Laser Diagnosis Method And Characteristic Analysis Of Swirl Combustor

Combustion is a complex chemical reaction phenomenon with the interaction of flow field,flame and heat release.The measurement of three-dimensional velocity of convection field is helpful to study the combustion mechanism and combustion dynamics.On the basis of sufficient literature research,the lean premixed swirl combustion experimental platform is designed and completed.Based on the tomo PIV test technology,the three-dimensional velocity measurement of the swirl combustor is carried out.The reconstruction quality of the experimental flow field and the accuracy of the three-dimensional velocity vector field are evaluated The three-dimensional flow field characteristics of swirl combustor were analyzed in detail.The main work and achievements of this paper are as follows:(1)Based on tomo PIV test technology,the lean premixed swirl combustion experimental platform was established,which mainly includes the construction of camera system and the arrangement of laser lighting system light path.In addition,it also includes the construction and connection of combustion chamber system,tracer particle generator,pipeline system and OH * flame spontaneous light system.(2)The reconstruction quality factor and signal-to-noise ratio are used to quantify the accuracy of the reconstructed flow field of the three-dimensional velocity measurement experimental platform.The reconstruction quality factors of the experimental parameters in this paper are all greater than 0.75,and the signal-to-noise ratio of the experimental results is 2.57.Both parameters show that the fluid reconstruction quality of the experimental system is good.At the same time,the velocity vector field measured by tomo PIV technology and 2D-PIV measurement technology under the same conditions was compared,which proved the effectiveness of the three-dimensional velocity vector field measured by the experiment.(3)Based on the space laser diagnostic platform of swirling combustor,the cold state experiments with different swirl numbers and the hot experiments with different equivalence ratios were carried out.The measurement and visualization of 3D velocity field in swirl combustor were realized.The results show that the flow field in the swirl combustor is spirally rising.With the increase of swirl number,the axial reverse velocity in the central recirculation zone becomes larger,and the larger axial reverse velocity can absorb more high-temperature products as the continuous ignition source of the premixed gas entering the combustion chamber,so that the flame can stably burn at a lower equivalence ratio;compared with the cold and hot flow field,the shear of hot flow field is higher The higher axial velocity is beneficial to the exchange of material and energy between combustion products and unreacted parts,and promotes the combustion reaction.This paper provides a reference value for the study of complex combustion mechanism and new combustion chamber design,and lays a foundation for further research on three-dimensional swirling combustion.