Numerical Simulation Coupling on Fluid Flow and Heat Transfer in Nozzle and Equipment Cabin of Solid Rocket Motor during Operation Process

Abstract

Driven by the goal of studying the temperature changes in the nozzle and equipment cabin of solid rocket motor during the whole process of ignition starting, working, cooling and decompression, this paper uses the fluid dynamics software which uses the RNG k-ε turbulence model to simulate the mixing of the fuel and oxidant and the Sutherland law to describe the viscosity of gas and air, and the controlling equation is the two-dimensional axisymmetric viscous compressible URANS equation. In this paper, the temperature field of the nozzle and equipment cabin in the working process of solid rocket motor during 0 ∼ 60s is numerically simulated, and the ground experiment is carried out. The results show that (1) the numerical simulation results are in good agreement with the ground test results, and the absolute value of the maximum error appears at the time of 60s, which is 5.9k. indicating that the numerical calculation method and heat source equivalent method established in this paper are suitable for the temperature field simulation of composite structure nozzle and equipment cabin, (2) the unsmooth surface of the nozzle formed by high temperature ablation makes the flow situation in the divergent section of the nozzle complex and affects the heat transfer coefficient of the wall contacting with the equipment cabin, (3) due to the insulation design of the equipment cabin, only a small part of the heat is transferred to the equipment cabin. During the whole working process of solid rocket motor, the temperature field of equipment cabin increases sharply at both ends and gently in the middle.