Nonpremixed flames in stagnating turbulence part I— The k ̅-ε ̃theory with equilibrium chemistry for the methane-air system

Non premixed turbulent flames in opposed air and methane streams are analyzed on the basis of the k ̅-ε ̃ theory under conditions of chemical equilibrium. The methane-air system is chosen to permit comparison with existing experimental data. It is found that the thickness of the experimentally observed flames is so large as to prelude application of the current thin flame analyses. Accordingly, the usual thin flame approach is avoided and solutions for the entire flow from the exit plane of one jet to that of the other are obtained. Difficulties are encountered in comparing theory and experiment as a consequence of the flow conditions and the instrumentation used to collect the data. Nevertheless it is considered worthwhile to attempt this comparison; indeed some aerothermochemical quantities are satisfactorily predicted. We examine the influence of several aerothermochemical quantities on the character of these flames.