Turbopump Booster Turbine Performance: Comparison Between Monophase and Multiphase Flows Using CFD

Boosters are commonly used in liquid propellant rocket engines (LPRE) to allow lower propellant pressures in their storage tanks and, thus, smaller structural masses, contributing to cavitation free operation in the subsequent main turbopumps (TP). Boosters can be identified as key components for the overall performance of large engines, and if their operating requirements are stringent, they can operate under cavitation. Thus, effective design and performance tools are fundamental to design the components of these boosters considering this phenomenon. The simulation techniques based on turbulent and multiphase 3-D Computational Fluid Dynamics (CFD) were used in this work at steady state regime. The simulations were done using the commercial software CFX from ANSYS^® Workbench. The study was conducted analyzing the performance of the first stage of the hydraulic axial turbine of the liquid oxygen (LOX) booster of the Space Shuttle Main Engine (SSME), at various operation points under cavitation, considering 3.0% tip clearance relative to blade height. The results obtained for, the performance parameters of this stage were compared with those obtained through monophase simulation, and the multiphase technique showed results closer to the experimental ones around the design point (DP), with increased simulation times acceptable for the computational resources currently available. Moreover, the results from the current work show the importance of considering the effects of cavitation through multiphase flow in hydraulic turbines.