Experimental and numerical investigation of ignition effects on explosion temperature fields in residential buildings

Abstract

This study systematically investigates the temperature evolution characteristics of methane explosions in a full-scale residential building under various ignition scenarios through a combined approach of full-scale experiments and CFD simulations. A 280 m 3 full-scale experimental platform was constructed to accurately replicate the layout of a typical Chinese residence. Based on the stratified concentration field formed during a multi-stage leakage process, the effects of six horizontal ignition locations (kitchen, dining room, living room, master bedroom, second bedroom, bathroom) and three ignition heights (2.0 m, 2.3 m, 2.6 m) on the temperature response were examined. The key findings are as follows: (1) Methane buoyancy induces significant vertical thermal stratification, with explosion energy predominantly concentrated in the upper region; (2) Ignition timing dominance (earliness of ignition plus flame residence time) surpasses local concentration dominance—although the master bedroom has the lowest methane concentration throughout the residence, when serving as the ignition source, its peak temperatures exceed those in other rooms by more than 20%; (3) Ignition height and horizontal location systematically regulate temperature responses: increasing ignition height from 2.0 m to 2.6 m enhances peak temperatures in distal rooms by 6.1-29.1% (average 14.6%) and advances peak arrival times by 6.2-8.8% (average 7.1%), while horizontal ignition location determines flame propagation sequences through building connectivity. Furthermore, confined small spaces (master bedroom, second bedroom, bathroom) prolong flame residence time, generating localized high-temperature regions exceeding 1300 K. Narrow passages (foyer, internal doorways) induce flame acceleration through jet formation and enhanced turbulent mixing. The kitchen glass partition acts as a transient “selective barrier”, significantly altering flame morphology and venting paths. The findings demonstrate that the distribution and propagation of flame temperatures are governed primarily by ignition location and building layout, rather than by fuel concentration alone. The leakage-explosion chain model established in this study provides a scientific foundation for explosion risk assessment and mitigation design in residential buildings.