氢氧点火试验中边界层效应的作用机理研究

In shock tube experiments conducted under real physical conditions, the boundary layer effects induced by viscous forces interfere with the physical environment following the reflection shock wave. This study employed shock tube experiments to measure the pressure rise after the reflection shock wave during hydrogen-oxygen ignition experiments, specifically attributing this rise to boundary layer effects. Additionally, we incorporated chemical reaction kinetics simulations to quantitatively analyze the impact of these non-ideal effects on the measurement of hydrogen-oxygen ignition parameters. The experiments utilized a low-concentration hydrogen-oxygen mixture as fuel, with argon serving as the dilution gas, resulting in a volume ratio of hydrogen, oxygen, and argon of 3. 85%:3. 846%: 92. 304% . Nitrogen-helium mixed gas was utilized as the driving gas in the experiments. By adjusting the filling pressure of the driven section and the mixing ratio of the driving gas, we successfully regulated the temperature and pressure following the reflected shock wave in the test section. The experimental results indicate that a pressure rise phenomenon is commonly observed after the reflection shock wave, with the pressure rise rate typically ranging from 1% to 5% . By developing a predictive model that incorporates the time-varying characteristics of pressure, we significantly improved the accuracy of ignition delay time predictions. This model demonstrated that approximately 85% of the error in traditional constant-pressure, constant-volume prediction results stemmed from neglecting the impact of the pressure rise. The study also revealed that the extent of the pressure rises influence is linked to both the initial pressure and the characteristics of the experimental equipment. Additionally, the measurement error in ignition delay time resulting from the pressure rise after the reflection shock wave tends to increase as the shock tube diameter decreases. This research systematically elucidated the mechanisms underlying experimental data deviations caused by non-ideal effects in reaction flow field experiments utilizing shock tubes. Furthermore, we developed an error correction method based on the analysis of these non-ideal effects, thereby enhancing the ability to interpret data from non-ideal shock tube ignition and explosion experiments.