Abstract The temperature and height of waterfilm were a pair of coupled characteristic parameters indicating the instant heat/mass transfer during static film flash of pure water. Their evolutions and interactions were studied through experiments with initial height of waterfilm ranging between 0.15 and 0.3 m, initial temperature between 80.2 and 93.0 °C, initial pressure of vacuum chamber between 0.013 and 0.061 MPa. Results suggested both height and decrease rate of temperature of waterfilm experienced a rapid increase to peak value and a gradual decline after that. Considering most of heat transfer happened within waterfilm, volumetric evaporation coefficient was introduced as the total heat flux transferred through all bubble interfaces within unit volume of waterfilm under unit superheat. This coefficient increased significantly with rising volumetric void fraction of waterfilm. Except vapor generation, mass transfer during static flash also included the overflowing of vapor. Its overflowing speed increased with initial height of waterfilm. According to these results, a model was set up to calculate the evolutions of temperature and height of waterfilm from given evolution of saturation temperature corresponding to the pressure of flash chamber.

中文翻译：

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静态闪光过程中水膜温度和高度演变的实验研究

摘要 水膜温度和水膜高度是反映纯水静态膜闪蒸过程中瞬时传热传质的一对耦合特征参数。通过实验研究了它们的演变和相互作用，水膜初始高度在 0.15 到 0.3 m 之间，初始温度在 80.2 到 93.0 °C 之间，真空室初始压力在 0.013 到 0.061 MPa 之间。结果表明，水膜温度的高度和下降率均经历了快速上升至峰值后逐渐下降的趋势。考虑到大部分传热发生在水膜内，引入体积蒸发系数作为单位过热度下单位体积水膜内所有气泡界面传递的总热通量。该系数随着水膜体积空隙率的增加而显着增加。除了蒸汽的产生，静态闪蒸过程中的传质还包括蒸汽的溢出。其溢流速度随着水膜初始高度的增加而增加。根据这些结果，建立了一个模型来计算对应于闪蒸室压力的饱和温度的给定演变的温度和水膜高度的演变。