Study on Liquid Management Technology in Water Tank for Propulsion System Utilizing Aluminum and Water Reaction (Improvement of Liquid Acquisition Performance by Hydrophilic Coating in Metallic Tank)

In order to use hydrogen as a fuel for spacecraft propulsion system, utilization of aluminum and water reaction system is considered. Liquid-gas separation is necessary for water tank in this propulsion system. The purpose of this study is to confirm the applicability of water to the surface tension liquid acquisition mechanism in tank by improving wettability using a silica coating. It was demonstrated that silica coating could improve the wettability of water against metallic material applied to practical tanks. By the microgravity experiment using drop tower facility, it was confirmed that water in tank could be acquired on the liquid outlet by vane device with silica coating

Propulsive Performance and Heating Environment of Rotating Detonation Engine with Various Nozzles

Geometric throats are commonly applied to rocket combustors to increase pressure and specific impulse. This paper presents the results from thrust measurements of an ethylene/gas-oxygen rotating detonation engine with various throat geometries in a vacuum chamber to simulate varied backpressure conditions in a range of 1.1–104 kPa. For the throatless case, the detonation channel area was regarded to be equivalent the throat area, and three throat-contraction ratios were tested: 1, 2.5, and 8. Results revealed that combustor pressure was approximately proportional to equivalent throat mass flux for all test cases. Specific impulse was measured for a wide range of pressure ratios, defined as the ratio of the combustor pressure to the backpressure in the vacuum chamber. The rotating detonation engine could achieve almost the same level of optimum specific impulse for each backpressure, whether or not flow was squeezed by a geometric throat. In addition, heat-flux measurements using heat-resistant material are summarized. Temporally and spatially averaged heat flux in the engine were roughly proportional to channel mass flux. Heat-resistant material wall compatibility with two injector shapes of doublet and triplet injection is also discussed

Drag Reduction on the Basis of the Area Rule of the Small-scale Supersonic Flight Experiment Vehicle Being Developed at Muroran Institute of Technology

A small-scale supersonic flight experiment vehicle (OWASHI) is being developed at Muroran Institute of Technology as a flying testbed for verification of innovative technologies for high speed atmospheric flights which are essential to next-generation aerospace transportation systems. The second-generation configuration M2011 of the vehicle with a single Air Turbo Ramjet Gas-generator-cycle (ATR-GG) engine has been proposed. Its transonic thrust margin has been predicted to be insufficient, therefore drag reduction in the transonic regime is quite crucial for attainability of supersonic flights. In this study, we propose configuration modifications for drag reduction on the basis of the so-called area rule, and assess their effects through wave drag analysis, wind tunnel tests, and CFD analysis. As a result, the area-rule-based configurations have less drag than the baseline configuration M2011. However, the effects of the proposed bottleneck on the fuselage below the main wing are smaller than predicted. It would be caused by the drag due to separation and shocks around the bottleneck. It is necessary to redesign the area-rule-based bottleneck to be smoother