Prediction of NO_x Emissions from High-temperature Gas Turbines : Numerical Simulation for Low-NO_x Combustion

In recent years, turbine inlet temperatures in gas turbine systems have continued to rise in order to enhance efficiency and performance. However, higher temperatures results in increased levels of NO_x emission and this in turn seriously affect the environment. Development of prediction methods for NO_x emissions is important, since this allows one to evaluate the environmental contributions of gas turbine systems. The gas turbine combustor geometries are very complex so that the flow pattern, chemical and thermal field inside the combustor is very complex. Numerical methods for predicting the performance of the combustor and NO_x formation and emission levels are attractive as they provide inexpensive solutions to the complex geometry problem without physically building the hardware. This paper provides numerical simulations for predicting the NO_x emissions from gas turbine systems using : (i) chemical equilibrium and simplified kinetic reaction approaches, and (ii) flamelet and reaction progress variable approaches.