Demonstration of a High-Speed Endwall Imaging Setup for Studying Ignition Phenomena in a Shock Tube

Abstract

Inhomogeneous combustion events in shock-tube experiments can be difficult to identify and can be an obstacle to data collection at certain conditions where such nonideal effects are encountered. Understanding these undesirable combustion events, which typically occur for undiluted mixtures at higher pressures and lower temperatures, allows researchers to better predict combustion irregularities at such conditions. A new addition to the High-Pressure Shock Tube facility at the TEES Turbomachinery Laboratory at Texas A&M University (TAMU) has been designed and fabricated to help image and study these undesirable events. This addition to the shock-tube facility includes an endwall window that has been designed to allow high-speed imaging during combustion events using a LaVision HighSpeed IRO intensifier connected to a Photron FASTCAM SA-Z high-speed camera. The endwall window housing is fabricated out of 303 stainless steel and incorporates the use of a 25-mm thick sapphire or a 90-mm thick fused quartz window for optical access. The design also allows for simultaneous pressure measurements through 4 side wall pressure ports located near the endwall. The new endwall imaging addition allows for test pressures from 1 to 100 atm and between 600 and 4000 K behind the reflected shock wave. This thesis demonstrates the design, manufacture, and testing of the new facility. Details of the experimental setup and procedures are provided, and results from reflected-shock ignition experiments are presented. Results shown herein include studies of fuel mixtures of argon-diluted methane, real-fuel-air methane, carbon dioxide-diluted syngas, argon-diluted hydrogen, and real-fuel-air propane. Post-reflected shock temperatures and pressures ranged from near 1 atm to around 45 atm with temperatures ranging from 950 to 1300 K for these studies.