Study of flow pattern transition of jet impingement on a non-flat rotating wall
The spinning disk reactor,which uses jet to impact the rotating wall to form a high gravity and high shear film flow,is widely used in the fields of material preparation,polymerization and so on.Considering the effects of flow rate,rotational speed and viscosity of experimental materials,the effects of different groove structures on the surface of the reactor on the characteristics and transition rules of the liquid film flow pattern were studied by using the visualization platform.The flow pattern transition phase diagram was drawn and the transition conditions of the spiral broken wave were defined.The results showed that the distribution range of spiral wave in radial grooved disks was the largest among all types of disks,and the larger the number,the larger the flow range of maintaining spiral wave.With the increase of the number of circumferential grooves,the initial formation speed of spiral broken wave decreased,while the radial grooves always maintained a low speed.With the increase of the number of grooves,the operating flow range of spiral broken wave increased significantly,especially in radial grooves.The maximum Rej value of the spiral broken wave on the radial groove disk can reach 17 486,exceeding the upper limit of 12 823 on the circumferential groove disk,and the corresponding α value was 444.5 and 815,respectively,which indicated that the flow range of the spiral broken wave on the radial groove disk was wider and the centrifugal force required for spiral wave breakage was lower.When the viscosity of the experimental medium increased,the critical transition speed of the disk structure was higher than that of the disk in the lower Rej range,and the speed required for full spreading was higher.When the experimental medium was 50wt％glycerol,the Rej value of spiral broken wave maintained on smooth disk was less than 1318,indicating that the existence range of spiral broken wave was narrower than that of other structures.In the higher Rej range,the influence of groove type and distribution on flow pattern transformation was weakened,and the effect of radial groove was better than that of circumferential groove.This study provided a theoretical and applied basis for improving the micro-mixing and reaction performance of rotary reactor by regulating the liquid film flow behavior with non-flat surface.
fluid mechanicsflow patterndisk structurespinning disk reactor
NETL
NSTL
万方数据
