摘要
To investigate the characteristics of the condensation in gasoline vapor condensation recovery,the condensation process of gasoline vapor with turbulent flow in a vertical tube is simulated based on the gas-liquid two-phase flow model.An effective diffusion coefficient is used to describe mass diffusion among the species of gasoline vapor.Several variables including temperature,pressure,liquid film thickness and the variation of the Nusselt number in the tube are simulated.The effects of the inlet-to-wall temperature difference and the Reynolds number on the condensation rate and the Nusselt number are obtained by modelling.The results show that heat transfer and condensation can be enhanced significantly by increasing the inlet Reynolds number.However,the increase in the inlet-to-wall temperature difference has little effect on the condensation rate.It is also found that the gasoline vapor condensation rate is influenced greatly by the mass transfer resistance.The comparison of results from the model with previous experiments shows a good agreement.
为了探索油气在冷凝回收过程中的冷凝规律,采用气液两相流模型描述了油气在竖直管内湍流流动时的冷凝过程.采用有效传质系数描述了油气组分的质量传递.模拟了油气在管内冷凝时的温度、管内压力、液膜厚度和Nusselt数的变化,得到了入口油气和管壁的温差、雷诺数对冷凝率和Nusselt数的影响.结果显示:增大入口雷诺数能显著增强传热和冷凝,但是增大入口油气和管壁的温差对冷凝率的影响较小;另外,还发现传质阻力对油气冷凝率有较大影响.此模型的计算结果与先前的实验数据能够很好地符合.
