【摘要】 在考虑表面张力动量源项和气—液两相间传热传质源项的条件下,基于Volumeof Fluid算法,建立了板式蒸发式冷凝器气—液两相降膜流动传热传质的计算模型.利用该模型定量分析了壁面热流密度、液相进口温度和空气流速对竖直板面温度分布、气—液两相界面处潜热和显热传热热量密度的相对关系的影响.结果表明:液膜和空气内温度随壁面热流密度的增大而增大,在气—液两相界面处,温度梯度不连续;气—液两相界面处的传热形式以水蒸发传质引起的潜热传热为主、空气显热传热为辅,且传热热阻主要集中于水膜内;随空气流速的增加,气—液两相间传质量也随之增大.更多还原

【Abstract】 By considering the momentum source term of surface tension as well as the source term of heat and mass transfer in gas-liquid two-phase flow,a computational model based on the Volume of Fluid(VOF) algorithm was established to describe the heat and mass transfer of two-phase falling film in a plate-type evaporative condenser.Then,the model was used to quantitatively analyze the influences of wall heat flux,inlet liquid temperature and air velocity on the temperature distribution and on the relative relationship between the latent heat transfer density and the sensible one at the gas-liquid interface.The results indicate that the temperatures of liquid membrane and air both increase with the wall heat flux,that the temperature gradient is discontinuous at the gas-liquid interface,that the heat transfer at the gas-liquid interface is mainly the latent heat transfer caused by water evaporation and is assisted by the sensible heat transfer caused by the air,that the heat transfer resistance is mainly due to the water membrane,and that the mass transfer improves with the air velocity.更多还原