Investigation of the non-uniform fuel distribution effect on a full annular rql combustion chamber outlet temperature profile using large eddy simulation

One of the most important requirements in the design and development of an aero engine combustion chamber is to achieve uniform temperature pattern in circumferential direction and a radial temperature profile in traverse direction with a peak in the middle. Outlet temperature distribution and outlet temperature profile is mainly affected by mixing of air and fuel, number and size of the cooling and dilution holes and the distribution of the fuel on fuel nozzles. Nowadays, these kind of valuable and critical parameters are predicted using reactive Computational Fluid Dynamic (CFD) analysis. In the present work, a full annular reverse flow RQL (Rich burn quick Quench Lean burn) type combustion chamber that belongs to 160-180 kW turboprop/turboshaft engine using in 2-5 people capacity small aircraft have been investigated using LES (Large Eddy Simulation) under European Commision Seventh Framework Programme (FP7) ESPOSA (Efficient Systems and Propulsion for Small Aircraft) project. In order to observe the effects of uniform and non-uniform fuel distribution on combusion chamber outlet temperature profile, reactive CFD computations have been performed. Additionally, CFD results have been compared. with experimental data obtained by CIAM (Central Institute for Aviation Motors). Before the full annular geometry calculations, RANS (Reynolds Averaged Navier Sokes) computations have been performed with 30 degree sector geometry which corresponds to one injector. Thus, preliminary studies have been comleted and the suitable models and mesh resolution have been obtained. In order to obtain mesh independent solution, several analysis have been performed with three different computational grid which are 1.8 million, 7.5 million and 29 million. According to the mesh, turbulance model and combustion model studies, Relizable k-ε turbulance, SLF (Steady Laminer Flamelet) combustion model and medium mesh have been selected as suitable sub-models for further analysis. In addition to sector calculations, full annular geometry calculations have been copleted with RANS and LES methods for uniform and non-uniform fuel distribution situations. Furthermore, outlet temperature fields and temperature profiles have been compared with experimental data for uniform and non-uniform fuel distribution conditions. And finally, effects of the fuel distributions on combustion chamber outlet temperature profiles have been investigated. Also outlet temperature profile, radial temperature distribution factor (RTDF) and overall temperature distribution factor (OTDF) are calculated.