Title:
Experimental study of spray-formation processes in twin-fluid jet-in-crossflow at jet-engine operating conditions
Experimental study of spray-formation processes in twin-fluid jet-in-crossflow at jet-engine operating conditions
| dc.contributor.advisor | Zinn, Ben T. | |
| dc.contributor.advisor | Jagoda, Jechiel I. | |
| dc.contributor.advisor | Seitzman, Jerry M. | |
| dc.contributor.advisor | Genzale, Caroline L. | |
| dc.contributor.advisor | Lubarsky, Eugene | |
| dc.contributor.author | Tan, Zu Puayen | |
| dc.contributor.department | Aerospace Engineering | |
| dc.date.accessioned | 2017-06-07T17:38:52Z | |
| dc.date.available | 2017-06-07T17:38:52Z | |
| dc.date.created | 2017-05 | |
| dc.date.issued | 2017-01-05 | |
| dc.date.submitted | May 2017 | |
| dc.date.updated | 2017-06-07T17:38:52Z | |
| dc.description.abstract | The jet-in-crossflow (JICF) fuel-injection technique is widely applied in modern jet-engine fuel-air mixers to provide rapid fuel atomization and mixing. However, the “Classical” JICF places large amounts of fuel into the initial jet/spray’s recirculation zone and the wall boundary-layer, both of which can risk flashback and fuel-coking on the wall, particularly for next-generation jet-engines that will operate at increasingly higher pressures and temperatures. Twin-Fluid (TF) JICF, where streams of air are co-injected with the fuel jet into the crossflow, is being considered as a way to mitigate the Classical-JICF’s shortcomings. However, the TF-JICF is a nascent fuel-injection technique that is not well understood, especially at the high operating pressures of jet-engines. This dissertation reports an experimental investigation of TF-JICF where liquid Jet-A fuel was co-injected with pressurized nitrogen into a crossflow of air. The developed fuel sprays were characterized using shadowgraphy. The fuel-to-crossflow momentum-flux ratios were varied from J=5-40, the air-nozzles pressure-drops were varied from dP=0-150% of crossflow pressure, and the crossflow Weber numbers were varied from Wecf=175-1050. These operating conditions allowed us to obtain a dataset that is both comparable with near-atmospheric studies of TF-JICF in the literature and applicable to jet-engines. The results show that TF-JICF can be classified into four spray-formation regimes (i.e., Classical-JICF, Air-Assist JICF, Airblast JICF and Airblast Spray-in-Crossflow), each containing a unique set of spray characteristics and mechanisms. In the Air-Assist regime that spans dP≈3-13%, the injected air formed a protective air-sheath around the initial fuel jet, which inhibited the development of Rayleigh-Taylor waves and surface-shearing (i.e., disturbances created by the crossflow), thus reducing the near-wall fuel concentrations. Applying higher levels of dP transitioned the spray into the Airblast JICF regime, where the intensified fuel-air impingement and shearing generated new disturbances on the jet. These generally caused the near-wall regions to become repopulated with fuel droplets (i.e., counter-productive towards mitigating flashback and wall-coking). When dP was higher than 100%, the jet became completely atomized by air prior to encountering the crossflow, producing an “Airblast Spray-in-Crossflow”. The resulting spray-plume’s penetration became related to the combination of the fuel and air’s momentum-fluxes, where increasing dP caused increasing separation between the spray-plume and test-channel wall. This reduces the near-wall fuel concentrations and is beneficial towards fuel-air mixer design, although the required levels of dP for this regime is likely too high for practical jet-engine operation. | |
| dc.description.degree | Ph.D. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/1853/58214 | |
| dc.language.iso | en_US | |
| dc.publisher | Georgia Institute of Technology | |
| dc.subject | Jet-in-crossflow | |
| dc.subject | Cross-flow | |
| dc.subject | Transverse jet | |
| dc.subject | Twin-fluid | |
| dc.subject | Airblast | |
| dc.subject | Air-assist | |
| dc.subject | Spray | |
| dc.subject | Penetration | |
| dc.subject | Trajectory | |
| dc.subject | Fuel-injection | |
| dc.subject | Jet-engine | |
| dc.subject | Atomization regime | |
| dc.subject | Experimental study | |
| dc.subject | Shadowgraph | |
| dc.subject | High pressure | |
| dc.subject | High Weber number | |
| dc.title | Experimental study of spray-formation processes in twin-fluid jet-in-crossflow at jet-engine operating conditions | |
| dc.type | Text | |
| dc.type.genre | Dissertation | |
| dspace.entity.type | Publication | |
| local.contributor.advisor | Jagoda, Jechiel I. | |
| local.contributor.advisor | Zinn, Ben T. | |
| local.contributor.advisor | Seitzman, Jerry M. | |
| local.contributor.advisor | Genzale, Caroline L. | |
| local.contributor.corporatename | College of Engineering | |
| local.contributor.corporatename | Daniel Guggenheim School of Aerospace Engineering | |
| local.relation.ispartofseries | Doctor of Philosophy with a Major in Aerospace Engineering | |
| relation.isAdvisorOfPublication | 82d8814b-a147-40a3-908d-cb7a4766cdbe | |
| relation.isAdvisorOfPublication | 982cb5ab-69b0-484e-b11e-931f10649bd8 | |
| relation.isAdvisorOfPublication | a312077b-cd16-4664-ad12-3a719b7f798a | |
| relation.isAdvisorOfPublication | cf75f195-428a-44e9-8ab1-54a2be994f83 | |
| relation.isOrgUnitOfPublication | 7c022d60-21d5-497c-b552-95e489a06569 | |
| relation.isOrgUnitOfPublication | a348b767-ea7e-4789-af1f-1f1d5925fb65 | |
| relation.isSeriesOfPublication | f6a932db-1cde-43b5-bcab-bf573da55ed6 | |
| thesis.degree.level | Doctoral |