PS12
小型超音速飛行実験機ＬＯＸタンク向け推薬捕捉機構の開発
Study on Examination of Propellant Supply System for
LOX Tanks in Small-scale Supersonic Flight Experiment八十島尊, 田中秀龍, 高橋輝星, 今井良二, 中田大将, 内海政春
Takeru YASOJIMA1, Hidetatsu TANAKA1, Kira TAKAHASHI1, Ryoji IMAI1, Daisuke NAKATA1
and Masaharu UCHIUMI1
1

室蘭工業大学，Muroran Institute of Technology

1. Introduction
The Aerospace Plane Research Center in Muroran Institute of Technology is development the small-scale
supersonic flight experiment aircraft as a flying test bed for a technical demonstration in high-speed flightenvironment. In the small-scale supersonic flight experiment aircraft, the liquid supplying system forbioethanol (BE) and liquid oxygen (LOX) by nitrogen pressurant has been considered. However, it is fearedthat the risk of adverse effects on the attitude control of the aircraft and the propulsion system by the inclusionof pressurized gas in the supplied LOX increase due to sloshing by the acceleration during flight.
The purpose of this study is to research and develop the propellant management device (PMD) that cansuppress the entrainment of pressurized gas in the LOX tank. In this study, measurements of bubble point
pressure were taken to determine the specifications of PMD.
2. Theory and Methodology
PMD in this research uses a metal mesh to take advantage of the surface tension of the liquid. When themesh gets wet, the surface tension of the liquid forms a liquid film on the mesh surface, and this film separates
the gas and liquid, thereby suppressing gas entrainment. The pressure when gas entrainment occurs is thebubble point pressure, which is given by the following equation (1). 1)
𝑃𝐵𝑃 =4𝛾𝑛 × (1 − 𝑛𝐻𝑜𝑡 (𝑇𝐺𝑎𝑠 − 𝑇))𝐷 𝑠𝑎𝑡(1)Where 𝑃𝐵𝑃 is bubble point pressure, 𝛾 is the surface tension of the liquid, 𝐷 is the mesh diameter,
𝑛𝑠𝑎𝑡 ,𝑛𝐻𝑜𝑡 are coefficients, 𝑇𝐺𝑎𝑠 is the temperature of the pressurized gas and 𝑇 is the temperature of theliquid. Theoretically, gas entrainment can be prevented if the gas pressure does not exceed the bubble point
pressure.

1 of 4

Figure 1.

Liquid film on metal mesh.

3. Measurement of bubble point pressure
In this experiment, the bubble point pressure is measured with the stainless steel (SS) 325 × 2300 Dutch Twill
screen. Figure. 2 shows the piping system of the experimental apparatus, Figure. 3 shows the experimentalapparatus, Figure. 4 shows the test section, and Figure.5 shows metal mesh. As shown in Figures. 4 and 5, themetal mesh was inserted between a metal plate with holes and a polycarbonate cylindrical block to visualize
the generation of bubbles from the gas supply area and the mesh surface. liquid nitrogen (LN₂) was used as
the simulated liquid and helium gas (GHe) as the pressurized gas. After the metal mesh was immersed in LN₂in a cylinder upward to form a liquid film, GHe was supplied, and when bubbles were generated from themetal mesh, the GHe supply was stopped and the maximum pressure value thereafter was recognized as thebubble point pressure. To reduce the temperature difference between LN₂ and GHe at the metal mesh, GHe ispassed through a helical coil tube immersed in LN₂ before being fed into the metal mesh.

Pressure gauge

Test section

Figure 2.

Piping system of the experimental
apparatus.

Figure 3.

Appearance of the experimental
apparatus.

2 of 4Metal mesh

Figure 4.

Test section.

Figure 5.

Metal mesh.

4. Experimental results
Figure.6 shows the pressure change during No.1 bubble point pressure experiment. The GHe supply wasstopped when bubbles were generated from the metal mesh. The maximum pressure after that was 176
seconds after the start of the experiment and was 3.207kPa. A total of four similar experiments were conducted,
and Table 1 shows the bubble point pressure test results and their average values. As a result, the bubble point
pressure was 3.201 kPa when the 325 × 2300 Dutch Twill screen was immersed in LN₂. Entering the value forthe present experimental conditions into equation (1) yields 2.677 kPa, which is smaller than the value obtainedin the present experiment. A possible reason for these discrepancy could be the difference between the meshdiameter used in the experiments and the mesh diameter used in the calculations.

Figure 6.

Pressure changes during No.1 bubble point pressure experiment

3 of 4

Table 1.

Bubble point pressure test results and their average values

5. Conclusion
To determine the specifications of PMD, bubble point pressure experiments were conducted with the flat
metal mesh. Therefore, bubble point pressure was successfully measured in cryogenic liquids.
In the future, we plan to conduct bubble point pressure experiments with the cylindrical metal mesh, which
is being considered for use as an internal device in small-scale supersonic flight experiment.
References1)

Jason W. Hartwig, Yasuhiro Kamotani：The static bubble point pressure model for cryogenic screen channel liquid
acquisition devices，International Journal of Heat and Mass Transfer 101 (2016), 502–516© 2024 by the authors. Submitted for possible open access publication under
the terms and conditions of the Creative Commons Attribution (CC BY) license(http://creativecommons.org/li censes/by/4.0/).

4 of 4