Analysis Of Combustion Flow In Trapped Vortex Combustor With Turbulator

As a new combustion device with stable flame and low pollution performance,trapped vortex combustor?TVC?has attracted more and more attention at home and abroad.The trapped vortex combustor with turbulator?including guide vanes,inclined structs and blunt body?is a new combustor structure proposed on the basis of previous ones,which is beneficial to realize efficient and stable combustion in TVC.In this paper,combustion flow characteristics of the TVC with turbulator are numerically simulated and the structure of the turbulator is optimized.The results show that the TVC with turbulator can form two groups of stable double-vortex structure in the cavity,which is beneficial to stable combustion and gas mixing.Compared with the situation of the TVC only with blunt body,it can greatly improve the combustion efficiency of the combustor and the outlet temperature distribution,and reduce NO emission.When only the guide vanes and inclined structs are arranged,the combustion efficiency of the TVC with turbulator can reach more than 99%.When the blunt body is arranged,the backflow area can be formed behind the blunt body to increase the distribution range of the high-temperature area and improve the outlet temperature distribution.The optimal structure parameters of the TVC with turbulator are?=30°,BR=12%²4%,a/B=0.1⁰.4,b/h=0.4,c/L=0.2,H₁/B₁=2/3.In order to study the influence of different working conditions?the gas equivalent ratio,inlet velocity and inlet temperatureand?and blunt body shape on the TVC with turbulator,the performance of the combustion flow is analyzed on the basis of the obtained optimal structure.The results show that with the increase of the equivalent ratio,the range of the low-speed backflow zone behind the blunt body decreases gradually,and the lean combustion condition is more favorable for combustion.As the inlet velocity increased,the total pressure loss increases significantly,up to17.5%,and the combustion efficiency changes little,all above 99.6%.As the inlet temperature increased,the length of the low-speed backflow zone behind the blunt body significantly increases,and the total pressure loss gradually decreases.The combustion efficiency increases gradually,all above 99.75%;The production of NO increases dramatically.The shape of blunt body has great influence on the reflux area in the cavity and behind the blunt body,and combustion efficiency have little influence.The total pressure of circular arc blunt body is the lowest,and NO emission of rectangular blunt body is the lowest.In order to conduct a study on the wall cooling of combustor,gas cooling grooves are opened on the wall of combustor,and the influence of different blow ratio R and cooling air incidence angle?on cooling effect is analyzed.The results show that when incidence angles?=60°,the cooling effect is best;Increasing the blowing ratio R can improve the wall cooling efficiency and combustion efficiency of the combustor,but when the incidence angles are different,the impact on the total pressure loss is different.To investigate the flow heat transfer performance of the TVC with turbulator,the field synergy angle between velocity field and temperature field is analyzed.The results show that there is good field synergy between the trapped vortex region and the low-velocity reflux region,which is beneficial to heat transfer enhancement.The field synergy performance of the TVC with turbulator is the best at the central section?Z=0m?of TVC.The average synergy angle of the volume is larger than the average synergy angle of the central section?Z=0m?.The equivalent ratio and the incoming velocity increase,the flow resistance increases,and the heat transfer performance weakens.When the inlet temperature increases,the heat transfer performance remains basically unchanged.