加温加压条件下复杂旋流液雾火焰流场测量

In order to study the flow field characteristics of centrally staged combustor， optical diagnostics under inlet pressure of up to 1 MPa and inlet temperature up to 700 K， were carried out by using particle image velocimetry (PIV)， kerosene planar laser induced fluorescence (PLIF)， and CH* chemiluminescence. To tackle the technical challenges encountered in PIV measurements of the highly luminescent spray flames，multiple aspects in the experiments were carefully optimized，including particle seeding， operation procedure， optical path layout， imaging filtering， and image pre-processing. Under constant inlet temperature，pressure，and fuel flow rate，with the increase of air flow rate，the following phenomena were observed from the optical data: coupling between the main and pilot flows was enhanced；the core of the primary recirculation zone (PRZ) moved upstream and away from the centerline；the lip recirculation zone (LRZ) was shortened； decrease in the local equivalent ratio of the pilot stage resulted in more stoichiometric reactions，and the overall heat release was enhanced，with the flame centroid moving away from the combustor centerline.