Study on methods for plug nozzle design in two-phase flow

The previous design methods are not proper to design plug nozzle contours of solid rocket motor using the compound propellant, for the existence of metallized particle phase. The flow characters of plug are changed in the two-phase flow condition, therefore the particle-phase influence must be considered in the design. The ideal plug contour is determined by the expansion waves at the design altitude, therefore it is a key to understand the gas-particle interactions in the expansion fan of plug. The method of characteristic (MOC) was applied to study the two-phase flow field of plug, in which the two-phase flow model was Lagrange model. Based on the computational results of MOC, the Angelino method and curve method were improved and extended to be able to design the plug's contour in two-phase flow conditions. Finally the performances of the plugs created by the two improved methods were further examined by CFD, which can consider viscosity and turbulent with respect to the MOC. The examined cases indicate that the plug created by the improved methods can be shortened in length while their thrust performances increase at all altitudes, comparing to the one created by the unimproved methods in the same two-phase flow parameters.