Study Of The Characteristics Of The Flow And Flame In Low Swirl Combustor

Low swirl combustion technology(LSC)is a new combustion technology that can realize low pollutant emission.It can eliminate strong center recirculation region,through increasing direct center flow in the traditional swirl injector,achieving the goal of reducing pollutant emission.Low swirl injector(LSI)has been widely concerned on account of its simple structure and low pollutant emission characteristics.Therefore,it has important practical significance to study the characteristics of the flow and combustion in low swirl combustion chamber.In this article,the different swirl injector has been simulated using FLUENT,by means of computational fluid dynamics.The characteristics of low swirl flow and flame have been studied,through investigating the flow field and flame temperature distribution,the axial velocity distribution,the distribution of CO and OH and the production formation rate distribution.Results show that with the increasing of swirl number,the flame front,center recirculation zone and the position of the minimum centerline velocity move upstream;the vortex structure isosurface after Q criterion processing and vortex strength decrease;But the distribution of the main combustion intermediates CO and OH concentration remain unchanged.The low swirl flame has a good self-similarity。The flame front position is not affected by equivalent ratio and composition of fuel,the flame of different equivalent ratio and fuel lift to a constant position,the flame height and width basically remain unchanged.Finally,the single cylinder low swirl combustor has been designed and the designed condition simulation has been carried out on the full size.It has been found that the combustion chamber can form low speed at large area to stabilize flame,combustion chamber can form good cooling air film near the wall,through the cold flow field analysis;Through investigating the flame shape,temperature distribution,component distribution and pollutant emission in low swirl combustor,low swirl combustor can form a typical "W" shape low vortex flame;Outlet temperature、the maximum non-uniform degree and uneven coefficient meet the design requirements;The combustion efficiency gets higher with the increasing of swirl number;Low swirl combustion chamber emissions are lower significantly than the high swirl,and get higher with the increasing of the swirl number.