Investigation of the Uniformity of Explosive Shock Wave Fronts in Variable Cross-Section Shock Tubes

A shock tube can simulate the explosive shock environment and is often used in research on biological injury mechanisms and the development and testing of protective technologies. A shock tube is usually composed of a driving section, a driven section, and a test section, and can generate shock waves by breaking a membrane with high-pressure gases (nitrogen, helium, or compressed air) or hydrogen-oxygen detonation. Studies have shown that shock waves will rapidly expand at the exit of the driven section of the shock tube, which can easily cause unevenness in the shock wave front at this location, affecting the test and research. Therefore, this study uses pressure sensors to study the non-uniformity at the exit of the shock tube. The experimental results show that when the free-field pressure peak value is 80 kPa, the shock wave is relatively uniform within 6 cm of the exit of the shock tube; when the free-field sensor is fixed at a certain distance, the non-uniformity of the simulated explosive shock wave generated by the shock tube increases as the free-field pressure peak value increases. This study reveals the non-uniform characteristics of the shock wave at the exit of the shock tube, which has important implications for improving the accuracy and reliability of shock tube experiments.