UBC Theses and Dissertations
The production of hypersonic shock waves in an electrothermal diaphragm shock tube Phillips, Malvern Gordon Rutherford
The operation of a diaphragm shock tube of 5 cm inside diameter in which the driver gas is heated by the discharge of electrical energy ( ~ 10³ joules) is analyzed in detail. A technique is described for the measurement of the heated driver gas pressure and empirical relations are obtained which enable the shock speed to be calculated from a knowledge of the discharge voltage and test gas pressure. Using helium driver gas initially at atmospheric pressure, shock Mach numbers of about 20 are obtained in argon at an initial pressure of about 1 Torr. The separation of shock front and contact surface is analyzed by means of a convenient shock reflection technique using a smear camera. The properties of the shock-heated gas are shown to agree with the predictions of standard shock wave theory, which yields a temperature of about 1.3•10⁴°K and an electron density of about I0¹⁷ cm⁻³ for the case of a Mach 20 shock in argon at 0.5 Torr. In this case the shock-heated gas sample is observed to be about 5 cm in length at a position 1.2 meters from the diaphragm.
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