Numerical study of external explosion characteristics induced by indoor natural gas vented explosion

Purpose The purpose of this paper is to ascertain the harm to personnel and equipment caused by an external explosion during natural gas explosion venting. The external explosion characteristics induced by the indoor natural gas explosion are the focal points of the investigation. Design/methodology/approach Computational fluid dynamics technology was used to investigate the large-scale explosion venting process of natural gas in a 6 × 3 × 2.5 m room, and the characteristics of external explosion under different scaled vent size (Kv = Av/V2/3, 0.05, 0.08, 0.13, 0.18) were numerically analyzed. Findings When Kv = 0.08, the length and duration of the explosion fireball are 13.39 and 450 ms, respectively, which significantly expands the degree and range of high-temperature hazards. The suitable flow-field structure causes the external explosion overpressure to be more than twice that indoors, i.e. the natural gas explosion venting overpressure may be considerably more hazardous in an outdoor environment than inside a room. A specific range for the Kv can promote the superposition of outdoor rupture waves and explosion shock waves, thereby creating a new overpressure hazard. Originality/value Little attention has been devoted to investigating systematically the external explosion hazards. Based on the numerical simulation and the analysis, the external explosion characteristics induced by the indoor large-scale gas explosion were obtained. The research results are theoretically significant for mitigating the effects of external gas explosions on personnel and equipment.

CREATION OF MATHEMATICAL AND COMPUTER MODELS OF THE DYNAMICS OF FLAME PROPAGATION OF AIR-SUSPENDED SOLIDS IN VARIOUS ROCKS USING MATLAB ENVIRONMENT

The propagation of transient, air-suspended solids in a vented explosion chamber is numerically investigated by a dynamic formulation for the Concentration Limit of Flame Propagation (CLFP) with the GUI MATLAB environment. The geomechanics is modeled by a one-step overall reaction, which simulates the reaction of a stoichiometric propane– air-suspended solids. The CLFP modeling in the reaction rate model is numerically employed with mathematical models on basis Antoine's equation. This is based on an empirical correlation of the velocity fluctuations and implemented as interface with input-output data with graphic realization. The computer modeling show that the dynamic CLFP models provide superior results as general implementation of physical process of flame propagation and could be used for different rocks (f.e. granite, limestone, sandstone etc).