ASSESSMENT OF THE STRETCHED LAMINAR FLAMELET APPROACH FOR NONPREMIXED TURBULENT COMBUSTION

An assessment is sought of the stretched laminar flamelet approach, in particular as far as its capability to account for finite-rate chemistry effects in nonpremixed turbulent combustion is concerned. It is used here with the k - E - g turbulence model, in order to obtain a computational model which can easily be implemented on current codes. A particularly convenient form is adopted, which limits the computational overhead over nonreacting computations to a minimum. An appropriate plane is identified to check the combustion regime in the different regions of the flame. Test cases are reported which involve quantities most directly affected by finite-rate chemistry, namely mean and variance of OH, CO and NO concentration in different flames. Numerical predictions worked out with the present model are compared to experimental results and predictions by other authors. Results confirm the potentialities of the proposed approach, which in addition can be extended to include insofar neglected effects. The pros and cons of the different approaches proposed for finite-rate chemistry are also discussed.