Numerical simulation of the effect of diaphragm orifice diameter in a flameproof enclosure with an interconnected structure during pressure piling

Abstract

Combustible gas explosions are typically triggered at high temperatures by the generation of electric sparks on starting, stopping, or short circuiting of electrical equipment. Flameproof enclosures are widely installed in the petrochemical industry as safety equipment for eliminating ignition sources. Such enclosures are designed with a double-cavity structure, and a hole plate is used to connect the two cavities. However, pressure piling occurs in such double-cavity-connected structures, resulting in flameproof enclosures requiring to bear higher pressure than designed, which is a safety hazard. However, few studies have focused on the effect of the diaphragm orifice diameter of flameproof enclosures. Because the explosion of combustible gas in a flameproof enclosure is a complex process, numerical simulation was performed to study the process. Fluent was used for numerically simulating the ethylene/air premixed gas explosion characteristics of double-cavity-connected structure flameproof enclosures. The effects of an orifice hole diameter from 10 to 45 mm on flameproof characteristics, including the maximum explosion pressure, maximum explosion pressure rise rate, and maximum explosion index, were examined. The results are critical for the effective design of a double-cavity flameproof shell and provide theoretical support for fire suppression in a flameproof enclosure.