UBC Theses and Dissertations
Heat waves in an electrothermal shock tube Armstrong, Bruce Allan
The fluid flow in an electrothermal shock tube powered with a constant current was compared to that predicted by a heat wave model and found to be in qualitative agreement. An empirical heating characteristic, obtained experimentally from gas dynamical measurements, was verified with spectroscopic and velocity measurements indicating the flow is also in quantitative agreement with the model. Using a two step current pulse we launched double shock waves in argon with a subsonic heat wave. The interaction of these shock waves agreed very well with theory. Increasing the current in the second step created faster second shock waves until some limiting value of the current was reached, after which a second shock could no longer be produced. Rather, a supersonic heat wave was created which burned through the previously shock-compressed material. The velocities of the second shocks were in reasonable quantitative agreement with predictions of the heat wave theory, indicating again the flow in the shock tube is well described by the model. It was shown that the resulting fluid flow, after all the waves had interacted, did not depend on the history of the power pulse, only on its final magnitude.
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