Numerical Investigation of Water Injection Effects on Jet Centerline Temperature and Ignition Overpressure by Using OpenFOAM

In order to have a safe and successful launch, analyzing the launch environment is necessary. During launch, two kinds of pressure waves appear: (1) ignition overpressure (IOP) waves and (2) acoustic waves. IOP waves have higher amplitude and lower frequency. However, acoustic waves have lower magnitude and higher frequencies. These waves can have destructive effects on the launch vehicle and launch structures. By using water injection on the rocket nozzle’s hot exhaust plumes, the effects of these waves can be mitigated, and launch pad surface cooling can also be achieved. This paper aims to investigate the effect of water injection on IOP and temperature reductions. Computational fluid dynamics (CFD) analyses are conducted using OpenFOAM software. In order to simulate the Water injection, a multiphase solver based on the Lagrangian method is implemented. An OpenFOAM external library, reactingLagrangianPimpleCentralFoam (RLPCF) is selected for this purpose. The Large Eddy Simulation (LES) is used for flow field analysis. The results show that water injection effectively reduces the jet centerline temperature.