Influence Of The Geometrical Parameters Of Mixing Holes On The Exit Characteristics Of The Combustor

For central classification high temperature combustion chamber,combustion efficiency,outlet section pressure,outlet temperature distribution and NO generation and emission are important performance parameters to determine its combustion performance.Aiming at these parameters,a simplified combustion chamber model with three stages of cyclone is established.The influence of geometric parameters of mixing holes on the outlet characteristics of combustion chamber is studied from 4 aspects,including the shape,location,arrangement mode and pitch of holes.In the shape of mixing holes,three schemes are designed for circular,raindrop and slit,their mixing area is the same;Three schemes are designed for the position of mixing holes,the distance between them and the cyclone is0.180 m,0.195 m,0.215m;Two schemes of double row and double row are designed in the arrangement of mixing holes;Based on the scheme of double row and double row displacement,four schemes with the different spacing and the same total mixing area are designed.According to the above several design schemes,a simplified model of the combustion chamber,after simulation,compare its performance from the four aspects of each section of the combustion chamber temperature distribution,combustion velocity field,the emission of NO,the size of the recirculation region,thus comparative analysis of effects of bulk blending hole geometry parameters on the characteristics of combustion chamber outlet.It is found that the raindrop shaped mixing hole has a good regulation effect on the outlet temperature distribution of the combustion chamber.The circular mixing hole has a positive effect on limiting the NO emission of the combustor outlet;Within a certain range,with the increase of the mixing hole distance,the temperature of the main combustion zone will gradually increase,the NO emissions will increase gradually,the RTDF of the combustion chamber outlet will increase,the OTDF will decrease,the shape of the recirculation zone will gradually lengthen,and the combustion stability will be slightly affected;The performance of dual row to row mixing holes is better than that of double row rows of mixed holes in the outlet characteristics of each combustion chamber.The asymmetry of the mixing holes in the flame tube will lead to the uneven temperature distribution of the outlet,the increase of the outlet NO generation,the smaller area of the recirculation area,and the instability of combustion;With the pitch of holes becomes larger,the number of mixing holes is reduced,the mixing area of each mixing hole is larger,the distribution of temperature distribution in the combustion chamber is poor,and the temperature decreases,the RTDF and OTDF become smaller,the shape of the reflux region becomes worse,and the stability of the flame is affected.