This paper describes the methodology and application of Computational Fluid Dynamics (CFD) to Dry Low NOx (DLN) combustion systems throughout the range of small industrial gas turbines produced at European Gas Turbines (EGT) Lincoln UK.
The use of CFD in the development of such systems has been encouraged not only by the availability of a variety of general purpose CFD codes, but also by the inherent difficulties associated with direct measurement in such a harsh environment. Combusting flow analyses provide detailed predictions of local temperature and velocity fields together with exhaust emissions, enabling numerous conceptual studies to be undertaken without the usual associated mechanical difficulties.
In particular, the work EGT has concentrated on concerns the prediction of fuel / air mixing quality upstream of the flame front, in order to assess the effect of fuel injector design variables on NOx production. This methodology has accelerated injector development resulting in less than 10 ppmV NOx combustors.
Validation of the detailed features of the flow field is currently underway, though parametric comparisons have already proved consistently accurate in displaying the trends necessary for the development of an ultra low NOx combustion system. Correlations of rig emissions data with overall predictions have shown to be in good agreement.
