Abstract A comprehensive three-dimensional model of droplet-gas flow was presented to study the evolution of spray in the effervescent atomization spray with an impinging plate. For gas phase, the N-S equation with t...Abstract A comprehensive three-dimensional model of droplet-gas flow was presented to study the evolution of spray in the effervescent atomization spray with an impinging plate. For gas phase, the N-S equation with the κ-ε turbulence model was solved, considering two-way coupling interaction between droplets and gas phase. Dispersed droplet phase is modeled as Lagrangian entities, accounting for the physics of droplet generation from primary and secondary breakup, droplet collision and coalescence, droplet momentum and heat transfer. The mean size and sta- tistical distribution of atomized droplets at various nozzle-to-plate distances were calculated. Some simulation resuits were compared well with experimental data. The results show that the existence of the impinging plate has a pronounced influence on the droplet mean size, size distribution and the droplet spatial distribution. The air-to-liquid ratio has obvious effects on the droplet size and distribution.展开更多
The study and modeling process of effervescent atomization are reviewed. The mechanism of droplet events and the treatment of liquid fragmentation process and dispersed particles are systematically presented, which in...The study and modeling process of effervescent atomization are reviewed. The mechanism of droplet events and the treatment of liquid fragmentation process and dispersed particles are systematically presented, which includes the primary atomization of Newtonian and non-Newtonian fluid, instability analysis, turbulence treatment, particle tracking, secondary atomization and droplets collision. The review on the sub-models involved in the simulation of effervescence is followed by a summary of the achievements of modeling. First is the validation of models; then the parametric study is summarized; the third part introduces the fitting formula of droplet mean size and impinging factors, and finally the scope of future study is indicated.展开更多
Using fluid dynamics software Fluent, the spray characteristics of an effervescent atomizer in a downstream flow field was simulated and analyzed, the results show that on the cross sections of the atomizer downstream...Using fluid dynamics software Fluent, the spray characteristics of an effervescent atomizer in a downstream flow field was simulated and analyzed, the results show that on the cross sections of the atomizer downstream flow field, the distribution of the atomized droplet size is small and mainly concentrated about Sauter mean diameter （ SMD）, and the distribution of the axial velocity is large, but mainly concentrated about the gas peak velocity in the closer nozzle axis area; the gas peak velocity of the atomized droplet increases, while the droplet SMD decreases with increase of the nozzle caliber and the air pressure; with the increase of the flow rate of cuttingfluid, the atomized droplet SMD increases, while the gas peak velocity rises first and then decreases, but the decrease trend is very small after the air pressure is more than 0. 4 MPa. The simulation results have significance in guiding for designing and applying the effervescent atomizer.展开更多
基金Supported by the Major Program of the National Natural Science Foundation of China （10632070）
文摘Abstract A comprehensive three-dimensional model of droplet-gas flow was presented to study the evolution of spray in the effervescent atomization spray with an impinging plate. For gas phase, the N-S equation with the κ-ε turbulence model was solved, considering two-way coupling interaction between droplets and gas phase. Dispersed droplet phase is modeled as Lagrangian entities, accounting for the physics of droplet generation from primary and secondary breakup, droplet collision and coalescence, droplet momentum and heat transfer. The mean size and sta- tistical distribution of atomized droplets at various nozzle-to-plate distances were calculated. Some simulation resuits were compared well with experimental data. The results show that the existence of the impinging plate has a pronounced influence on the droplet mean size, size distribution and the droplet spatial distribution. The air-to-liquid ratio has obvious effects on the droplet size and distribution.
基金supported by the National Natural Science Foundation of China (Grant Nos.11132008 and 11002136)
文摘The study and modeling process of effervescent atomization are reviewed. The mechanism of droplet events and the treatment of liquid fragmentation process and dispersed particles are systematically presented, which includes the primary atomization of Newtonian and non-Newtonian fluid, instability analysis, turbulence treatment, particle tracking, secondary atomization and droplets collision. The review on the sub-models involved in the simulation of effervescence is followed by a summary of the achievements of modeling. First is the validation of models; then the parametric study is summarized; the third part introduces the fitting formula of droplet mean size and impinging factors, and finally the scope of future study is indicated.
文摘Using fluid dynamics software Fluent, the spray characteristics of an effervescent atomizer in a downstream flow field was simulated and analyzed, the results show that on the cross sections of the atomizer downstream flow field, the distribution of the atomized droplet size is small and mainly concentrated about Sauter mean diameter （ SMD）, and the distribution of the axial velocity is large, but mainly concentrated about the gas peak velocity in the closer nozzle axis area; the gas peak velocity of the atomized droplet increases, while the droplet SMD decreases with increase of the nozzle caliber and the air pressure; with the increase of the flow rate of cuttingfluid, the atomized droplet SMD increases, while the gas peak velocity rises first and then decreases, but the decrease trend is very small after the air pressure is more than 0. 4 MPa. The simulation results have significance in guiding for designing and applying the effervescent atomizer.
