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TEXUS 観測ロケット 60 号機を用いた液滴冷炎に関する微小重力実験（Phoenix-2）実施概要
Outline of the Microgravity Experiments on Droplet
Cool Flame (Phoenix-2) Using TEXUS Sounding Rocket#60
田辺光昭 1, 菅沼祐介 1, 野村浩司 1, 齊藤允教 1, 家村和輝 1, 髙橋晶世 1, 髙橋賢一 1, 森上修 2, 安藤詩音 2,三上真人 3, 後藤芳正 4, 山村宜之 4, 野倉正樹 4, 山本信 4, Noelia M. FIGUEIRA 5, Florian MEYER5,Christian EIGENBROD5, 石川毅彦 6, 菊池政雄 6, 嶋田徹 6, 稲富裕光 6
Mitsuaki TANABE1, Yusuke SUGANUMA1, Masanori SAITO1, Kazuki IEMURA1, Akiyo
TAKAHASHI1, Kenichi TAKAHASHI1, Osamu MORIUE2, Shion Ando2, Masato MIKAMI3, Yoshimasa
GOTO4, Nobuyuki YAMAMURA4, Masaki NOKURA4, Shin YAMAMOTO4, Noelia M. FIGUEIRA5,Florian MEYER5, Christian EIGENBROD5, Takehiko ISHIKAWA6, Masao KIKUCHI6, Toru
SHIMADA6 and Yuko INATOMI6
日本大学，Nihon University,
九州大学，Kyushu University,
3 山口大学，Yamaguchi University,
4IHI 検査計測，IHI Inspection & Instrumentation Co. Ltd.,5ZARM，Bremen University,
6 宇宙航空研究開発機構，JAXA,
12The TEXUS-60 sounding rocket experiments on droplet cool flame had been planned and defined as the coreactivity of the Japan-German joint research project, Phoenix-2. The project is recognized as one of the JAXADLR collaborative sounding rocket experiment since 2017. Preparative work had been done as a Front-loading
Research by ISAS Space Utilization Science Committee. The flight model development and the flight campaign
have been promoted by ISAS Small Scale Project and Nihon University President Grant Initiative. Cool flameis a low temperature flame that leads the spontaneous ignition of hot flame. The cool flame dynamics isinvestigated, for it controls the ignition, and hence, abrupt heat release that may destroy combustors. In theflight experiments, five patterns (Fig. 1) of fuel droplet array are generated onto fine SiC suspenders and areinserted into two furnaces of different temperature (590 / 570K) to spontaneously ignite cool flames. n-Decane
is employed as fuel, for it is the major component of SAF (Sustainable Aviation Fuel) and is known to havecool flame. Air at atmospheric pressure is used as the ambient. The induction time, the location of flame onset,
burning rate and other dynamical characteristics of cool flames are planned to be determined through highresolution back-lit imaging and high-speed HCHO luminescence imaging as a cool flame marker. The
experimental module, DCU-2 is developed by the Japanese team and the German team developed the cool
flame direct-imaging system and the bus-module. The sounding rocket was launched in March, 2024 at theEsrange Space Center (Table 1). The planned data was successfully obtained for the furnace with the lower
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temperature. Cool flame was found to spontaneously ignite at the furnace at 570K, being the lowest
temperature ever achieved, for the sufficiently long microgravity duration of the rocket experiments (Fig. 2).
The outline of the experiments and the steps to the launch is going to be presented.

Figure 1. Tested droplet arrangement.

Table 1. TEXUS-60 flight summary.

Launch Site

Esrange Space Center, SSC

Launched

09.45 (UTC) 24 March 2024

Rocket Type

VSB-30Payload Mass

400 kgApogeum

251.7 kmFigure 2. Spontaneously ignited cool flames as a HCHO luminescence image(false color, 570 K, pattern 5).

Acknowledgements
This study is supported by ISAS-JAXA Small-Scale Project, The Front-Loading Project, JSPS KAKENHI Grant Number 17K06950,19K04843, and 21K14347, 24K07887, and by Nihon University President Grant Initiative. The authors express sincere gratitude toDLR and Airbus team for their outstanding contributions.
© 2024 by the authors. Submitted for possible open access publication under theterms and conditions of the Creative Commons Attribution (CC BY) license(http://creativecommons.org/li censes/by/4.0/).

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