度下，换热系数随着干度的增加而增加；干度较大时，换热系数保持不变直至换热恶化．质量流速的增加使换热系数有较大增加，进口温度的变化对换热系数几乎没有影响．可视化研究发现低的壁面过热度时，有大量气泡产生；在本实验范围内，微槽内沸腾的流型主要有塞状流和环状流两种．

This paper describes an experimental study on in a steel micro-groove horizontally laid with a rec between 62.5kg/（m^2 · s） and 187.5kg/（ m^2·s） tangular the flow boiling heat transfer and its visualization of water cross section of 0.4 × 0.4mm^2 . The mass flux of G ranges and the inlet temperature Tin, is set at 30℃,45℃ and 60℃, respectively. The resuhs show that, under the condition of low vapor quality, the heat transfer coefficient increases with the increase of vapor quality, and, while it remains at a certain value with no change until the boiling crisis happens under high vapor quality. The augment of the mass flux can increase the heat transfer coefficient markedly, while the change of the inlet temperature almost doesn＇t have any influence on it. As to the visualization study, the emergence of great deal of bubbles is observed when the wall superheat is low. And the main flow patterns found in the experiment are plug flow and annular flow.