Experimental and theoretical evaluation of hydrogen cloud explosion with built-in obstacles

Abstract

This work is aimed at evaluating hydrogen cloud explosion with built-in obstacles experimentally and theoretically. The flame front evolution is captured using infrared filtering technology and the explosion overpressure at four monitoring points is measured using free-field sound pressure sensor. The laminar flame model and turbulent flame model are established to theoretically predict maximum explosion overpressure in advance. The results demonstrated that the flame acceleration of hydrogen cloud explosion with built-in obstacles is attributed to mutual promotion of flame instabilities and obstacle-induced turbulence. The effects of built-in obstacles on maximum flame front velocity is relatively limited and maximum value of flame wrinkling factor is ΞΔ,max = 3.64. As the distance between pressure sensor and ignition source increases, the maximum explosion overpressure, positive overpressure impulse and absolute value of negative overpressure impulse are decreased monotonously. The positive overpressure and negative overpressure are mainly affected by steel pipe number in vertical and horizontal direction, rather than length of steel pipe cross-section. The velocity of explosion overpressure propagating in the air is c = 350.88 m/s. The maximum explosion overpressure should be significantly underestimated by laminar flame model, the turbulent flame model could be used to satisfactorily predict maximum explosion overpressure at four monitoring points.