Investigation Of The Combustion Performance In A Model Combustor With Single Dome

In order to understand the combustion performance of the aeroengine annular combustor,a model combustor with a single dome and two-stage axial swirler was chosen to be the study subject in this thesis.And both experimental and numerical methods were applied to understand the flow field and the combustion performance of the model combustor.First,the PIV technique was used to measure the non-reacting and reacting flow fields of the model combustor,and analysis was carried out to assess the influence of the inlet parameters on the flow field in the combustion chamber.Second,the samples of the exhaust gas on the combustion chamber’s outlet plane was taken to study the pollution emission and the variation of emission to different inlet parameters.Finally,numerical simulation of the model combustor was considered and compared with measured data,to evaluate the turbulence models and combustion models using commercial software Fluent.The conclusions are as following:1)In the none-reacting flow field,with the increase of the inlet flow rate,the axial and radial velocities at the center line of the chamber increase and the length of the recirculation zone slightly increases as well.However downstream of the swirler outlet,the height of the recirculation zone narrowed;And when increasing the combustor inlet temperature,the axial velocity has increased and the stagnation point of recirculation zone move forward;Compared with the cold flow field,the structure of the reacting flow field is similar to the previous one,but the width of the recirculation zone is smaller.As the fuel/air ratio increases,the recirculation zone becomes thinner and the axial velocity at the line of the chamber becomes larger.2)For the test of the combustion performance of the model combustor,along with the increasing of the fuel/air ratio,the combustion efficiency increases and the emission EI_COO and EI_NO decrease gradually.When the main spray nozzle is turned on,the combustion efficiency suddenly drop and then rise,but the emission EI_CO rise at first and then drop.At all measured condition the total pressure loss ratio is around 5-7%,almost unaffected by the fuel/air ratio.When only the total temperature increases,the emissions EI_COO and EI_UHC decrease,and the EI_NO increased,a higher combustion efficiency was achieved.The same performance variation could be attained as well when only increasing the inlet total pressure.3)The simulation results showed that the standard k-?model can give a better agreement with the test data,it is more suitable for the prediction of combustion flow fields.And compared with the fED combustion model,the EDM model predicts higher total pressure loss ratio and emission which are closer to the measured data.