Thermoelasticity Coupling Transient Response of Composite-Material Direction Pipe

Based on the positive scheme method, the thermal load of the jet flow in an inner composite-material direction pipe is obtained, and the thermoelasticity coupling transient response is investigated. The positive scheme method with second-order accuracy is extended for solving the axisymmetric Euler equations, and the supersonic axisymmetric jet flow over a missile afterbody containing jet exhaust is simulated. The correctness of the development for the positive scheme method is verified. With the developed positive scheme method used to simulate the jet flow in the inner direction pipe, the thermal load is obtained. The thermoelasticity coupling finite element model of the composite-material direction pipe is established, and the stress response under dynamic pressure, unsteady temperature, and coupling state is obtained. Results show that, at the beginning of engine ignition, the effect of dynamic pressure and temperature field on the coupling stress is basically the same, and after that, the contribution of the temperature field to the coupling stress increases, and the thermal stress is the main factor affecting the strength of the composite-material direction pipe.

The Research on the Axis-Symmetric Development and Verification for the Positive Scheme Numerical Method

The mathematic express of positive scheme axis-symmetric Euler equations is derived. With the numerical calculation of oblique shocks regular reflection problem, the validity of the positive scheme method and the self-programmed codes is verified. The positive scheme method is developed to solve the axis-symmetric Euler equations and then used to simulate the supersonic axis-symmetric flow over missile afterbody. The results show that: the numerical simulation match well with the experimental results and the numerical results obtained by the already existing high accuracy scheme method, the correctness of the development of positive scheme method is verified.