Influence of vent size and vent burst pressure on vented ethylene-air explosion: Experimental and numerical study

Abstract

This paper describes the numerical simulation of the vented explosion of ethylene-air mixtures. The influence of concentration, vent size, and vent burst pressure on the vented ethylene-air explosion is investigated by comparing simulation results and experiments. The different phases of external flame propagation are concluded by comparing the experimental photos and the simulation results. The external explosion process is captured by the high-speed camera and simulation. It is found that the unburned mixture expanded to the external atmosphere, which was ignited by the flame. The flow velocity, velocity vector, and turbulence kinetic energy are applied to analyze the mechanism of external flame propagation. The velocity vector is deflected to both sides of the flame front and the reverse flow velocity is captured in the external flow field. The change of ethylene concentration and the venting flow velocity is used to explain the relationship between the pressure rise, chemical reaction rate, and venting flow. Results show that the internal pressure for AV= 0.18 m2 is significantly greater than the internal pressure for AV= 0.55 m2 in this case. The smaller vent size results in higher flow velocity and turbulence kinetic energy inside of the vessel. The vent burst pressure growth promotes the acceleration of the flame front inside of the vessel. The variation curve of ethylene concentration and venting flow velocity has a similar law with different vent burst pressures. The experimental and simulated results can provide technical and theoretical support for the design of gas explosion prevention in the field of process safety and risk engineering.