Numerical Prediction of Diluted Hydrogen Turbulent Jet Diffusion Flame Using a Scalar Probability Density Function Method Considering Detailed Chemical Kinetics

Abstract

A scalar probability density function (PDF) approach considering a detailed chemical kinetics is applied to a diluted hydrogen jet diffusion flame to evaluate the performance. The flame is formed on the nozzle of an inner diameter of 6 mm, with a fuel exit velocity of 30 m/s, surrounded by two annular pipes issuing airs of higher and lower velocities of 30 m/s and 3 m/s, respectively. The flow field has been solved on the basis of the k-ε two equation model. The modeled PDF transport equation has been solved by an Eulerian Monte-Carlo method. The results are compared with those of two flamelet calculations, which are based on the conventional laminar flamelet model method and a scalar PDF method based on the conserved scalar approach. The present PDF method predicts the maximum temperature on the center axis close to the experimental one than the other methods. The temperature downstream of the maximum temperature position has however been overestimated due to the underestimate of the mixing. The present PDF method has reproduced the extinction and reignition phenomena, which cannot be easily predicted by the conventional flamelet calculation. The variation in the diffusion flame structure due to the flame stretch, which was experimentally confirmed by Barlow et al., has been also reproduced. Moreover, the PDF calculation has revealed that intermediate radical species are created largely under the flame stretch effect.