In this work,the spray behaviors of a rotary atomizer with round-shaped injection orifices are experimentally investigated to study the breakup mechanism and spray characteristics using RP-3 as the liquid fuel.The bre...In this work,the spray behaviors of a rotary atomizer with round-shaped injection orifices are experimentally investigated to study the breakup mechanism and spray characteristics using RP-3 as the liquid fuel.The breakup process of the liquid is visualized by the backlight shadow imaging method,which also provides the measurements of liquid breakup length and penetration height.The injection mode of the liquid film is observed using the front-light illumination method.The droplet size and distribution are measured using the laser particle size analyzer at various radial locations.Three typical breakup modes are identified:the ligament breakup mode,bag breakup mode,and shear breakup mode.Aerodynamic Weber number(Wed)and momentum flux ratio(q)are used to elaborate the liquid breakup regimes.Results of droplet sizing indicate that the Sauter mean diameter decreases with a higher rotational speed and slightly varies with the volume flow rate.A correlation between liquid breakup modes and non-dimensional droplet size is established based on Wed and q.This study presents some significance for understanding the impacts of the rotational speed and volume flow rates on the spray performance of actual aviation fuels in rotary atomizers.展开更多
Small unmanned aerial vehicle(UAV)pesticide application technology is developing rapidly in China.However,the spray efficiency of UAV sprayer is not stable,one important reason is that the lack of specialized aviation...Small unmanned aerial vehicle(UAV)pesticide application technology is developing rapidly in China.However,the spray efficiency of UAV sprayer is not stable,one important reason is that the lack of specialized aviation nozzle.Rotary cup atomizer is not easily to be blocked and has broad application foreground in UAV spray.In order to obtain good spraying quality and narrow droplet spectrum aviation spraying centrifugal nozzle,the impacts of rotary cup atomizer structural parameters on atomization property were studied.In this research,a centrifugal atomization test device was designed,on which a frequency converter was used to adjust the rotary speed,and a return valve was used to stabilize the flow rate and pressure of spray liquid.The droplet volume medium diameter(VMD)and droplet spectrum relative width(SRW)were tested by using laser particle analyzer and particle analysis system.The analysis results of variance and quadratic regression orthogonal test were used to optimize the structural parameters of rotary cup atomizer.The influences of rotary cup atomizer structural parameters on atomization property,such as groove shape,diameter,teeth number,cone angle and height were evaluated and analyzed by conducting single-factor test.The results showed that:the best optimized rotary groove shape was square,diameter and teeth number had significant effects on droplet VMD and SRW,while cone angle had no effect on the droplet VMD and SRW,height affected droplet VMDbut did not affect droplet SRW.Therefore,diameter and teeth number were selected as the variables of quadratic regression orthogonal test,droplet VMD and SRW regression model was established by using response surface analysis method.The optimized structural parameters respectively were:groove shape square,cone angle 60°,height 20 mm,diameter 61.5 mm and teeth number 149.Droplet VMD and SRW simulation value respectively were 200μm and 0.562.The differences between simulation value and test value were 0.68%and 9.90%respectively,indicating that the regression model is accurate.The research result can provide a reference for further optimizing the structure parameters of rotary cup atomizer to meet the requirement of UAV spraying.展开更多
Slinger is a rotary atomizer whose atomization performance is affected by the parameters of orifice.8 kinds of orifices with different structure parameters were investigated,and an optimal diameter exists for the roun...Slinger is a rotary atomizer whose atomization performance is affected by the parameters of orifice.8 kinds of orifices with different structure parameters were investigated,and an optimal diameter exists for the round orifice with that the spray SMD is the smallest and the uniformity is the best.Increases in the axial length of slot orifice decrease the spray SMD and improve the spray uniformity,but increases in the width of the slot orifice are invalid for liquid spray SMD,and the spray uniformity becomes even worse.In most cases,the spray SMD of slot orifice is smaller than that of round orifice with the same perimeter,and the spray uniformity is better likewise.Increases in radial length of orifice cause the spray SMD to be larger,but the spray uniformity become obviously better.The spray SMD become larger with decreases in liquid surface tension.The spray uniformity became better nevertheless.展开更多
