Research of heat transfer processes during pre-launch chilldown of PS consumption lines of upper-stage LV

The paper deals with heat transfer processes during pre-launch chilldown of consumption lines of the upper stage propulsion systems (PS) by a cryogenic component. Propulsion systems operating on high-efficiency cryogenic propellant components may be used at the first as well as at the upper stages of launch vehicles to deliver spacecrafts into final orbits. Cryogenic PS produce high specific impulse being environmentally friendly, which may provide a growing interest towards their application. Low temperature of cryogenic propellant components may pose considerable challenges when chilling down, fueling and storing components as well as draining fuel tanks and starting PS, especially under zero gravity conditions in long-term space flights. Complex experimental facilities (EF) along with test methods as well as physical and mathematical models for calculating nonsteady multiple-phase heat transfer processes with intense phase transformations are being developed to overcome these challenges. The methods for mathematical modelling of the chilldown and cryogenic component flow processes have been proposed considering mass - and energy-conservation equations in relation to supply lines, tank gas blanket and tank volume filled with cryogen liquid. Closing dependency ratios have been specified according to results of bench and flight testing of PS to solve equations for heat transfer and friction in the cryogenic supply system components of test stand (TS) and PS.Also, the paper studies heat transfer processes during pre-launch chilldown of consumption lines (CL) of 12KRB LV PS with the lox/liquid hydrogen engine KVD-1 considering results of bench and flight testing of the block.Findings on chilldown and fueling of the 12KRB upper stage may be used to verify calculation models while designing and developing the KVTK advanced upper stage with the lox/liquid hydrogen engine RD0146 of the Angara-A5V heavy class launch vehicle.