水工质微波等离子推力器喷管流场及推力性能研究

采用Delaunay方法生成三角形单元的非结构网格离散计算区域,利用格心有限体积法对水工质微波等离子推力器喷管流场和推力性能进行了数值模拟.揭示了水工质微波等离子推力器喷管的流动规律.研究结果表明:在喷管入口压强为0.35 MPa时,增加工质气体的总温,可以提高推力器的比冲,同时推力的变化很小.在收敛角和扩张角不变的情况下减小喷管喉径,能够略微提高推力器的比冲.而推力器腔体内压强变化很大.保持喷管喉径和出口直径不变,在喷管扩张半角从10°增大到40°的过程中,推力器的比冲和推力先增大后减小；扩张半角为17°时,推力器性能最佳.

Research on the Flow Fields and Thrust Performance of Nozzle of Water-fed Microwave Plasma Thruster

The Delaunay method,which was used to generate unstructured grid of triangular mesh for the computational domain, and cell-centred finite volume method were applied to the numerical simulation of the flow fields and thrust performance of nozzle of Water-fed Microwave Plasma Thruster(WMPT). The flow rules of the nozzle of WMPT was revealed. The results show that: when the inlet pressure of the nozzle is 0.35MPa, the specific impulse of the thruster can be improved significantly while little influence is made on the thrust performance by increasing the total temperature of water vapour; At constant convergence and divergence angles, reducing nozzle throat diameter results in slight increase in the specific impulse, but variations of chamber pressure is large; When nozzle throat and outlet diameters are unchanged, both the specific impulse and thrust decrease after the initial increase as the half expansion angle of the nozzle rises from 10 to 40 degrees, with the best performance found at 17 degrees.