Flame kernel growth in a rotating gas

Artikel i vetenskaplig tidskrift, 2008

The communication deals with an ignition kernel development in uniformly rotating mixture. A simple model is presented in order to predict the time evolution of the kernel length and its diameter under the assumption of ignition on the axis of rotation, which is preferred mode for rapid flame development. The analytic expressions for flame radius and length are compared with experimental results. The predicted radius growth rate is in good agreement with experimental data, whereas the length evolution rate predictions deviate substantially from measurements due to flame propagation effects involving quenching and perturbation of the surrounding flow by the growing kernel. An interesting general result supported by the theory and experiment is that the diameter growth rate of the cylindrical part of the kernel is about half the growth rate of the spherical kernel in a quiescent mixture and is independent of the rotation rate. Wall effects start to reduce the kernel development rate when the distance from the wall is less than double the kernel diameter. The effects are quite strong.