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Description
Unlike a turbo pump cycle, an electric pump-fed cycle, which is one of the propellant supply systems for liquid rocket engine, uses an electric motor to drive a pump. unlike a turbo pump cycle. It is relatively simple in configuration compared to a turbo pump cycle, and is conducive to thrust control technology because a propellant flow rate can be adjusted by controlling a pump rotation speed. Electric pump-fed cycle studies have been mainly conducted in the United States and the United Kingdom since the early 2000s, and related research have recently been conducted in Korea as well[1]. Rocket Lab succeeded in commercializing the Electron launch vehicle by successfully launching 32 out of 35 launches of the Electron launch vehicle, a small launch vehicle using the Rutherford Engine, an electric pump-fed cycle engine[2]. In this study, a static characteristic was identified to predict a preliminary performance of an electric pump-fed cycle for a methane 30 kN-class upper stage engine. To this purpose, 1-D simulation analysis of an upper stage engine for an electric pump-fed cycle was carried out using an AMESim program. To conduct with AMESim 1-D simulation analysis, preliminary design of electric pump-fed cycle for an upper stage, such as pipe line, combustor, and nozzle, was carried out. For a preliminary design, NASA CEA code was utilized to select a point where the specific impulse is maximized for LOx/LCH4. Accordingly, basic parameters required for preliminary design, such as specific heat ratio and combustion chamber temperature were derived. In the case of a flow velocity of propellants, the range of 0.9 to 4.5 m/s[3] is empirically recommended to prevent cavitation and 2 m/s was selected. Based on these results, pipe line, combustor, and nozzle were designed. The power system consists of a Li-Ion battery and a BLDC(BrushLess Direct Corrent) motor, and a feed system and combustion unit consist of a pump, regenerative cooling channel, combustor, and nozzle. 1-D simulation analysis, results in 28.68 kN of thrust, showing a difference of 4.4% compared to a target thrust, Rotation speed of a motor was required 9,394 and 9,550 rpm for fuel and oxidant, respectively. Also, battery powers required were 21.15 and 33.42 kW, respectively. We may predict performance in advance based on modeling when components are changed in the future.
References
[1] Ki, W., Lee, J., Lee, H., Roh, T. S. and Huh, H., “Overseas Research Trends of an Electric-Pump Cycle for Application in Upper-Stage Propulsion Systems”, Korean Society of Propulsion Engineers, Vol. 24, No. 1, pp. 64-77, 2020.
[2] “Rocket Lab Electron Launch”, retrieved 11 May. 2023 from https://www.rocketlabusa.com/launch/electron/.
[3] Kim, G. Y., Lee, H. K., and Huh, H., “Components Design of an Experimental System for a Lab-Scaled Electric Pump-fed Cycle”, Asia-Pacific International Symposium on Aerospace Technology, 2021.
| Keywords | Electric Pump-Fed Cycle, Liquid Rocket Engine, 1-D Simulation Analysis, Upper Stage Engine |
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