Research On Combustion Characteristic Of Annular Central Bluff-body Trapped Vortex Combustor Dalian Maritime University

In order to adapt the tangential outflow of ram-totor and reduce the flow loss,the annual central bluff-body trapped vortex combustor,an important part of new concept engine,was put forward by the company of Ramgen in the United States in2007.In this paper,Fluent software is adopt to simulate two kinds of work modes of the annular central bluff-body trapped vortex combustor at combustion characteristic.(Mode 1 with fore bluff-body provide air injection and after bluff-body provide fuel injection;mode 2 with fore bluff-body provide fuel injection and after bluff-body provide air injection)The research contents include the influence that air/fuel injection on the fore-bluff and after-bluff change cause at two kinds of work modes of the annular central bluff-body trapped vortex combustor at combustion characteristic.Numerical results show that the relatively stable vortex structure can all be formed in the trapped vortex cavity under two kinds of work modes.The position of maxium wall temperature is lower wall at combustor and the after wall in the fore-bluff.There is problem between the use of different combustor height air that there is more air at higher position and less air at lower position.More air injection or less air injection can lead the work ability of combustor down with same fuel provided.In the mode that the air injection on the fore-bluff body,fuel injection on the after-bluff body,there is best work point at 100m/s velocity at after-bluff body injection 125m/s velocity at fore-bluff body injection with combustion effection71.05%,total pressure loss 4.294%,mass fraction of NOx at outlet 0.32%,OTDF0.48997.In the mode that the fuel injection on the fore-bluff body,air injection on the after-bluff body,there is best work point at 125m/s velocity at after-bluff body injection 100m/s velocity at fore-bluff body injection with combustion effection84.9%,total pressure loss 3.23%,mass fraction of NOx at outlet 0.39%,OTDF 0.597.As to the mix of air and fuel and use of the combustor structure,the mode 2 isbetter than mode 1.