Analysis of the Flow Field Characteristics in Conical Nozzles Based on Computational Dynamic Mesh Partitioning Technique

The conical nozzle serves as the energy conversion device in the thrust vector control system of a solid rocket engine. The turbulent flow of high-temperature and high-speed gas inside the nozzle poses challenges for analytical computation of its flow field characteristics, which cannot be accurately measured through experimental means. To address this, a simulated hot firing test of the nozzle was conducted, where the entrance pressure and temperature were set as boundary conditions. Utilizing the computational dynamic mesh partitioning technique and the computational fluid dynamics (CFD) finite volume method, a three-dimensional numerical model of the nozzle's flow field during oscillation was established. The RNG k-ε turbulent model with two equations was employed to compute and analyze the distribution of wall pressure, velocity, Mach number, and temperature under different oscillation angles and entrance pressure conditions. The influence of positive shock waves on the nozzle, particularly in the over-expanded operating state, was also investigated. These analyses aimed to validate the rationality of the nozzle's internal surface design and provide essential data for the structural design of the thrust vector control system.