Numerical And Experimental Study On The Electrospray Under Different Electrode Structures

Compared with other atomization methods,the droplets obtained by electrostatic atomization have a smaller particle size,good monodispersity,and the droplets are difficult to polymerize due to the charge with the same polarity.And the purpose of controlling the droplet movement can be achieved by controlling the electrostatic field.Due to its superior atomization characteristics,charged atomization technology has broad application prospects in the field of charged atomization combustion.Electrode structure is an important factor affecting the charging effect of droplets.In order to rationally design the charged atomization device,the charged spray device based on the two electrode structures of capillary nozzle-ground electrode and capillary nozzle-ring electrode-ground electrode uses innovatively curved surface as ground electrode.The curvature radius of the curved ground electrode and the inner diameter and thickness of the ring electrode were changed to conduct an experimental study on ethanol atomization.Use the grid target method to obtain the atomization current and calculate the important electrical parameter charge-to-mass ratio;use the phase Doppler particle velometer PDA to collect data on the droplet size and velocity at the space measurement point;Spray form,treatment to obtain atomization cone angle.Through the numerical simulation method,the spatial electric field distribution under different electrode structures is obtained,and the droplet velocity distribution and flow field distribution under different ground electrode curvature radius are obtained.Combined with the experimental data,the charged droplet size distribution and velocity distribution are analyzed Law,study the mechanism of charge atomization droplet breakage.The results show that when the thickness of the ring electrode is increased or the inner diameter of the ring electrode is reduced,the radial electric field strength around the ring electrode increases,but the axial field strength does not change significantly;the change in the electric field makes the thickness of the ring electrode larger or When the inner diameter of the ring electrode is smaller,the spray is more divergent,the droplet charge-to-mass ratio is larger,and the charging effect is better.The spray cone angle and the charge-to-mass ratio increase with the decrease of the ring electrode's inner diameter or the thickness.The thickness of the ring electrode is larger or the inner diameter is smaller.Because of the large electric field strength and good charging effect,the ring electrode can produce a spray with a smaller droplet size and a more uniform distribution.When the radius of curvature of the ground electrode decreases,it is found that the radial electric field intensity in space increases,the axial electric field intensity near the spray area decreases,and the axial electric field intensity near the ground electrode area increases.Therefore,the smaller the radius of curvature of the ground electrode,the closer to the nozzle area,the droplets are less likely to coalesce,and the smaller the droplet size,the faster the droplet movement speed.When the radius of curvature of the ground electrode is 50 mm,the monodispersity of the final stabilized droplet size is the best,the droplet velocity is small and the distribution is uniform,and the spray atomization characteristics are superior.Decreasing the flow rate will also reduce the droplet size and increase the velocity,which will affect the spray characteristics.