Carbon Formation from Acetylene in the Shock Tube

Citation

Bennett, Eugene Newell (1956) Carbon Formation from Acetylene in the Shock Tube. Engineer's thesis, California Institute of Technology. doi:10.7907/GB80-GE14. https://resolver.caltech.edu/CaltechETD:etd-03182004-142409

Abstract

The use of the shock tube for the study of carbon formation from acetylene has been considered theoretically and studied experimentally. In the calculations, the state of the gas is determined behind incident and reflected shocks for a wide range of shock strengths and for various excitation models of the internal degrees of freedom. A simple mechanism has been assumed for the thermal decomposition, namely the formation of solid carbon and hydrogen. Estimates are presented for the minimum times spent by the gas in a uniform state at the elevated temperatures behind reflected shocks. The shock strengths required to initiate decomposition of acetylene at various pressures have been investigated experimentally. Temperature estimates and shock velocity measurements suggest that the effective specific heat ratio approaches the equilibrium value. Spectroscopic studies have been carried out to determine the light emitted in a narrow wave length region during chemical decomposition behind reflected shocks. The results show that the intensity distribution follows the black-body emission law. Therefore, a two-color method may be used in future studies for determining the temperature as a function of time behind carbon forming shocks.

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