Numerical Simulation Research For High Altitude Reverse Jet Flow

A variety of flow phenomena, such as rarefied gas flow, reverse jet flow and gas solid two phase flow etc., coexist during the detachment of solid tactical missile between warhead and body at high altitudes. Several relevant work has been done on the problem of reverse jet flow in this thesis.Firstly, in order to examine the rarefied gas dynamic properties of missile without jet flow interaction, based on the theory of free molecular flow, a computational model is established for the computation of aerodynamic force of complicated configuration aircraft which flight in the free molecular flow region. For the reentry warhead with triangular control rudder, wall grid is generated with triangular surface element, and the rarefied gas dynamic properties are analyzed.Secondly, for the purpose of grid generation of complicated boundary flow field, the parabolic-elliptic differential equation method of grid generation is programmed. Using the program to generate 3-D multi-block abutting structured grid of reverse jet flow field with the controlling of concentration and orthogonalization.Thirdly, cell-centered finite volume scheme is presented for solving the 3-D time-dependent N-S conservation equation. A software which can solve jet flow, flow over body and flow in duct or nozzle is established. The problem of reverse jet flow is simulated with the software. The impact of altitudes and detachment distance on the structure of flow field and the aerodynamic properties is examined.Lastly, using DSMC to simulate the movement of solid particle, by combining CFD and DSMC, a CFD/DSMC computational model is developed, and applying the model to solve the problem of gas solid two phase flow in injection duct of nozzle.