Flow Field Investigation in a Partial Admission Supersonic Turbine of LOX Booster Turbopump for Staged Combustion Cycle Based Rocket Engine

Abstract

To obtain high specific work output with small mass flow rate, high-pressure ratios across the turbines are required in liquid rocket engine turbopumps. An impulse-type supersonic turbine can achieve this. To prevent losses due to low blade aspect ratio and issues related to manufacturing and industrial problems, partial admission configuration is adopted. Partial entry in a turbine is achieved by adjusting the extent of the nozzle arc of admission, leading to a strong unsteady circumferential asymmetry of flow parameters in the rotor passage, and degradation in efficiency. The pressing need of aerodynamic design of supersonic partial admission turbines to improve their efficiency demands an investigation of the viscous fluid dynamic of the turbine flow field. This work reports the aerothermodynamic steady state CFD analysis to obtain the performance parameters of a three-dimensional partial admission turbine for LOX booster turbopump in a semicryogenic engine using ANSYS® CFX. The areas of steady loss have been identified through entropy generation contours, and the effects associated with aerodynamic loss structures like secondary flow, shock location, recirculation with additional pumping and mixing losses have been investigated for designed operating condition corresponding to 100% nominal thrust.

Finding an optimal blade-profile to improving the performance of partially admitted turbines

“…Martins et al (2016) analyzed the application of a single-stage partial-admission turbine in an organic ranking cycle and presented a design optimization procedure that was aiming the best possible performance. A full stage three-dimensional steady analysis of partial admission turbine of LOX booster turbo pump was performed by Mishra and Ghosh (2017). In this work, the overall performance of partial admission axial turbine for different throttling conditions was analyzed, and the location of zones that were responsible for the degradation of efficiency was identified.…”