A miniature high repetition rate shock tube

Abstract

A miniature high repetition rate shock tube with excellent reproducibility has been constructed to facilitate high temperature, high pressure, gas phase experiments at facilities such as synchrotron light sources where space is limited and many experiments need to be averaged to obtain adequate signal levels. The shock tube is designed to generate reaction conditions of T > 600 K, P < 100 bars at a cycle rate of up to 4 Hz. The design of the apparatus is discussed in detail, and data are presented to demonstrate that well-formed shock waves with predictable characteristics are created, repeatably. Two synchrotron-based experiments using this apparatus are also briefly described here, demonstrating the potential of the shock tube for research at synchrotron light sources.

Initiation reactions in the high temperature decomposition of styrene

“…The ANL-HRRST is a miniature shock tube designed for high pressure experiments in the lab and at synchrotron facilities. 39 The driver section is a stainless steel chamber (volume: 20 cm 3 ) equipped with a solenoid actuated valve that separates the driver and driven sections. The driven section has a bore of 6.35 mm and length of 879 mm.…”

“…Experiments were performed in two diaphragmless shock tubes that have been fully described previously. One is referred to as the DFST 37,38 (diaphragmless shock tube) and the other as the ANL-HRRST 39 (Argonne National Laboratory-High Repetition Rate Shock Tube). Both shock tubes are coupled via differentially pumped molecular beam sampling (MBS) systems to time-offlight mass spectrometers (TOF-MS).…”

“…Details of the procedure can be found in prior publications. [39][40][41] For every experiment, initial conditions and considerable data regarding operation of the shock tube are recorded along with the mass spectra. These data permit for post-processing of experiments closely binned by experimental condition.…”

“…Both shock tubes create very reproducible reaction conditions that permit signal averaging to improve signal/noise. [37][38][39][40] From the DFST/TOF-MS experiments, 5-10 experiments were ensemble averaged; whereas, 100 experiments for each data point were ensemble averaged in the ANL-HRRST/TOF-MS work.…”

“…The consumption of reagent mixture in the ANL-HRRST was sufficiently large that an alternate method of preparation was employed using a novel batch/flow mixing apparatus which has been previously described. 39,41,50 In short, reagent mixtures were prepared on demand and delivered via a vacuum regulator to the driven section of the ANL-HRRST. Part of the argon stream entering the mixing apparatus was diverted through a high-pressure bubbler containing liquid styrene at room temperature.…”