Effect of leading edge sweep on the performance of cavitating inducer of LOX booster turbopump used in semicryogenic engine

Abstract

Abstract. As a part of the developmental effort towards the realization of a staged combustion cycle based liquid rocket engine, a program on simulation of the LOX booster pump for performance characterization has been taken up. Earlier reported work shows that the pump inducer works satisfactorily under cavitating conditions for the throttling range varying from 90% to 113%. However stall occurs below 90% of the designed flow rate which is to be strongly associated with the inlet backflow vortices due to flow separation [1]. It is envisaged that leading edge sweep may help in to controls the incipience and growth of the backflow vortices at the inlet leading edge tip of axial flow inducer leading to a wider operating range. In this paper, steady state 3D CFD analysis of rotating inducer is performed to examine the effect of leading edge sweep on the performance of axial flow LOX pump inducer using ANSYS ® CFX and has been compared with the performance of the inducer reported by Mishra and Ghosh [1]. IntroductionThe primary constraint on space enterprises is the high cost of escaping Earth's gravity. Therefore, for manned space mission and deep space probes, reusable launch vehicles are contemplated to be used. One of the technological options towards this endeavour is a semicryogenic engine based on high pressure, oxygen rich, staged combustion cycle with LOX and hydrocarbon fuel [2].For high thrust, a mission with high specific impulse, a turbopump propellant feed system offers overall weight reduction, high power to weight ratio with increased payload capacity. This turbopump feed system has at least on booster pump to ensure cavitation free operation at the main pump inlet. Cavitation is the vaporization of the liquid in regions of low pressure, and it has negative consequences lead to substantial losses finally contributing to the degradation of pump performance and higher cost of the mission. This makes cavitation an important issue in design and operation of the booster turbopump.The LOX booster turbopump is typically designed to operate in slightly cavitating condition and permits the main pump to work at higher speeds [3,4]. The term cavitating refers to the fact that the pump is capable of operating over a broad range of incipient cavitation before a noticeable pump head drop off.

CFD Evaluation of a New Centrifugal Pump Concept for Rocket Propulsion

“…The most common issue when using semicryogenic or cryogenic propellants is that the process of their pressurization can lead to cavitation conditions exposure [9]. There are many papers concerning the cavitation phenomenon, which analyze it and try to predict the characteristics of the flow, as well as to give relevant solutions to prevent it [10][11][12]. Cavitation represents the main cause of instability in pumps according to [13].…”