Numerical analysis on reactive blast waves during auto-ignition process for hypergolic propellants

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDG20500

Subject Category: Research and Development

Responsible Representative: Koji Matsumoto, Research and Development Directorate, Research Unit II
Contact Information: Noritaka Sako(sako.noritaka@jaxa.jp)
Members: Noritaka Sako

Abstract

In bipropellant thrusters that use hypergolic liquid fuel and liquid oxidizer as propellants, an explosive ignition phenomenon accompanied by a steep pressure rise—referred to as a hard start—has been observed in past thruster development activities, differing from normal ignition behavior. In the worst case, this hard start can directly lead to catastrophic damage. The objective of this project is to clarify the mechanism of hard start through numerical simulations on JSS3, and to obtain findings that will contribute to establishing design guidelines for its mitigation.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

The hard start phenomenon involves blast-wave propagation accompanied by combustion reactions, and the use of large-scale computational resources such as JSS3 is indispensable for numerically solving the fluid dynamics and combustion reactions simultaneously.

Achievements of the Year

Blast-wave analyses were conducted for both non-reactive and reactive fields with the same amount of energy applied to the ignition source. For the reactive field, combustion simulations were performed incorporating a detailed chemical reaction mechanism for hydrazine/dinitrogen tetroxide. The propagation process of the blast-wave (shock-wave) front obtained from the numerical simulations was compared with experimental results using actual propellants. The results showed that the reactive-field simulations reproduced the experimental trends more accurately, suggesting that heat release reactions behind the wave front play an important role in blast-wave propagation during a hard start.

Publications

N/A

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: OpenMP
Number of Processes: 4 - 132
Elapsed Time per Case: 350 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.02

Details

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

Computational Resources
System Name	CPU Resources Used (Core x Hours)	Fraction of Usage*2(%)
TOKI-SORA	0.00	0.00
TOKI-ST	8192.32	0.01
TOKI-GP	0.00	0.00
TOKI-XM	1309.49	0.45
TOKI-LM	4583.40	0.35
TOKI-TST	108796.70	1.78
TOKI-TGP	0.00	0.00
TOKI-TLM	0.00	0.00

File System Resources
File System Name	Storage Assigned (GiB)	Fraction of Usage*2(%)
/home	0.00	0.00
/data and /data2	0.00	0.00
/ssd	0.00	0.00

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	0.00	0.00

*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.

ISV Software Licenses Used

ISV Software Licenses Resources
	ISV Software Licenses Used (Hours)	Fraction of Usage*2(%)
ISV Software Licenses (Total)	564.00	0.40

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.