A burning velocity correlation for premixed hydrogen/air/steam flames

In view of safety assessment of containment integrity in nuclear power plan ts, the structures and burning velocity characteristics of hydrogen/air/ste am premixed flames have been analyzed numerically using a detailed chemical mechanism with 19 elementary steps concerning H-2/O-2 reactions. Time inte gration and the modified Newton method are applied in solving the governing equations and an adaptive grid method is employed to resolve the stiffness . Burning velocities are obtained as a function of hydrogen mole fraction, st eam mole fraction, and initial temperature. The effect of carbon monoxide a ddition on burning velocities are also considered. The calculated burning v elocities are generally lower than the existing experimental values. Howeve r, they show good qualitative agreement irrespective of the reaction mechan isms used in the computation. Steam is found to have both cooling effect an d chemical effect affecting chain-branching reaction and heat release. A co rrelation on burning velocities is obtained and can be used as an improved relation over a wide range of steam concentration.