JAXA Special Publication JAXA-SP-19-003E

Study on Future Space Transportation System using Air-breathing Engines
Report Number: R18EG3205
Subject Category: Research and Development
URL: https://www.jss.jaxa.jp/en/ar/e2018/9139/
Responsible Representative
Kouichi Okita, Director, Research and Development Directorate, Research Unit IV
Contact Information
Masatoshi Kodera (kodera.masatoshi@jaxa.jp)
Members
Masahiro Takahashi, Masatoshi Kodera, Masaaki Fukui, Toshihiko Munakata, Masaharu Takahashi, Sadatake
Tomioka, Takuto Miyaura, Takuya Arakawa, Hironobu Nishiguchi, Ko Kurihara, Kazunari HayashiAbstract
Recently, reusable rockets have been being studied to reduce the cost of space transportation systems
significantly. However, in order to extend the structural lifetime, it is necessary to operate them with relatively
low engine power, leading to a decrease in launch capability. Therefore, air-breathing engines such as scramjets
and rocket/scram combined cycle engines are promising to compensate the drawback. By using air in theatmosphere as an oxidizer, it becomes highly efficient, and it can be expected to maintain and improve the launchcapability even if it is reused. In this project, we will research and develop key technology for practical applicationof the engine.
Reasons for using JSS2
The following points are raised as problems of engine design by ground experiments. 1) There are limits to
reproducing various airflow conditions from takeoff to hypervelocity range. 2) Measured data is limited andcomplicated three-dimensional flow structure inside the engine can not be well identified. 3) Since the time andcost are limited, it is not easy to change the engine flow path configuration. Therefore, it is indispensable to utilize3D CFD as a design tool, and a supercomputer is required for performing numerous CFD works efficiently.
Achievements of the Year
Subject 1: The air vitiation effect that thrust performance in air conditions including water vapor (M6V) waslower than that in dry air (M6S) was observed in the Mach 6 combustion tests for a hydrogen fueled scramjetengine at the Ramjet Engine Test Facility (RJTF). In order to investigate the cause, three-dimensional RANS
analysis was carried out (Fig. 1).
Subject 2: RANS simulation corresponding to combustion tests of an ethylene-fueled scramjet combustor model
was conducted by using a JAXA in-house solver LS-FLOW. For validation of the present CFD, the profiles of thecombustion gas composition on the combustor exit plane predicted by the present CFD were compared with－280－

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experimental results measured by using a gas sampling rake probe. Influence of both the turbulent Schmidt number
and the C2H4-Air combustion mechanism adopted for the present CFD on the numerical results were examined.
The turbulent Schmidt number showed strong influence on the numerical results and the small value of 0.3 resulted
in better agreement with the experiment than 0.89 for the present case, in which the combustor operated in asupersonic combustion mode. It was also shown that the combustion mechanisms adopted for the CFD did notshow significant influence on the numerical results for the present case (Fig. 2).
Subject 3: A method to predict cooling capacity using pyrolysis of hydrocarbon fuel was constructed by CFD.
Two-dimensional axisymmetric CFD was performed including a decomposition reaction tailored to heating
experiments of dodecane in a circular tube. By devising the decomposition reaction model, it was possible topredict the endotherm with respect to the decomposition rate with good accuracy. However, it was found that there
might be problems in handling physical property values, since the decomposition rate was predicted to be much
lower than in experiments (Fig. 3).
Subject 4: As a tool to optimize the thrust performance of a dual-mode combustor according to the flight speed,
we considered a performance prediction method using CFD with relatively low computational costs. The prospectof being able to predict by a RANS method was obtained by devising boundary conditions etc.. On the other hand,
it was observed that the upstream extension of boundary layer separation was underpredicted (Fig. 4).

Fig. 1: Comparison between results in M6S and M6V conditions: contour plotsof Mach number (top) and temperatures (bottom).

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JAXA Special Publication JAXA-SP-19-003E

Fig. 2: Numerical results of a ethylene-fueled scramjet combustor flow-field; Static temperature(top), Mass fraction of H2O produced by combustion (middle), Mach number (bottom).

Fig. 3: Comparison between CFD and experiments in terms of correlation
between conversion rate and endotherm.

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JAXA Supercomputer System Annual Report (April 2018-March 2019)

Fig. 4: Comparison between CFD and experiments in terms of wall pressure distributions.
Publications- Non peer-reviewed papers
1) Kodera, M., Tomioka, S., “Investigation of Air Vitiation Effects on Scramjet Engine Performance,”
Proceedings of the 59th Conference on Aerospace Propulsion, 2019.
2) Takahashi, M., Nojima, K., Shimizu, T., Aono, J., Munakata, T., “Numerical Simulation of Ethylene-fueled
Scramjet Combustor Flows by Using LS-FLOW Solver,” Proceedings of the 50th Fluid Dynamics Symposium /The 36th Aerospace Numerical Simulation Symposium, 3C11, 2018.
3) Nishiguchi, H., Kodera, M., and Tomioka, S., “Performance Evaluation of a Dual-mole Combustor by theThree-dimensional RANS Simulation,” Proceedings of the 2019 Annual Meeting, Northern Branch of the Japan
Society for Aeronautical and Space Sciences, 2019.
4) Miyaura, T., Daimon, Y., Tomioka, S., “Study on Chemical Heat Sink of Liquid Hydrocarbon underSupercritical Condition,” Proceedings of the 2018 Annual Meeting, The Japan Society of Mechanical Engineers,
2018.
- Oral Presentations
1) Kodera, M., Tomioka, S., “Investigation of Air Vitiation Effects on Scramjet Engine Performance,” The 59th
Conference on Aerospace Propulsion, 2019.
2) Takahashi, M., Nojima, K., Shimizu, T., Aono, J., Munakata, T., “Numerical Simulation of Ethylene-fueled
Scramjet Combustor Flows by Using LS-FLOW Solver,” The 50th Fluid Dynamics Symposium / The 36th
Aerospace Numerical Simulation Symposium, 3C11, 2018.
3) Nishiguchi, H., Kodera, M., and Tomioka, S., “Performance Evaluation of a Dual-mole Combustor by theThree-dimensional RANS Simulation,” The 2019 Annual Meeting, Northern Branch of the Japan Society for
Aeronautical and Space Sciences, 2019.
4) Miyaura, T., Daimon, Y., Tomioka, S., “Study on Chemical Heat Sink of Liquid Hydrocarbon underSupercritical Condition,” The 2018 Annual Meeting, The Japan Society of Mechanical Engineers, 2018.
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Usage of JSS2

Computational Information
Process Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

640 - 1280

Elapsed Time per Case

400 Hour (s)Resources Used
Fraction of Usage in Total Resources*1 (%): 2.09
Details
Computational Resources
System Name

Amount of Core Time(core x hours)

Fraction of Usage*2 (%)

SORA-MA

19,067,821.96

2.33

SORA-PP

84,048.53

0.67

SORA-LM

674.690.31

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage Assigned (GiB)

Fraction of Usage*2 (%)/home158.64

0.16/data

3,899.67

0.07/ltmp9,814.46

0.84

Archiver Resources
Archiver Name

Storage Used (TiB)

J-SPACE

Fraction of Usage*2 (%)
1.50

0.05

*1

: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System,and Archiver).
*2: Fraction of Usage: Percentage of usage relative to each resource used in one year.

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