Criticalities in high pressure cryogenic test facilities

An indigenously developed cryogenic engine using Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) as propellants powers the upper stage of the Indian launch vehicle. The engine works on the gas generator cycle which aid in the modular development of the engine, wherein, individual subsystems were developed and tested independently. The thrust chamber had to be tested in the standalone pressure fed mode, without the turbopumps, to qualify it at nominal and off nominal conditions. In this regard, a unique facility, the Thrust Chamber Test facility, was realized at ISRO Propulsion Complex, Mahendragiri. During the realization and commissioning of the facility and testing of the thrust chamber, certain challenges were encountered. Approaches adopted to overcome the challenges posed by chill down of highpressure cryogenic tanks, chill down of high-pressure cryogenic fluid transfer superinsulated pipelines, rapid pressurisation requirement of the test article and selection of flow components for high pressure applications are detailed in this paper.