Study Of Vortex-nozzle Interactions With Condensation

Vortex and condensation are common physical phenomena in daily life and indus-trial production,and have received widespread attention and in-depth research.Under certain conditions,such as various types of nozzles,these phenomena affect each oth-er,create complex interaction processes,and even change the working conditions of the relevant equipment.In this paper,the ASCE2D program developed based on the VAS2D program is used to numerically study the vortex flow in the nozzle and its inter-action with condensation.By designing the grid refinement method following the vortex movement,the detailed capture of the details of the vortex evolution can be achieved.First of all,a numerical model consisting of Taylor vortex and Ludwieg tube is established for the interaction between the nozzle and the vortex,and the complete pro-cess of the vortex through the nozzle is simulated.The flow parameters(nozzle axis pressure,wave system structure,etc.)in the nozzle and vortex characteristic param-eters(vortex shape,vortex center trajectory,vortex center migration velocity,vortex area,etc.)evolved over time are investigated under different vortex intensities.The re-sults show that the vortex in the front of the nozzle has obvious pressure disturbance;the vortex expands outwards in the expansion zone before and after the throat,the area increases but the total circulation remains basically unchanged,and the pressure distur-bance gradually decreases.When the vortex is strong,shock waves are generated at the upper and lower positions inside the vortex and interrupted at the vortex core.When the anticlockwise vortex approached the throat,the orbit of the vortex begins to deflect toward the upper wall,and the migration speed is suppressed;the stronger the vortex,the more obvious the trajectory elevation and the smaller the migration speed.Then,the vortex interactions with the nozzle in the presence of water vapor con-densation is studied.By increasing the total temperature of the chamber,the separation of the vortex condensation and the mainstream condensation in time and space is real-ized,the self-excited oscillation of the main condensation of the nozzle is suppressed,and the interaction between the vortex condensation and the nozzle can be more clearly analyzed.The results show that the condensation in the vortex will occur due to the decrease of temperature,and the latent heat released by the condensation causes the lo-cal temperature to rise.The competition between them forms a phenomenon in which the temperature,density,liquid water mass,and other parameters fluctuate periodically from the center of the vortex.Due to the temperature inside the strong vortex is lower than the weak vortex,the position where the strong vortex condenses in the nozzle is in the front of the position where the weak vortex condenses.At the outlet of the nozzle,the average radius of droplets generated by the strong vortex is smaller than that of the weak vortex,and the number of droplets is larger than that of the weak vortex.The rate of condensation in the vortex and the rate of droplet growth fluctuate due to the effects of both water vapor consumption and cooling following the mainstream.Condensation will cause the vorticity to concentrate toward the vortex center and reduce the vortex area.The vortex nucleation first increased and then decreased when the vortex was transported in the nozzle,and then increased again.