A novel granulation process that involved the use of a rotary multi-nozzles cup atomizer and water cooling was proposed for ferroalloy manufacturing.The effects of rotating speed and nozzle diameter on the properties ...A novel granulation process that involved the use of a rotary multi-nozzles cup atomizer and water cooling was proposed for ferroalloy manufacturing.The effects of rotating speed and nozzle diameter on the properties of FeSi75 alloy(containing 75 wt.%Si)granules were investigated.Results indicated that median granule diameter decreased as rotating speed in creased,and initially increased and then decreased as nozzle diameter in creased.The optimal conditi ons for the gra nulation of FeSi75 alloy were a rotating speed of 150 r/min and nozzle diameter of 10 or 12 mm.The phase composition,micromorphology,and elemental distribution of the FeSi75 alloy granules were also studied by X-ray diffraction,scanning electron microscopy,and energy-dispersive X-ray spectrometry.In order to provide guidance for the layout and water depth of the tank,the solidification behavior of ferrosilicon alloy droplet was numerically studied.A simplified model was established to elucidate the traveling trajectory and heat transfer of alloy droplet in air and cooling water during the atomization process.The solidification time of droplet with different thicknesses of solidification layer increased with the in crease in alloy droplet diameter.展开更多
Slinger is a type of rotary atomizer wherein spray spatial distribution varies with the rotary speed and mass flowrate.The spray parameters at a series of locations in the radial direction of the slinger were measured...Slinger is a type of rotary atomizer wherein spray spatial distribution varies with the rotary speed and mass flowrate.The spray parameters at a series of locations in the radial direction of the slinger were measured and the parameters of the location where the spray Sauter Mean Diameter(SMD)corresponds to the smallest were selected to be analyzed.The results indicated that at a specific mass flowrate,an optimum diameter exists for the orifice,in which the orifice’s spray corresponds to the smallest and most uniform.Increases in the mass flowrate increase the optimum diameter.Further,the spray from the circular orifice is more uniform compared with that from the slot orifice with the same circumference.When the length of the orifice increases,the spray becomes larger but more uniform.The liquid regime in the orifice affects primary atomization of the liquid,significantly affecting the spray SMD and uniformity.展开更多
A theoretical and experimental investigation on the liquid breakup regimes of slinger is presented in this paper.The theoretical results show that in the round orifice of the slinger,if the contact angle between the l...A theoretical and experimental investigation on the liquid breakup regimes of slinger is presented in this paper.The theoretical results show that in the round orifice of the slinger,if the contact angle between the liquid and the wall is less than 90°,the liquid surface tension will inhibit the liquid lateral flowing under the Coriolis force.The formula used to predict the liquid regime leaving the orifice in the past was proved to be inaccurate,which is explained by two assumptions presented in this paper.The breakup regimes of the liquid film are related to the Weber number,and the characteristic length of the Weber number is equivalent to the thickness of the liquid film.The liquid film performed subcritical breakup when the Weber number was small and performed supercritical breakup when the Weber number was large.But when the Weber number was in the middle state,the breakup regimes could not be determined.The liquid breakup regimes affected the primary breakup of the liquid,but a lot of tiny droplets were produced in the secondary breakup,which led to poor correlation between the spray Sauter Mean Diameter(SMD)and the Weber number corresponding to various liquid breakup regimes.On the whole,the spray SMD performs a power relationship with the Weber number corresponding to the liquid film regime,and the correlation coefficient is close to 0.9.展开更多
基金supported by the National Science and Technology Major Project of China(Grant No.J2019-III-0006-0049).
文摘In this work,the spray behaviors of a rotary atomizer with round-shaped injection orifices are experimentally investigated to study the breakup mechanism and spray characteristics using RP-3 as the liquid fuel.The breakup process of the liquid is visualized by the backlight shadow imaging method,which also provides the measurements of liquid breakup length and penetration height.The injection mode of the liquid film is observed using the front-light illumination method.The droplet size and distribution are measured using the laser particle size analyzer at various radial locations.Three typical breakup modes are identified:the ligament breakup mode,bag breakup mode,and shear breakup mode.Aerodynamic Weber number(Wed)and momentum flux ratio(q)are used to elaborate the liquid breakup regimes.Results of droplet sizing indicate that the Sauter mean diameter decreases with a higher rotational speed and slightly varies with the volume flow rate.A correlation between liquid breakup modes and non-dimensional droplet size is established based on Wed and q.This study presents some significance for understanding the impacts of the rotational speed and volume flow rates on the spray performance of actual aviation fuels in rotary atomizers.
基金the National Key Research and Development Plan(No.2016YFD0200702)2012 Foundation Project of Technology Innovation for Graduate in Jiangsu Province of China(No.CXLX12_0658)+4 种基金Special Fund for Agro-scientific Research in the Public Interest(No.201203025)National High Technology Research and Development Program of China(863 program,2013AA102303)Synergistic Innovation Center of Modern Agricultural Equipment and Technology in Jiangsu Province(NZXT01201403)Agriculture Intelligent Equipment and Technology Research Key Laboratory Open Research Topic in Jiangsu province(NZ201005)the Natural Science Foundation of Jiangsu Province,China(BK 20151074).
