Experimental Investigation Of The Characteristics Of Particle Behavior In Impinging Streams

Two-phase opposed jets has an important applications in industry.The structure of turbulent impinging streams is very complex,the former studies focus on single-phase flow,however the quantificationally experimental investigation about particle-phase in opposed jets and turbulence modifications are very few.Particle behavior characteristics of two-phase opposed jets are experimentally investigated by using PIV/PTV measuring system.The impinging streams are designed with Reynolds,10000、14500,and nozzle spacing L/d=5、12、20.Particle phase use glass beads which diameter is 100、200μm,and mass loading ratios are designed to range from 1% to 4% respectively.The original images are separated to gas phase and particle phase images,then use PTV algorithm to particle phase,to get the position information of particles.Then we can get statics of particles,for instance particle concentration,axial average velocity,fluctuation velocity.We analyse the statistical regular under three nozzle spacing.In this experiment,we don’t have to consider particle collision.The greater the nozzle spacing,more obvious gravity acts on particles,particles can penetrate the reverse jet with greater speed,and the greater the high turbulent mixing zone.We also analyse the turbulence modifications after adding particles.The axial and radial average velocity is significantly reduced.The maximum axial average speed occurs by the nozzle exit to the downstream of the nozzle.When nozzle spacing is long enough,turbulence kinetic energy in the axial jet is significantly increased,but it is slightly reduced and it suppresses the gas phase’s transfer in the impinging zone.When nozzle spacing is small, the turbulent kinetic energy is increased.The particle phase also changes axial jet structures remarkably.The changes of axial jet are different with the different nozzle spacing.