Abstract:

A numerical simulation study on the characteristics of premixed flame of propane/air is carried out by software Fluent in a smooth square channel at normal pressure and temperature conditions. Both standardized k -ε turbulence model and four-step kinetic mechanisms of propane-oxidation are initiated. Flame propagation characteristics such as flame velocity,structure,surface area,position and time-of-arrival can be obtained along the channel. The main conclusions are:the flame propagation velocity first increases and then decreases.The flame velocity achieves maximum at the distance of 50 mm from the ignition point. When t = 21 ms,a typical tulip structure flame can be observed. The positive-feedback differential loop resulted fromthe preheating and compressing unburnt mixtures by the precursor shock ahead of the flame front can be considered as the mainly mechanism of flame propagation in the channel. Subsequently,the flame propagation velocity decreases under the influence of compression waves reflected from the channel terminus. In contrast with the experimental results,the obtained numerical simulation results are reasonable.

Key words: propane, flame propagation velocity, k-εturbulence model, four-step kinetic mechanisms