文摘Small unmanned aerial vehicle(UAV)pesticide application technology is developing rapidly in China.However,the spray efficiency of UAV sprayer is not stable,one important reason is that the lack of specialized aviation nozzle.Rotary cup atomizer is not easily to be blocked and has broad application foreground in UAV spray.In order to obtain good spraying quality and narrow droplet spectrum aviation spraying centrifugal nozzle,the impacts of rotary cup atomizer structural parameters on atomization property were studied.In this research,a centrifugal atomization test device was designed,on which a frequency converter was used to adjust the rotary speed,and a return valve was used to stabilize the flow rate and pressure of spray liquid.The droplet volume medium diameter(VMD)and droplet spectrum relative width(SRW)were tested by using laser particle analyzer and particle analysis system.The analysis results of variance and quadratic regression orthogonal test were used to optimize the structural parameters of rotary cup atomizer.The influences of rotary cup atomizer structural parameters on atomization property,such as groove shape,diameter,teeth number,cone angle and height were evaluated and analyzed by conducting single-factor test.The results showed that:the best optimized rotary groove shape was square,diameter and teeth number had significant effects on droplet VMD and SRW,while cone angle had no effect on the droplet VMD and SRW,height affected droplet VMDbut did not affect droplet SRW.Therefore,diameter and teeth number were selected as the variables of quadratic regression orthogonal test,droplet VMD and SRW regression model was established by using response surface analysis method.The optimized structural parameters respectively were:groove shape square,cone angle 60°,height 20 mm,diameter 61.5 mm and teeth number 149.Droplet VMD and SRW simulation value respectively were 200μm and 0.562.The differences between simulation value and test value were 0.68%and 9.90%respectively,indicating that the regression model is accurate.The research result can provide a reference for further optimizing the structure parameters of rotary cup atomizer to meet the requirement of UAV spraying.
文摘Slinger is a rotary atomizer whose atomization performance is affected by the parameters of orifice.8 kinds of orifices with different structure parameters were investigated,and an optimal diameter exists for the round orifice with that the spray SMD is the smallest and the uniformity is the best.Increases in the axial length of slot orifice decrease the spray SMD and improve the spray uniformity,but increases in the width of the slot orifice are invalid for liquid spray SMD,and the spray uniformity becomes even worse.In most cases,the spray SMD of slot orifice is smaller than that of round orifice with the same perimeter,and the spray uniformity is better likewise.Increases in radial length of orifice cause the spray SMD to be larger,but the spray uniformity become obviously better.The spray SMD become larger with decreases in liquid surface tension.The spray uniformity became better nevertheless.
基金the National Natural Science Foundation of China(Grant No.2018YFC1900501)Graduate Scientific Research and Innovation Foundation of Chongqing(CYB19003).
文摘A novel granulation process that involved the use of a rotary multi-nozzles cup atomizer and water cooling was proposed for ferroalloy manufacturing.The effects of rotating speed and nozzle diameter on the properties of FeSi75 alloy(containing 75 wt.%Si)granules were investigated.Results indicated that median granule diameter decreased as rotating speed in creased,and initially increased and then decreased as nozzle diameter in creased.The optimal conditi ons for the gra nulation of FeSi75 alloy were a rotating speed of 150 r/min and nozzle diameter of 10 or 12 mm.The phase composition,micromorphology,and elemental distribution of the FeSi75 alloy granules were also studied by X-ray diffraction,scanning electron microscopy,and energy-dispersive X-ray spectrometry.In order to provide guidance for the layout and water depth of the tank,the solidification behavior of ferrosilicon alloy droplet was numerically studied.A simplified model was established to elucidate the traveling trajectory and heat transfer of alloy droplet in air and cooling water during the atomization process.The solidification time of droplet with different thicknesses of solidification layer increased with the in crease in alloy droplet diameter.
基金the National Natural Science Foundation of China(Grant No.51506003).
文摘Slinger is a type of rotary atomizer wherein spray spatial distribution varies with the rotary speed and mass flowrate.The spray parameters at a series of locations in the radial direction of the slinger were measured and the parameters of the location where the spray Sauter Mean Diameter(SMD)corresponds to the smallest were selected to be analyzed.The results indicated that at a specific mass flowrate,an optimum diameter exists for the orifice,in which the orifice’s spray corresponds to the smallest and most uniform.Increases in the mass flowrate increase the optimum diameter.Further,the spray from the circular orifice is more uniform compared with that from the slot orifice with the same circumference.When the length of the orifice increases,the spray becomes larger but more uniform.The liquid regime in the orifice affects primary atomization of the liquid,significantly affecting the spray SMD and uniformity.
文摘A theoretical and experimental investigation on the liquid breakup regimes of slinger is presented in this paper.The theoretical results show that in the round orifice of the slinger,if the contact angle between the liquid and the wall is less than 90°,the liquid surface tension will inhibit the liquid lateral flowing under the Coriolis force.The formula used to predict the liquid regime leaving the orifice in the past was proved to be inaccurate,which is explained by two assumptions presented in this paper.The breakup regimes of the liquid film are related to the Weber number,and the characteristic length of the Weber number is equivalent to the thickness of the liquid film.The liquid film performed subcritical breakup when the Weber number was small and performed supercritical breakup when the Weber number was large.But when the Weber number was in the middle state,the breakup regimes could not be determined.The liquid breakup regimes affected the primary breakup of the liquid,but a lot of tiny droplets were produced in the secondary breakup,which led to poor correlation between the spray Sauter Mean Diameter(SMD)and the Weber number corresponding to various liquid breakup regimes.On the whole,the spray SMD performs a power relationship with the Weber number corresponding to the liquid film regime,and the correlation coefficient is close to 0.9.
