Numerical Analysis on Effect of Structural Parameters on Flow Field and Internal Trajectory in Gas-Steam Ejection Systems

This paper aims to study the influence of the structure of spray holes and throats on the flow field and the internal trajectory of the gas-steam ejection device. The compressible Navier-Stokes equations, discrete ordinate methods and RNG k-epsilon turbulence model are utilized to simulate the two-phase flow of the rocket gas with multispecies and the water sprays. The comparison between numerical results and experimental data confirms the accuracy and effectiveness of this model. The simulation analysis on the cases of the ejection process with multiple spray hole diameters, number of spray holes, total spray area, and throat diameter are conducted. The shock wave structure inside the gas-steam ejection device is examined. The simulation results show that, instead of the spray hole diameter and number, the total spray area and secondary nozzle throat diameter are the key factors that affect the flow field and internal trajectory of the gas-steam ejection device. Under the existing spray structure, the maximum number of spray holes is 300 to achieve the stability of the flow field and internal ballistic trajectory of gas-steam ejection devices. By comparing the throat diameters of multiple secondary nozzles, it was found that the minimum throat diameter of the secondary nozzles should be no less than 100 mm. The results could be valuable for the design of gas-steam ejection devices.