Conceptual Study on Flight Demonstration of Mixture-Ratio-Controlled Throttling of Hybrid Rocket
- Paper number
IAC-16,C4,6,1,x33272
- Author
Dr. Toru Shimada, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency, Japan
- Coauthor
Mr. Tomoaki Usuki, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency, Japan
- Year
2016
- Abstract
\begin{document} %Report \normalsize Results of conceptual study on technology demonstration in flight of a newly proposed hybrid rocket (HR) being enabled mixture-ratio-controlled throttling (MRCT) are described in this paper. The proposed system, named Altering-intensity Swirling-Oxidizer-Flow-Type (A-SOFT) hybrid rocket\textsuperscript{[1]}, is essentially-non-explosive and equipped with an MRCT technology. By performing a multi-objective optimization of A-SOFT HR, it has been shown that MRCT is remarkably effective for expanding mission applicability of a sounding rocket\textsuperscript{[2]}. The A-SOFT is realized by independently modulating axial and tangential oxidizer mass flow rates so that both thrust and mixture ratio (O/F) are simultaneously controlled. In most cases, during throttling of a hybrid rocket, O/F varies in accordance with the $(1-n)$-th power of the oxidizer mass flow rate, where $n$ is usually in the range of $0.5$-$0.8$. So, the propulsion performance deteriorates remarkably in throttling down at lower-than-optimum O/F, or in throttling up at larger-than-optimum O/F, since the specific impulse is usually an upward-convex function of O/F\textsuperscript{[3]}. From launch-system-wise viewpoints, one of the most serious problems caused by O/F shift is the resulting propellant residue\textsuperscript{[4]}. So, MRCT is one of the most-important key technologies for the achievement of high-energy mission, such as a satellite launch, of hybrid rockets in space transportation. Mission requirements for the technology demonstration of MRCT of a hybrid rocket in flight, are to demonstrate 1) capability of designing a compact thrust chamber employing a method of high fuel regression rate, 2) capability of lowering propellant residual and of wide-range thrust control with MRCT technology, and 3) capability of re-ignition in space. During the flight demonstration, for a feedback control of both two quantities being assured, real-time on-board measurements of the fuel web-thickness and of the combustion pressure have to be done. \small \textbf{References} [1] Shimada, T., et al., paper 2980899, Space Propulsion, 3AF, Cologne, 2014 [2] Usuki, T. and Shimada, T., IAC-15-C4.2.3, International Astronautical Congress, Jerusalem, 2015 [3] Karabeyoglu, A., et al., AIAA 2014-3851, Propulsion and Energy Forum, Cleveland, July 2014 [4] Ozawa, K. and Shimada, T., AIAA 2015-3832, Propulsion and Energy Forum, Orlando, July 2015 \end{document}- Abstract document
- Manuscript document
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