JAXA Supercomputer System Annual Report April 2020-March 2021

Report Number: R20ETET50

Subject Category: Skills Acquisition System

PDF available here

• Responsible Representative: AOYAMA Takashi, Director, Aeronautical Technology Directrate, Numerical Simulation Research Unit
• Contact Information: Kazuya Uchiyama(kazuchiyama@toki.waseda.jp)
• Members: Kazuya Uchiyama

Abstract

As the first stage of research and development aimed at realizing hypersonic aircrafts, High-Mach Integrated Control Experiment (HIMICO) is underway by JAXA and universities. In this experiment, the ramjet engine using gaseous hydrogen fuel will be mounted on the experimental aircraft. Self-ignition has not been successful in the combustion tests since 2017, and there are problems such as lack of experimental data and differences between flight conditions and experimental conditions due to the limitation of the number of experiments and the limitations of the combustion experimental facilities. Therefore, numerical analysis is performed to interpolate the experimental data and to grasp the combustion phenomena such as ignition and flame holding.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

In LES considering detailed chemical reactions on a experimental scale with more than 10 million grid points, the computational cost is high. By using a JAXA supercomputer capable of parallel processing, analysis became possible within a realistic time.

Achievements of the Year

From the analysis results up to last year, it was found that the wall temperature of the injector that supplies gaseous hydrogen fuel into the combustor affects the ignition. Based on this, we analyzed the case where self-ignition did not occur during the combustion test (mainstream air temperature 738 K), setting the temperature boundary condition of the injector wall to a low temperature (300 K) isothermal wall, and the presence or absence of ignition was verified. As a solver, we used a reactive flow solver developed by our laboratory based on JAXA's fast fluid analysis solver, FaSTAR, implementing species transport equations and Arrehenius equation. As a result of the analysis, ignition was confirmed, but the time to ignition was about 2.2 times longer than the case (mainstream air temperature 800 K) analyzed last year.

Fig.1: Outline figure of ramjet engine for HIMICO

Fig.2: Outline figure of injector

Fig.3: Instant temperature distribution

Fig.4: Time variation of the average temperature distrubution and the average H radical mol fraction distribution behind the injector

Publications

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Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: N/A
• Number of Processes: 1024
• Elapsed Time per Case: 250 Hour(s)

Resources Used(JSS2)

Fraction of Usage in Total Resources*1(%): 0.38

Details

Please refer to System Configuration of JSS2 for the system configuration and major specifications of JSS2.

*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.

Resources Used(JSS3)

Fraction of Usage in Total Resources*1(%): 0.01

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

*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.

JAXA Supercomputer System Annual Report April 2020-March 2021