{"id":{"repo_id":"toronto-retro","oai_identifier":"oai:utoronto.scholaris.ca:1807/123346"},"canonical_url":"https://search.dev.ndltd.org/etd/toronto-retro/oai:utoronto.scholaris.ca:1807/123346","repository":{"repo_id":"toronto-retro","name":"University of Toronto","base_url":"https://utoronto.scholaris.ca/server/oai/request"},"display":{"title":"Liquid Atomization by an Electrostatic Rotating Bell Atomizer and Spray Deposition on Solid Surfaces","abstract":"In an electrostatic rotating bell (ESRB) atomizer, fluid is driven from a central orifice over the bell-cup’s surface towards its edge by the centrifugal force. After the fluid is ejected, it breaks up into droplets. Images of these spray droplets were captured using a DropSizer while operating the bell-cup at various angular frequencies (ω). After processing the images to obtain the droplet sizes, the Sauter mean diameter (SMD) was found to decrease as the angular frequency was increased. Furthermore, a stretching rate γ ̇=ω^2 R/U ̅, where R is the distance from the axis of rotation, was derived for ligaments ejected from a serrated bell-cup and it was shown that the SMD ∝ γ ̇^(-0.5).To determine how spray droplets cover a surface, images of an ESRB atomizer spraying a 20 wt% aqueous glycerol solution on a vertical glass substrate were captured from behind using a high-speed camera. The fraction of surface area coverage was obtained by processing each image. An analytical model was developed based on probability theory and used to predict, with good agreement, the fraction of surface covered by solely using the rate of droplet impingement and the droplet size. A minimum theoretical film thickness assuming full coverage was derived from the probabilistic model; when divided by the droplet diameter, it was found to be dependent only on the droplet spread factor. Droplet/surface interaction is not limited to spreading and drawback when spray droplets impinge on surfaces that are porous. As such, water was atomized using a full-cone nozzle and sprayed onto various vertical stainless-steel meshes. The mass of liquid that penetrated the mesh was measured using a scale, and images of each mesh surface were captured during droplet impingement. It was observed that droplets that landed near unblocked pores of a mesh were leached by neighbouring pools of liquid, delaying the blockage of some pores. A stochastic model, developed to determine the mass of liquid that penetrates a vertical mesh, compared well with experimental measurements. In the model, the volume required to block a pore was a function of the number of surrounding blocked pores and the mesh’s open-area ratio.","abstract_html":"In an electrostatic rotating bell (ESRB) atomizer, fluid is driven from a central orifice over the bell-cup’s surface towards its edge by the centrifugal force. After the fluid is ejected, it breaks up into droplets. Images of these spray droplets were captured using a DropSizer while operating the bell-cup at various angular frequencies (ω). After processing the images to obtain the droplet sizes, the Sauter mean diameter (SMD) was found to decrease as the angular frequency was increased. Furthermore, a stretching rate γ ̇=ω^2 R/U ̅, where R is the distance from the axis of rotation, was derived for ligaments ejected from a serrated bell-cup and it was shown that the SMD ∝ γ ̇^(-0.5).To determine how spray droplets cover a surface, images of an ESRB atomizer spraying a 20 wt% aqueous glycerol solution on a vertical glass substrate were captured from behind using a high-speed camera. The fraction of surface area coverage was obtained by processing each image. An analytical model was developed based on probability theory and used to predict, with good agreement, the fraction of surface covered by solely using the rate of droplet impingement and the droplet size. A minimum theoretical film thickness assuming full coverage was derived from the probabilistic model; when divided by the droplet diameter, it was found to be dependent only on the droplet spread factor. Droplet/surface interaction is not limited to spreading and drawback when spray droplets impinge on surfaces that are porous. As such, water was atomized using a full-cone nozzle and sprayed onto various vertical stainless-steel meshes. The mass of liquid that penetrated the mesh was measured using a scale, and images of each mesh surface were captured during droplet impingement. It was observed that droplets that landed near unblocked pores of a mesh were leached by neighbouring pools of liquid, delaying the blockage of some pores. A stochastic model, developed to determine the mass of liquid that penetrates a vertical mesh, compared well with experimental measurements. In the model, the volume required to block a pore was a function of the number of surrounding blocked pores and the mesh’s open-area ratio.","abstract_has_math":false,"creators":["Sidawi, Khalil"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Mechanical and Industrial Engineering","school":null,"contributors":[],"advisors":["Chandra, Sanjeev"],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-06","date_published":"2022-06","updated_at":"2026-07-27T21:28:18Z","subjects":["Atomization","Coatings","ESRB Atomizers","Liquid Films","Sprays","Surface Coverage"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1807/123346","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Chandra, Sanjeev"]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical and Industrial