Study on the heat transfer characteristics of regenerative cooling for LOX/LCH4 variable thrust rocket engine

Abstract

It is a challenging task to investigate the regenerative cooling of the variable thrust LOX/LCH4 expander cycle rocket engine. The decreasing methane mass flow rate leads to the two-phase instability in the regenerative cooling channels (RCC) for low engine thrust. In this study, the geometric dimension of RCC with phase-change is developed. Heat transfer cases are studied based on the experimental correlation, which are investigated the heat transfer characteristics of subcritical methane in the RCC. Furthermore, the effect of variable engine thrust on RCC's heat transfer characteristics is analyzed particularly for low engine thrust. The results demonstrate that the gas-side wall temperature (Twg) was stratified due to the different phase-change heat transfer mechanisms. Twg appeared as a local peak value at the throat, which reached a maximum value in the two-phase region. The maximum value of Twg increased from 858.5 K to 863 K with the decrease of the engine thrust in 20–60% RPL. The RCC's temperature rise of 20% RPL was 1.25 times that of 60% RPL (231 K), whereas the pressure drop was 0.72 that of 60% RPL (0.73 MPa). Moreover, the case calculation results could benefit the scheme design and heat transfer analysis of the RCC.