Experimental and theoretical Analysis for propellant tank Pressurisation system of a cryogenic Propulsion stage

Abstract

Space exploration initiatives demand advances in propulsion technology to accomplish complex missions. Realising the significant performance improvement and advantages of using cryogenic propulsion systems in satellite launch vehicle, India, Japan, China, Russia, USA, etc., developed their own cryogenic propulsion stages using LOX and LH2 as oxidiser and fuel respectively. Cryogenic stage designated as C25 is developed by Liquid Propulsion Systems Centre of Indian Space Research Organisation (ISRO) for the upper stage propulsion of GSLV MkIII launch vehicle. This stage is designed to stor 23,300 kg of LOX and 4,990 kg of LH2 in foam insulated propellant tanks. A pump fed cryogenic engine operating on gas generator cycle is designed and developed for C25 stage which delivers a nominal thrust of 200 kN in vacuum. Propellant tanks are connected through inter-tank structure (ITSc) and independent umbilical connector units are provided in ITSc region for propellant servicing operations. Liquid oxygen tank is provided with a pressurisation system for constant pressure maintenance at 2.2 bar during LOX outflow of 30 litre per second (lps) from tank. Helium gas is used as pressurant gas for LOX tank pressurisation system and is stored in two high pressure gas bottles mounted inside LH2 tank. A pressure regulator module mounted on LOX tank regulates the helium gas from the storage pressure of 225 bar to 2.2 bar for meeting the tank pressure requirement during engine operation. A heat exchanger is provided in LOX tank pressurisation system to heat up the helium gas from 20 K to 130 K using the heat source of LOX turbine exhaust gas. LOX tank is also provided with vent and relief system for over-pressure protection. Feed system supplies LOX to the pump mounted in engine system. Similar systems are provided in LH2 tank of C25 Stage. newline