Study on Performance of Detonation-Driven Shock Tube

A detonation-driven shock tube firstly designed by H. R. Yu is considered to be a useful apparatus for producing high-enthalpy flow. In this apparatus, a strong shock wave is generated by detonating an oxygen-hydrogen mixture (oxy-hydrogen) and the driver gas temperature and pressure are extremely high compared with those of a conventional shock tube. However, the structure of the detonation wave is not uniform, e. g., the detonation wave has three-dimensional cellular structures and multiple transverse waves. Furthermore, the detonation wave is followed by a Taylor expansion fan and the performance of detonation-driven shock tube is not well understood. In this preliminary study, a detonation-driven shock tube is constructed and its performance is experimentally investigated by measuring pressure histories and the profile of the ionization current behind the detonation wave. As a result, (i)the pressure history of the detonation wave is clarified and shows reasonable agreement with the result obtained by the KASIMIR shock tube simulation code. (ii)The propagation velocity of the detonation wave coincides well with the theoretical prediction assuming a Chapman-Jouguet detonation wave. (iii)The equivalence ratio of the oxy-hydrogen mixture to produce the highest Mach number of the shock wave is evaluated to be φ approximately equal to 1.7.