A Study on Detonation Driven High Enthalpy Expansion Tube for Hyperbolic Orbital Velocity

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On the atmospheric reentry of spacecraft of sample return mission or planet entry of various probes, extremely severe aerodynamic heating to the spacecraft occur. The incoming Mach number to the spacecraft is more than 20 and temperature behind shock wave is over 10,000 degrees, In this conditions air is dissociated and ionized and chemically and thermally non-equilibrium flows around the spacecraft should be investigated. For the study of such high enthalpy flow experimental facility of the ground testing are necessary.The purpose of the present study is to survey the possibility and conditions of high enthalpy flow test facility and build such a test facility. In the present study a new type of test facility is proposed. The high pressure and high temperature gas, which is produced with detonation, is used as driver gas of shock tube. Next to the shock tube a acceleration tube is attached in order to accelerate the high speed flow to hyper-orbital velocity. Since the proposed test fa … More cility has no flow stagnation condition and hyper-orbital velocity can be realized by flow acceleration, the test facility could produce hyper-velocity flow without dissociation and ionization. In the present studies the following studies have been conducted.1) Characteristics of expansion tube are investigated and carefully designed. The expansion tube succeeded to produce maximum shock Mach number of 34.5 and estimated flow velocity is 9.8 km/s, which is hyper-velocity.2) Characteristics of detonation tube is investigated and carefully designed. The detonation tube with initiation tube is used in order to produce high pressure and high temperature gas. The stoichiometric mixture of hydrogen gas and oxygen gas is used for the testing gas. The detonation tube tube with initiation tube could produce Chapman-Jouget detonation yelocity.3) The combination of the detonation tube with initiation tube and shock tube are produced and tested in order to obtain high shock Mach number. The combination test facility could produce shock Mach number of 7.4 and this shock Mach number is possible to increase the initial pressure of stoichiometric mixture of hydrogen gas and oxygen gas of detonation tube. Less