Numerical Study of Flame Propagation Morphology for Deflagration in the Pipeline Using Proper Orthogonal Decomposition

摘要

A multilevel independent spatial modal analysis of flame propagation characteristics of a deflagration in a specific pipeline was performed using the proper orthogonal decomposition (POD) method, in order to research the evolution process of the explosion which is closely related to flame propagation speed and front rupture pressure. The CFD results indicated that the full-order calculation results well agreed with the normal combustion propagation characteristics of premixed methane-air for the flame propagation with the unbroken thin layer. The POD analysis results showed that the static temperature gradient of the 1st order mode of initial and subsequent stages both exhibited a range of continuity change from left to right, and the frontal curvature of the cooling area decreased as the flame propagated in all stages. The number of the low-temperature interval regions displayed an expanding form of a staircase with the increase of the mode order, especially for subsequent flame in which the interval areas became more and more slender. Moreover, the level of information content in the multilevel modal space was mostly concentrated in the first 3 modes, especially in the 1st order mode, and the flame propagation pattern at the initial stage was more complicated than the subsequent based on the relational information content features.