ISSN Online: 2688-7231
ISBN Online: 978-1-56700-478-6
Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)
THERMODYNAMIC ANALYSIS OF LOX/METHANE EXPANDER CYCLES
Abstract
The objective of this study was to provide preliminary
cycle designs for cryogenic rocket engines which power upper
stages of a launch vehicle. The work describes the development
of a computer model to perform thermodynamic analysis of
LOX/Methane expander cycles for a liquid rocket engine pumpfed
propellant feed system. LOX/Methane as a propellant has
advantages of providing higher specific impulse and low soot
combustion compared to RP-1. In contrast to LH2, it provides
superior storability, higher fuel density, boiling temperatures
and vapour pressure.
The outlet temperature obtained from the regenerative cooling portion of the nozzle is about 383 K for the chamber pressure of 6 MPa. The temperature is found to sustain the entire power cycle for the given thrust value of 100 kN. The completed cycle analysis program was validated against the literature data available on closed expander cycle developed for liquid rocket engines RL10 burning propellant combination LOX/LH2. In the analysis, the open cycle was found to operate with the minimum turbine power of 0.384 MW for the mission desired thrust of 100 kN and operating at a combustion chamber pressure of 6 MPa. The present work relates to the detailed comparison of the performances for several other variations of expander cycles namely closed dual expander cycle, closed split expander cycle, closed dual-split expander cycle, open expander cycle and gas generator augmented expander cycles to identify the optimum variant. The open expander cycle consumed the least power for all the operating conditions whereas the split expander cycle is found to consume lower power in the closed expander cycles operating at chamber pressures below 3.5 MPa.
The outlet temperature obtained from the regenerative cooling portion of the nozzle is about 383 K for the chamber pressure of 6 MPa. The temperature is found to sustain the entire power cycle for the given thrust value of 100 kN. The completed cycle analysis program was validated against the literature data available on closed expander cycle developed for liquid rocket engines RL10 burning propellant combination LOX/LH2. In the analysis, the open cycle was found to operate with the minimum turbine power of 0.384 MW for the mission desired thrust of 100 kN and operating at a combustion chamber pressure of 6 MPa. The present work relates to the detailed comparison of the performances for several other variations of expander cycles namely closed dual expander cycle, closed split expander cycle, closed dual-split expander cycle, open expander cycle and gas generator augmented expander cycles to identify the optimum variant. The open expander cycle consumed the least power for all the operating conditions whereas the split expander cycle is found to consume lower power in the closed expander cycles operating at chamber pressures below 3.5 MPa.