Numerical Method to Simulate the Performance of Microgravity Membrane Gas-Liquid Separator

Microgravity membrane gas-liquid separation technology is one of the key technologies of environmental control and life-support system, and the effective simulation of gas-liquid two-phase flow is an important method to carry out the research on the miniaturization and lightweight of the technology or the separator. However, due to the lack of experimental data and theoretical understanding, it is difficult to give the inlet boundary in the real gas-liquid two-phase flow under the real microgravity condition. How to obtain the gas-liquid interfaces with different geometrical scales from the average two-phase flow parameter is a special multi-scale problem of gas-liquid interface. Moreover, the film thickness with μm order makes it difficult to establish the real geometric model in the simulation, which belongs to a geometric multi-scale problem. An Eulerian two-fluid model with an interface probability approximation method (TFM-IPAM) is proposed to solve the multi-scale problem of the gas-liquid interface, providing a reasonable inlet flow pattern for the simulation. And the momentum source method is proposed to simulate the selection and permeability characteristics of the membrane, avoiding the geometric multi-scale problem. Further, a 2D straight pipe simulation is carried out, and the effectiveness of the method is verified by the flow patterns form the simulation and the references. The results show that the TFM-IPAM can capture and filter the interface with different scales, which can enhance the adaptability of the calculation method and the computability of the problem. The momentum source method can realize membrane selectivity and permeability, and more realistic permeability process can be carried out. The TFM-IPAM combined with the momentum source method is a simple and effective calculation method for this kind of simulation technology problems and engineering applications. The CFD simulation tool developed will be powerful to rapidly analyze or design the microgravity membrane gas-liquid separator.