Engineering"]},{"key":"dc:creator","label":"Author","values":["Sidawi, Khalil"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-06"]},{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2022-06-29T15:51:46Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2022-06-29T15:51:46Z"]},{"key":"dc:date.issued","label":"Date","values":["2022-06"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Atomization","Coatings","ESRB Atomizers","Liquid Films","Sprays","Surface Coverage"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1807/123346"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In an electrostatic rotating bell (ESRB) atomizer, fluid is driven from a central orifice over the bell-cup’s surface towards its edge by the centrifugal force. After the fluid is ejected, it breaks up into droplets. Images of these spray droplets were captured using a DropSizer while operating the bell-cup at various angular frequencies (ω). After processing the images to obtain the droplet sizes, the Sauter mean diameter (SMD) was found to decrease as the angular frequency was increased. Furthermore, a stretching rate γ ̇=ω^2 R/U ̅, where R is the distance from the axis of rotation, was derived for ligaments ejected from a serrated bell-cup and it was shown that the SMD ∝ γ ̇^(-0.5).To determine how spray droplets cover a surface, images of an ESRB atomizer spraying a 20 wt% aqueous glycerol solution on a vertical glass substrate were captured from behind using a high-speed camera. The fraction of surface area coverage was obtained by processing each image. An analytical model was developed based on probability theory and used to predict, with good agreement, the fraction of surface covered by solely using the rate of droplet impingement and the droplet size. A minimum theoretical film thickness assuming full coverage was derived from the probabilistic model; when divided by the droplet diameter, it was found to be dependent only on the droplet spread factor. Droplet/surface interaction is not limited to spreading and drawback when spray droplets impinge on surfaces that are porous. As such, water was atomized using a full-cone nozzle and sprayed onto various vertical stainless-steel meshes. The mass of liquid that penetrated the mesh was measured using a scale, and images of each mesh surface were captured during droplet impingement. It was observed that droplets that landed near unblocked pores of a mesh were leached by neighbouring pools of liquid, delaying the blockage of some pores. A stochastic model, developed to determine the mass of liquid that penetrates a vertical mesh, compared well with experimental measurements. In the model, the volume required to block a pore was a function of the number of surrounding blocked pores and the mesh’s open-area ratio."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph.D."]},{"key":"dc:title","label":"Title","values":["Liquid Atomization by an Electrostatic Rotating Bell Atomizer and Spray Deposition on Solid Surfaces"]}]}],"canonical_facts":{"dc:contributor.advisor":["Chandra, Sanjeev"],"dc:contributor.department":["Mechanical and Industrial Engineering"],"dc:creator":["Sidawi, Khalil"],"dc:date":["2022-06"],"dc:date.accessioned":["2022-06-29T15:51:46Z"],"dc:date.available":["2022-06-29T15:51:46Z"],"dc:date.issued":["2022-06"],"dc:description.abstract":["In an electrostatic rotating bell (ESRB) atomizer, fluid is driven from a central orifice over the bell-cup’s surface towards its edge by the centrifugal force. After the fluid is ejected, it breaks up into droplets. Images of these spray droplets were captured using a DropSizer while operating the bell-cup at various angular frequencies (ω). After processing the images to obtain the droplet sizes, the Sauter mean diameter (SMD) was found to decrease as the angular frequency was increased. Furthermore, a stretching rate γ ̇=ω^2 R/U ̅, where R is the distance from the axis of rotation, was derived for ligaments ejected from a serrated bell-cup and it was shown that the SMD ∝ γ ̇^(-0.5).To determine how spray droplets cover a surface, images of an ESRB atomizer spraying a 20 wt% aqueous glycerol solution on a vertical glass substrate were captured from behind using a high-speed camera. The fraction of surface area coverage was obtained by processing each image. An analytical model was developed based on probability theory and used to predict, with good agreement, the fraction of surface covered by solely using the rate of droplet impingement and the droplet size. A minimum theoretical film thickness assuming full coverage was derived from the probabilistic model; when divided by the droplet diameter, it was found to be dependent only on the droplet spread factor. Droplet/surface interaction is not limited to spreading and drawback when spray droplets impinge on surfaces that are porous. As such, water was atomized using a full-cone nozzle and sprayed onto various vertical stainless-steel meshes. The mass of liquid that penetrated the mesh was measured using a scale, and images of each mesh surface were captured during droplet impingement. It was observed that droplets that landed near unblocked pores of a mesh were leached by neighbouring pools of liquid, delaying the blockage of some pores. A stochastic model, developed to determine the mass of liquid that penetrates a vertical mesh, compared well with experimental measurements. In the model, the volume required to block a pore was a function of the number of surrounding blocked pores and the mesh’s open-area ratio."],"dc:description.degree":["Ph.D."],"dc:identifier.uri":["http://hdl.handle.net/1807/123346"],"dc:subject":["Atomization","Coatings","ESRB Atomizers","Liquid Films","Sprays","Surface Coverage"],"dc:title":["Liquid Atomization by an Electrostatic Rotating Bell Atomizer and Spray Deposition on Solid Surfaces"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T21:28:18Z"}