SHI F C, WANG X, PEI B. Effects of constraints on explosion characteristics of biogas/air premixed gas in duct [J]. Journal of Henan Polytechnic University (Natural Science), doi:10.16186/j.cnki.1673-9787.2025060049.

Received：2025-06-30

Revised：2025-11-14

Online：2025-12-04

Effects of constraints on explosion characteristics of biogas/air premixed gas in duct (Online)

Shi Fengchao¹, Wang Xi¹, Pei Bei^1,2

(1. School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo 454000，Henan，China；2. State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization，Jiaozuo 454000，Henan，China)

Abstract: Objectives With the increasing application of renewable energy biogas, its combustion and explosion hazards have drawn significant attention. This study is intended to deeply investigate the influence of constraint conditions on the explosion characteristics of biogas with different compositions, clarify the variation laws of flame propagation and pressure evolution after deflagration, and promote the safe utilization of biogas. Methods Aiming at the typical pipeline scenario with a large length-diameter ratio in biogas storage and transportation, experimental investigations were carried out in a self-constructed pipeline with a large length-diameter ratio. The pipeline was sealed with PVC films of varying layers at the left end (film thickness increasing linearly with layers) and closed at the right end, enabling systematic analysis of explosion parameters by regulating the film layers and methane concentration in the mixture. Results The number of PVC film layers exerts a more significant influence on the overpressure peak of premixed gas than CH₄ content. As the layers increase from 1 to 9, the pressure waveform transitions from bimodal to unimodal with 3 layers as the critical threshold. Increasing film layers enhances the maximum pressure growth rate more effectively than elevating methane concentration. CH₄ content in biogas dominates the influence on flame propagation time and front velocity. At a fixed number of film layers, the maximum instantaneous flame velocity increases linearly with CH₄ content, while the propagation time decreases accordingly. The dynamic changes in flame front velocity, position, and pressure during premixed gas explosion are strongly correlated with the turbulent evolution of flame structure. Conclusions This study clarifies the regulatory laws of constraint strength and biogas components on explosion characteristics, and it provides critical theoretical foundations and technical references for safety design of biogas storage/transportation facilities, optimization of deflagration venting devices, and risk prevention in engineering applications.

Key words：biogas; explosion characteristic; tulip flame; constraint condition; overpressure

CLC: TD712.7