Venting Of Defiagrations: Dynamics Of The Process In Systems With A Duct And Receiver

Abstract

This paper describes the application of a proposed model to vented gaseous explosions in a small and large-scale equipment with venting of deflagration through exhaust duct to receiver or atmosphere. It was shown that introduction of a duct and vacuumed receiver into explosion protection system can have strong influence on dynamics of vented deflagration and increase of maximum explosion pressure. The physics of this phenomenon was studied. Coincidence between values of the main unknown parameter of the vented combustion process modelturbulization factor x from this work and results following from K.I. Shchelkin and B. Karlovits theories was obtained and c o n f i e d by cinegrams. The 3.7-4 times growth of burnout rate in the vessel due to high level turbulence combustion in the duct was determined by inverse problem method. The discovered effect of combustion intensification can be removed by increase of vent relief pressure or sprinkling of cooling agent into gas mixture flow at the beginning of a duct.

Duct-vented Propaneiair Explosions With Central And Rear Ignition

“…Similar pressure traces in the main vessel and in the relief duct have been observed for the same venting configurations on both smaller scales and larger scales [3,8,9].…”

“…In particular the sudden energy release necessary to generate the shock wave in the duct is to be linked to a secondary explosion in the initial sections of the duct [2,3,4] and is sometimes referred to in literature as burn-up. Burn-up in the duct has then to be considered a crucial phenomenon affecting the final overpressure of the vessel.…”

“…The presence of the duct, however, results in an enhancement of the explosion severity in comparison to simply vented vessels [2,3]. This can lead to an increase in maximum overpressure by a factor of ten or more [4].…”

CFD analysis of gas explosions vented through relief pipes

“…In the last two decades a number of works have addressed the issue of gas explosions vented through relief pipes [4][5][6][7][8][9]. Several phenomena were identified as affecting the increase of the overpressure with respect to simply vented vessels such as secondary explosion in the duct (burn-up), frictional drag and inertia of the gas column in the duct, acoustic and Helmholtz oscillations.…”

“…within buildings. On the other hand, the presence of a duct is likely to increase the severity of the explosion with respect to simply vented vessels [2][3][4][5].…”