Study On Water Producing Mechanism Of Vapor Compression Distillation Unit

Vapor compression distillation unit(VCD)is an important equipment for the International Space Station to recycle water from urine.Meanwhile,VCD is the main research direction of the future space station development in China.Under the condition of microgravity,the operation of the device is a complex heat and mass transfer system,which is coupled with many factors.At present,the research on VCD hasn't made substantial progress in China.Therefore,strengthening the research on the mechanism of VCD is of great significance for the development and application of urine recovery system in the future space station.The vapor-liquid separation performance and influencing factors are qualitatively judged by analyzing the radial and axial motion characteristics of the bubble in VCD.The vapor-liquid volume distribution and heat transfer and flow characteristics of phase change process in the evaporator and condenser are numerically simulated by establishing a computational control model of VCD and embedding the latent heat into the energy equation,which is based on the development of the user-defined function.The simulation results are compared with the literature data to judge the reliability of the numerical simulation.The law of liquid film formation and the distribution of temperature field in evaporator are investigated under different inlet flow.Whether the liquid film with different thickness can reach the boiling point is analyzed to achieve evaporation.Under different working conditions,the variation law of VCD's water yield and water production rate is explored.Meanwhile,under the condition that the water yield and water production rate meet the requirements,the optimal parameter value is selected to promote the water production.The research on the factors affecting the water yield and water production rate of VCD provides a data base for further research on urine separation and treatment in China's space station.