Study on the pressure relief law of multistage relief isolator

The relationship between the pressure relief efficiency of a multistage pressure relief isolator and three geometric parameters—the relief groove size (w), the spacing between grooves (Δx), and the number of sections (n)—is investigated in this study. A mathematical model based on local pressure differences is proposed to describe the interaction between these four variables. By analyzing the relief law of the backpressure wave in the isolator, it is known that the local pressure difference is the key factor that dominates the relief degree, and the mathematical model can reflect this physical law. Using 45 simulation results for model fitting, the model's root mean square error is approximately 0.037. Correlation analysis reveals that, for a constant initial backpressure generated by detonation combustion, the structural parameters of the pressure relief isolator are all negatively correlated with backpressure. Among these, the correlation between backpressure and the number of sections is the most significant, with a Spearman coefficient of −0.641. Additionally, when the values of w and Δx are significant, further increases in these parameters have a limited impact on the relief effect. Therefore, the most effective design approach is to minimize w, Δx, and n while still achieving the desired pressure relief, preferring a multistage relief approach rather than maximizing any single parameter. Experimental results also suggest that environmental conditions can influence the model's coefficients, requiring recalibration for each specific condition. The fitted coefficients should, therefore, be applied only within the context of the corresponding environmental conditions.