Theoretical investigation and numerical modelling of gas turbine combustion chambers

Nowadays gas turbines, with simple construction, light weight, high reliability, low cost, versatile fuel operation and compatibility to clean energy resources, gained an important place in energy production area. But also, significant attention is paid to gas turbine combustion chambers to improve combustion performance of combustor and for need to reduce combustion emissions, namely NOX, SOX, CO and CO2, of great importance. In this thesis, a 2-dimensional combustion model based on computational fluid dynamics is developed considering a can-type gas turbine combustor. Combustion model is composed of two step combustion reaction mechanisms of methane, ethane, propane fuels and Eddy Dissipation flow model, standard k-ε turbulence model and P-1 radiation heat transfer model. In this study, firstly, combustor of 30 kW thermal power is modelled for combustion process analyses of methane at different equivalence ratios. NOX emission and temperature distributions in the combustor are investigated at different equivalence ratios, 0.6, 0.7, 0.8, 0.9 and 1, respectively. Then, investigation of cooling air effect and heat transfer with radiation effect in gas combustor is carried out. Besides, to investigate the effect of thermal power on combustion, output data of a 50 kW thermal power combustor is used for comparison. Later on, temperatures and NOX emission levels of gas turbines operating with several fuels, considering methane, ethane and propane, are investigated. Also, recent analytic investigations applied to gas turbines for NOX and CO emissions are considered and investigation outputs are compared with calculated numerical simulation results.