Development of a large-diameter, double-diaphragm, single-pulse converging shock tube

A large-diameter, double-diaphragm, single-pulse converging shock tube crafted for kinetic studies of high-pressure reactions is described. A three-dimensional converging structure connecting the driven section and the test section was designed, which reduced the inner diameter of the shock tube gradually from 210 to 105 mm, effectively enhancing the shock intensity, meanwhile maintaining a stable pressure region following the reflected shock wave. A novel disk-shape dumper plate was proposed to replace the conventional dump tank, enabling the suppression of secondary temperature rise induced by the re-reflection of the reflected shock wave. A switchable test section was designed to adapt to substituted tubes of conventional constant-diameter shock tube (CDST) and a novel converging shock tube (CST). The conventional CDST was primarily for testing the effects of large diameter characteristics as well as performing validation or control experiments for CST. The CST facility was validated by single-pulse functionality, shock wave repeatability, and capability to generate high Mach numbers. The characterized pressure profiles showed that the large-diameter configuration was able to generate nearly ideal pressure curves, and the three-dimensional converging structure notably promoted the shock intensity without disturbing the flow field. Extensive repeatability experiments were conducted in both CST and CDST with single- and double-diaphragm configurations, and reliability experiments for high-pressure ignition delay time were performed. The results indicated that both the CST and CDST were exceptionally reliable in generating strong shock waves and mitigating additional shock wave pulses, making them useful equipment for advanced high-pressure kinetic studies.