The Research Of Gas-particle Two-phase Flow In Nozzle With A Large Load Ratio And The Channel Shape Optimization Design

The two-phase equilibrium flow method can be used for the calculation and correction of the nozzle efficiency, owing to the load ratio of nozzle two-phase flow in traditional solid rocket engine which is lower than 30%. It could be obtained ideal results with the condition regarding of the correction of two-phase in the traditional nozzle design theory. But it is absolutely different for nozzle two-phase flow with large load ratio, which is approximate to isothermal flow as the hypothesis of equilibrium flow does not in agreement with the actual flow. It is significant to study the law of nozzle flow for the nozzle design and the obtaining of maximum propulsive efficiency. The study of nozzle two-phase flow with large load ratio is needed further study.In this paper, nozzle model is established with adaptive unstructured quadrilateral mesh and the finite volume method is used to calculate the differential equations. The approximate Riemann solver of Harten, Lax and Van Leer(HLL) is used calculate the gas contact surface flux, both the HLL Riemann solver and the Steger and Warming flux-vector-splitting technique are used to determined the inviscid flux of the particle phase that the latter method is used here as there is only one eigenvalues in the convective flux。It has been analyzed the results calculated by the above two method. The Fractional-Step-Method is used to solve the governing equations which are divided into a homogeneous and an inhomogeneous part. The 2-order Runge-Kuta method is used to march on the time. Three models are established for inviscid, laminar and turbulent flow, the differences among the three models have been analyzed. It has been obtained the law of two-phase flow with large load ratio under the condition of different load ratios, different particle diameters and different expansion angles. The thrust formula of approximate isothermal two-phase flow theory has been derived preliminarily then three different results have been obtained from approximate isothermal formula, integral calculation formula along the wall of nozzle and isentropic formula respectively.The results calculated from quasi-isothermal calculation formula are more accurate than those from isentropic formula compared to the actual thrust. It could be provided feasible suggestions for the actual design of solid rocket engine with large load ratio according to the optimization expansion angle obtained from the calculation of the ratio of thrust and engine initial quality under different expansion angles.