Mixing Laws and Chemical Reaction Mechanisms for Predicting the LBV of CH4/CSC Gases Premixed Flame

Abstract

Coal spontaneous combustion (CSC) process releases a large number of combustible gases, which bring threat to the combustion and explosion of mine methane (CH₄). Under the action of CSC, the combustion characteristics of CH₄ will undergo significant changes. In the current work, the laminar burning velocity (LBV) of CH₄/CSC gases mixed flame was obtained in a constant volume chamber (CVC) under an initial pressure of 0.1 MPa and an initial temperature of 300 K over a wide equivalence ratio range of 0.7–1.3 with three kinds of CSC gases mixing ratios. The effects of CSC gases addition on the LBV of CH₄ were analyzed first. And then, four kinds of mixing laws were used to predict the LBV of CH₄/CSC gases mixed flame. In addition, six kinds of detailed reaction mechanisms were used to calculate the LBV of CH₄/CSC gases mixed flame. Results show that the mixing of all kinds of CSC gases increases the LBV of CH₄, and T mixing law is more suitable for predicting the LBV of CH₄ mixed with CSC gases in the second stage, while the modified and simplified USC 2.0 mechanism can predict the LBV of CH₄ mixed with CSC gases well in all three stages.