To investigate the characteristics of methane-air explosions in large-scale tunnels with different structures, the CFD code for gas explosion modelling of FLACS was validated and used to model the explosions in tunnelling faces, coalfaces and crosscuts, where explosions mostly occurred in coalmines. The maximum overpressures were obtained as about 150–1400 kPa but varied for places with different cross-sections. The confinement degree and combustible mixture volume compete for controlling the overpressures, the space congestion degree influences the competition. For the tunnelling faces and crosscuts with low congestions, the increase of confinement degree caused by reducing cross-sections takes the dominant effect, which makes the overpressure in 3 m × 2 m cross-section tunnels higher. However, the 6 m × 4 m coalface produces the largest overpressure as the highly congested coalface strengthens the effect of increasing the mixture volume on pressure rise. Since the pressure reflection results from space constraints, a higher confinement degree causes a greater reflection. In crosscuts with both ends closed, the delayed combustion of the unburnt rich mixture after the seal’s failure generates a high pressure than assumed. Because of containing the same volume combustible mixtures in the crosscut modelling with the same cross-section, little difference exists in the overpressure regardless of sealing conditions. The flame is more inclined to propagate towards free spaces, and the flame of a larger volume combustible mixture fills a longer tunnel more comprehensively. In straight tunnelling faces, the flame length can be calculated as the product of the equivalent side length of the cross-section and its corresponding simulated constant.

为了研究具有不同结构的大型隧道中甲烷-空气爆炸的特征，验证了FLACS气体爆炸模型的CFD代码，并将其用于模拟爆炸面主要发生在煤矿中的巷道，煤层和横切面的爆炸。获得的最大超压约为150–1400 kPa，但对于具有不同横截面的地方，压力会有所不同。限制程度和可燃混合物的体积竞争控制超压，空间拥挤程度影响竞争。对于低拥堵率的隧道工作面和断面，由减小横截面引起的约束程度的增加起主要作用，这使3 m×2 m横截面隧道的超压更高。然而，6 m×4 m的工作面产生最大的超压，因为高度拥挤的工作面增强了增加混合气量对压力上升的影响。由于压力反射是由空间限制引起的，因此较高的限制度会导致较大的反射。在两端都闭合的横切中，密封失效后未燃烧的浓混合气的延迟燃烧会产生比设想的高的压力。由于在具有相同横截面的横切模型中包含相同体积的可燃混合物，因此无论密封条件如何，超压几乎没有差异。火焰更倾向于向自由空间传播，并且较大体积的可燃混合物的火焰更全面地填充了较长的通道。在直的掘进工作面中