Calculation For A Three-dimensional Jets Flowfield Of The Rocket

The jetflow of the rocket, which is a kind of high-temperature, high-velocity and gas-solid phase chemical flow, generates blazing flame and it will harm the operators and weapon system. Then flowing rules of the jetflow must be investigated. The flowing field is very complex , especially the interfering phenomena of multi-jetflows which have more complex structure of shock. Generally, the disturbed flowing field by multi-jetflows has three-dimensional shock shape. The structure and the shock disturbing intensity not only lie on the proportion of pressure at the exit of the nozzle, but also the distance between the nozzles'axis. As a result, the numeral simulation of the disturbed field , which has complex shocking structure, must use the high precise numerical scheme in order to improve the solving power of shock and minish the illusive oscillation. The paper employed a second order Van Leer scheme which has TVD property and used body-fitted coordinates to simulate the above field's characters. The main works are as follows.1. The irregular special grid is transformed to the regular calculative one by using the body-fitted coordinates, thus the grid fits any boundary shapes of flowing fields and improves the calculative precision at boundary values. The paper designs the body-fitted grid by a numerical method, and improves the density of partial areas to heighten the grid generating ability of PHOENICS. The calculating result proves the facility of the body-fitted grid using at the complex special areas.2. The paper has emulated the two and three-dimension constant flowing state of supersonic and under-expanded jetflow as the flow is viscous and compressible. In order to illustrate the developing trend along the axis and the shape of special-complex shock, a corresponding model is also built. The paper has provided the isoline at critical location, and the simulation of representative phenomena is the main content. At the same time, here also analyzed the creating reason, flowing rules and influencing factors of special shock. At the endof this part, the paper compared the flowing structure between the multi-nozzle and the simplex nozzle.3. After introducing the actual estate when the multi-nozzle jets, the paper constitutes the status function, difference function and values correlative boundary condition. Using these conditions the non-constant multi-nozzle jetflow field is emulated. The paper captures the complex moving chock system and describes the special shock's occurring and developing course by describing the parameters' changing figure at ten key time. Some other contents has also researched in the paper, that is the mutual effecting process between the shock and the vortex.