ЕКСПЕРИМЕНТАЛЬНЕ ДОСЛІДЖЕННЯ ПАРАМЕТРІВ НАДХОЛОНОЇ СИСТЕМИ НАДДУВАННЯ БАКА ПАЛЬНОГО РУШІЙНОЇ УСТАНОВКИ

Abstract

The study is focused on modern rocket engine fuel tank pressurization systems. These systems use the after burn oxidative generator gas principle. The rocket engine can throttle. The pressurization system type was changed during ‘Zenith’ and ‘Energy’ design based on meticulous mathematical modeling results. The transition from the traditional hot helium pressurization system to a newer one was performed. The new methodology got a ‘super-cold’ naming. The feature is helium input with cryogenic-temperature (90-50K) into fuel tanks. All the source data is available at the design stage for super-cold pressurization systems, unlike hot/traditional ones. The new system turns out to be 30% lighter. The super-cold system parameters improvement via experimental data analysis is set as a goal of this study. The experimental results are compared with mathematically modeled. The tank gas pressure sufficient convergence is shown. Some gas temperature differences are explained by gas temperature layering. The in-flight temperature decrease over fuel temperature did not exceed 70K. The temperature difference was decreasing as engine work was finishing. The input fuel temperature drop on the pump was not detected. The fuel upper bottom local temperature drop did not exceed 7 degrees based on two measurements. The difference between modeled and actual cylinder output helium temperature (up to 20K by the end of engine operation) was shown. The hypothesis explaining the fact is established. The modeling methodology assumes the equivalent tank diameter to be one equal to its volume. This leads to reducing the calculated (actual) heat exchange surface. The analyzed experimental data powers further super-cold pressurization system design improvement.