Diaphragmless Single-Pulse Shock Tube For High-Temperature Chemical Kinetics Studies

Single-pulse shock tubes are effective tools for measuring chemical kinetics at high temperatures, typically (900-1400) K. However, the use of a diaphragm for shock generation leads to significant shock-to-shock inconsistencies in temperature for a constant initial pressure ratio across the discontinuity. Diaphragms also require replacement after each shock and demand care in cleaning to ensure that the fragments do not contaminate the apparatus. A piston-driven valve design is presented that leads to a highly reproducible postreflected shock temperatures (0.41% at 1147 K and 0.61% at 967 K) in a single pulse varying from (500 to 1200) mu s in width over the temperature range of interest. Characterization of the valve was accomplished using both shock-speed measurements and independent measurements of the pulse temperature using reference thermal decomposition reactions.