Numerical Study On The Propagation And Quenching Of Premixed Flame In Tubule

The characteristic of propagation and quenching of flame in micro channel is one of important security technologies. To develop the study on the propagation of flame in micro channel, the quenching characteristics of premixed flame in tubules have been systemically investigated by numerical simulation.Based on the time-averaged equations of homogenous reaction flow, k - e turbulent model and EBU-Arrhenius combustion model, the theoretical model of homogenous turbulent combustion flow has been formed. The two-dimensional numerical simulations of the process of propagation and quenching of premixed flame in tubules have been carried out by the general CFD code FLUENT with SIMPLEC scheme.The process of propagation of propane-air premixed flame in 60M multi-layer wire-web has been simulated firstly, and numerical values are in good agreement with corresponding experimental values. So the validity has been proved using the turbulent mathematical model to simulate the process of propagation and quenching of premixed flame in tubules.The geometrical model of tubule has been formed, and the grid size sensitivity has been performed in FLUENT.The main conclusions of this paper through the numerical simulation of the propagation and quenching of premixed flame in tubules are as follows:(1) Premixed flame in tubules exhibit three kinds of behaviors, i.e., not-passing-through, not-passing-through-with-retardation and passing-through-with-retardation. These behaviors have been described in detail by the contours of rate of reaction and temperature at different time. The heat energy of reaction not being absorbed in time is the cause of flame retardation.(2) The relationships between the flame velocities, tubule diameters, initial temperatures and the quenching lengths are obtained. The quenching length increases with the increase of velocity, diameter and initial temperature.(3) The quenching characteristics in tubules are compared among the propane-air, methane-air and acetylene-air, and the conclusion is obtained that the quenching length increases with the increase of the reaction activity.(4) Comparisons of quenching characteristics between tubules and narrow channels are obtained. And tubules' quenching characteristics are better in the same conditions.(5) Based on analyzing a large number of simulations, the experiential formula about the relationships between flame velocities, tubule diameters, initial temperatures and quenching lengths is obtained, and is in good agreement with numerical values.c D-0.2 K + 50 Tini+TaSo this experiential formula is applicable to describe the quenching characteristics of premixed flame in tubules.