Study of Cavitation/Vaporization in Liquid Rocket Thruster Injectors.

摘要

Gas-particle flows are modeled to attempt to account for coalescence and breakup of liquid droplets dispersed within the gas phase. The one-way coupled population balance equation describing the change of number concentration by the modeled particle to particle interactions and aerodynamic forces is solved by the direct quadrature method of moments (DQMOM). Computations are performed and validated ona typical converging-diverging nozzle attached to a rocket motor. The mass mean diameter evolution is predicted according to different droplet characteristics and pressure in chamber. The required parameters to describe the collision and breakup processes are modeled in laminar and turbulent flow. The modeling was compared to experiments and correlation with respects to the variations in chamber pressure, particle concentration in chamber, and nozzle scale. The comparisons show that the predicted mass mean diameters are in a good agreement with experiments and correlation over 500 psi chamber pressure. The predicted mass mean diameters are also in a good agreement with correlation over 0.2 mole/100 g particle concentration and within all tested nozzle scales. These results indicate the validity of the current model for particle growth/reduction. Coalescence is shown to occur in the convergent section leading to the throat, while breakup processes tend to become important in the throat region and exit cone. In addition, the modeling shows that more growth occurs in boundary layers than mean flow regions.