Diaphragmless shock wave generators for industrial applications of shock waves

Shock Waves (Impact Factor: 0.89). 06/2011; 21(3):301-306. DOI: 10.1007/s00193-010-0296-5


The prime focus of this study is to design a 50mm internal diameter diaphragmless shock tube that can be used in an industrial
facility for repeated loading of shock waves. The instantaneous rise in pressure and temperature of a medium can be used in
a variety of industrial applications. We designed, fabricated and tested three different shock wave generators of which one
system employs a highly elastic rubber membrane and the other systems use a fast acting pneumatic valve instead of conventional
metal diaphragms. The valve opening speed is obtained with the help of a high speed camera. For shock generation systems with
a pneumatic cylinder, it ranges from 0.325 to 1.15 m/s while it is around 8.3 m/s for the rubber membrane. Experiments are
conducted using the three diaphragmless systems and the results obtained are analyzed carefully to obtain a relation between
the opening speed of the valve and the amount of gas that is actually utilized in the generation of the shock wave for each
system. The rubber membrane is not suitable for industrial applications because it needs to be replaced regularly and cannot
withstand high driver pressures. The maximum shock Mach number obtained using the new diaphragmless system that uses the pneumatic
valve is 2.125 ± 0.2%. This system shows much promise for automation in an industrial environment.

KeywordsDiaphragmless shock tube–Shock waves–Diaphragmless shock wave generators–Diaphragmless drivers

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    ABSTRACT: This paper reports on the performance evaluation of a rapid opening valve assisted by magnetic force for a new diaphragmless shock tube. The movement direction of the piston valve in the driver section of the present device crosses the axis of a shock tube at right angles so that the piston valve is accelerated before the shock tube is opened. In addition, a permanent magnet installed in the high-pressure chamber increases the pressure difference between both sides of the piston valve. The opening time of the shock tube inlet and pressure variations in the shock tube are measured experimentally. Detailed driving process of the present device is investigated using a one-dimensional theoretical calculation. The experimental and computational results show that the opening time of the shock tube inlet can be shortened about 30% when magnetic force is applied to the piston valve. The theoretical results suggest that the performance of the driver section is under better condition.
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