A fast algorithm to solve viscous two-phase flow in an axisymmetric rocket nozzle

Abstract

SUMMARY A numerically fast algorithm has been developed to solve the viscous two-phase flow in an axisymmetric rocket nozzle. A Eulerian‐Eulerian approach is employed in the computation to couple the gas‐particle flow. Turbulence closure is achieved using a Baldwin‐Lomax model. The numerical procedure employs a multistage time-stepping Runge‐Kutta scheme in conjunction with a finite volume method and is made computationally fast for the axisymmetric nozzle. The present numerical scheme is applied to compute the flow field inside JPL and AGARD nozzles. # 1998 John Wiley & Sons, Ltd. Nozzle flow field analysis constitutes an important area of research and development work in aerospace engineering, since the performance of a launch vehicle depends on the propulsive power of the nozzle. Optimum thermal insulation of the nozzle wall also demands accurate estimation of the heat transfer rate to the nozzle wall. The aluminium oxide particles in the exhaust contribute to an inefficiency in the expansion process in the propulsive nozzle. This inefficiency is attributed to velocity and thermal lag between the gas and particles. It is necessary to know the behaviour of the two-phase flow expanding through the nozzle in order to evaluate the motor performance. Since the 1970s, numerical simulation of the gas‐particle two-phase nozzle has been extensively studied with the development of numerical schemes. Chang 1 has solved the unsteady two-fluid equations in conservation form using MacCormack’s scheme to predict the gas and particle fields in an axisymmetric convergent‐divergent nozzle. Crowe 2 provides a review of numerical models for dilute gas‐particle flows. The main advantage of the two fluid model is that the numerical procedures already established for single-phase flow can be used for two-phase flow. However, the major drawbacks of this scheme are numerical diffusion of the particle phase and higher computer storage and computer time requirements for multisize particles. A numerical study of the gas‐particle flow in a solid motor nozzle has been made by Hwang and Chang 3 using MacCormack’s explicit scheme in