The Numerical Study On Combustion Emissions For Gas Turbine Combustor

With the gradual awareness of environmental protection, the pollutant emissions from fuel combustion have been paid more and more attention. The high efficient and low emissions combustor is a manifestation of an advanced engine. Therefore, the way to control NOx emission and improve combustion efficiency is the key of gas turbine design. This study shows the development and application of Chemical Reactor Networks (CRN) for different gas turbine combustion systems. Based on the analysis of the computational fluid dynamics (CFD) results, CRN is set up with detailed gas-phase chemical kinetic mechanism. In the research, the trends of nitrogen oxides (NOx) and carbon monoxide (CO) varying with the equivalence ratio are conducted. Effects of the inlet temperature and pressure on NOx and CO emissions are also presented. At last, the numerical results are compared with the experimental results.For the 100kW can-type micro gas turbine, the total amount of air is divided to primary air, secondary air, mixing air and ignition air flow by the hole area ratio. Two different CRN models are built to simulate the combustion chamber. One is relatively simple, another is more complex. Compared the emissions simulated by the two models with the experimental results respectively, the complex network is better description of experimental results. Using CRN2, the trends of NOx and CO varying with equivalence ratio, inlet temperature and pressure are conducted. The flow coefficient plays an important part in the air distribution of combustion chamber. Therefore, CRN3 is established. The network mainly focuses on the various of CO and NOx in every chemical reactor, especially the polit fuel and main fuel reactors.For the annular combustion chamber, numerical simulation is completed for the annular combustor with 3D CFD methods. According to the CFD analysis, especially the flow field, temperature field and boundary conditions, a chemical reactor network has been applied. Using the detailed chemical kinetic mechanism, the pollution emissions and temperature distribution are calculated. The trends of NOx and CO varying with the inlet temperature, pressure, residence time and the role of flow return are also evaluated.