Thermal stratification in LH2 tank of cryogenic propulsion stage tested in ISRO facility

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Xavier, M.^1 ; Edwin Raj, R.^2 ; Narayanan, V.^3

Cryogenic Stage Propellant Fluid Systems Division, Liquid Propulsion Systems Centre, ISRO, India^1

Mechanical Engineering Dept., St. Xavier's Catholic College of Engg., India^2

Cryogenic Propulsion Engine and Stages Entity, Liquid Propulsion Systems Centre, ISRO, India^3

关键词: Cryogenic propellant tanks;    Cryogenic propulsion;    Cryogenic propulsion stages;    Free-convection Boundary Layer;    Liquid free surfaces;    Pressure maintenance;    Stratified liquids;    Tank pressurization system;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012063/pdf
DOI  :  10.1088/1757-899X/171/1/012063

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Liquid oxygen and hydrogen are used as oxidizer and fuel respectively in cryogenic propulsion system. These liquids are stored in foam insulated tanks of cryogenic propulsion system and are pressurized using warm pressurant gas supplied for tank pressure maintenance during cryogenic engine operation. Heat leak to cryogenic propellant tank causes buoyancy driven liquid stratification resulting in formation of warm liquid stratum at liquid free surface. This warm stratum is further heated by the admission of warm pressurant gas for tank pressurization during engine operation. Since stratified layer temperature has direct bearing on the cavitation free operation of turbo pumps integrated in cryogenic engine, it is necessary to model the thermal stratification for predicting stratified layer temperature and mass of stratified liquid in tank at the end of engine operation. These inputs are required for estimating the minimum pressure to be maintained by tank pressurization system. This paper describes configuration of cryogenic stage for ground qualification test, stage hot test sequence, a thermal model and its results for a foam insulated LH2 tank subjected to heat leak and pressurization with hydrogen gas at 200 K during liquid outflow at 38 lps for engine operation. The above model considers buoyancy flow in free convection boundary layer caused by heat flux from tank wall and energy transfer from warm pressurant gas etc. to predict temperature of liquid stratum and mass of stratified liquid in tank at the end of engine operation in stage qualification tests carried out in ISRO facility.