Numerical study on the evolution of two-phase flow and pressure response of boiling liquid expanding vapor explosion

Abstract

This paper presents a numerical investigation of evolution of gas-liquid two-phase flow and temperature distribution during the initial stage of the Boiling Liquid Expanding Vapor Explosion (BLEVE). Motivated by the need to prevent catastrophic industrial accidents caused by BLEVE’s rapid pressure transients and thermal shocks, this study focuses on the critical milliseconds after vessel failure through the VOF computational fluid dynamics model. The results indicate that following the vessel failure, the initial temperature distribution demonstrated the characteristic of a lower temperature at the initial two-phase interface. The low-temperature region gradually enlarged as the two-phase flow developed and expanded rapidly. At the same time, a “liquid hammer” effect formed, impacting the top wall of the vessel, which caused a significant pressure rebound. Moreover, this paper studied the effect of the initial pressure, the filling rate and the opening diameter separately on the typical parameters of pressure response, such as the stagnation time, the pressure recovery ratio and so on. The results indicate that the pressure recovery ratio increased with the increasing of initial pressure, and as the filling rate rose, the pressure recovery ratio initially increased, then stabilized, and subsequently increased again. Additionally, the pressure recovery ratio decreased with the increasing opening diameter. This study provides some basic references for accident prevention of BLEVE and industrial safety design.