In this paper, we investigate the effects of an imposed axial flow on hydrodynamic instabilities’ Couette-Taylor flow in the case where the wall of the inner cylinder of the system is grouved. Without imposed axial flow, the basic flow of a fluid between two coaxial cylinders known by Couette flow, which is characterized by several temporal and spatial symmetries. The increase in the rotation causes the breaking of these symmetries. In both cases where the surface of the inner cylinder is smooth and grooved, five different flow regimes can be determined: Taylor vortex flow (TVF), wavy vortex flow (WVF), and Modulated Wavy vortex flow (MWVF). Each time the flow passes from one hydrodynamic regime to another until it enters a state of turbulence, which is characterized by the destruction of all the symmetries that existed at the beginning. In addition, when an axial flow is imposed on a Taylor-Couette flow, new helical vortex structures are observed in both cases (with and without surface groove). The influence of surface structures (grooves) on the shear stress of the wall is discussed with and without axial base flow. A spatio-temporal description of several flow models was obtained using firstly, a visualization’s qualitative study using kalliroscope particles. Secondly, a quantitative study by polarography using simple probes have been used to characterize the impact of vortex structures on the Couette-Taylor flows without and with an axial flow on the transfer.
{"title":"Experimental Investigations of the Surface Groove Effect in Taylor-Couette-Poiseuille Flow","authors":"Lamia Gaied, F. Aloui, M. Lippert, Emna Berrich","doi":"10.1115/fedsm2020-20326","DOIUrl":"https://doi.org/10.1115/fedsm2020-20326","url":null,"abstract":"\u0000 In this paper, we investigate the effects of an imposed axial flow on hydrodynamic instabilities’ Couette-Taylor flow in the case where the wall of the inner cylinder of the system is grouved.\u0000 Without imposed axial flow, the basic flow of a fluid between two coaxial cylinders known by Couette flow, which is characterized by several temporal and spatial symmetries. The increase in the rotation causes the breaking of these symmetries.\u0000 In both cases where the surface of the inner cylinder is smooth and grooved, five different flow regimes can be determined: Taylor vortex flow (TVF), wavy vortex flow (WVF), and Modulated Wavy vortex flow (MWVF). Each time the flow passes from one hydrodynamic regime to another until it enters a state of turbulence, which is characterized by the destruction of all the symmetries that existed at the beginning.\u0000 In addition, when an axial flow is imposed on a Taylor-Couette flow, new helical vortex structures are observed in both cases (with and without surface groove).\u0000 The influence of surface structures (grooves) on the shear stress of the wall is discussed with and without axial base flow. A spatio-temporal description of several flow models was obtained using firstly, a visualization’s qualitative study using kalliroscope particles. Secondly, a quantitative study by polarography using simple probes have been used to characterize the impact of vortex structures on the Couette-Taylor flows without and with an axial flow on the transfer.","PeriodicalId":103887,"journal":{"name":"Volume 1: Fluid Applications and Systems; Fluid Measurement and Instrumentation","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134272095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi Chen, Abhay V. Patil, Yiming Chen, G. Morrison, M. Rojas
Electrical submersible pump (ESP) technology has been widely applied in the oil and gas industry due to its high productivity. However, erosion always causes the reduction of productivity and sometimes even the failure of an ESP system. This study explores the effect of gas presence on erosion mechanism on an ESP which is composed of 4 stages of Helico-Axial Pump (HAP). A 200-hour erosion test has been performed on this ESP. During the test, the ESP was running at 3600 RPM with a liquid flow rate of 880 GPM, 20% inlet Gas Volume Fraction (GVF), and 0.24% sand concentration by weight. Performance tests were conducted every 50 hours to acquire the performance maps and monitor the performance degradation. Analysis of volume/weight loss and performance degradation is conducted to investigate pump wear. Two types of erosion are found at the impeller: the volume loss found notably at the leading edge is mainly caused by two-body impact erosion, while the tip clearance increment between the impeller housing and impeller blade tip is mainly caused by the three-body abrasive erosion. Unlike most conventional centrifugal pumps, there is no observable wear found at the trailing edge of the impeller. The presence of the gas shows a negative effect on both types of erosion. The consequence of the erosion is the performance degradation, especially at the condition with higher pressure rise. It is suggested to apply this HAP in the oil field with more gas and higher bottom hole pressure.
{"title":"An Experimental Investigation on the Erosion of a Helico-Axial Pump With Gas Presence","authors":"Yi Chen, Abhay V. Patil, Yiming Chen, G. Morrison, M. Rojas","doi":"10.1115/fedsm2020-20481","DOIUrl":"https://doi.org/10.1115/fedsm2020-20481","url":null,"abstract":"\u0000 Electrical submersible pump (ESP) technology has been widely applied in the oil and gas industry due to its high productivity. However, erosion always causes the reduction of productivity and sometimes even the failure of an ESP system. This study explores the effect of gas presence on erosion mechanism on an ESP which is composed of 4 stages of Helico-Axial Pump (HAP). A 200-hour erosion test has been performed on this ESP. During the test, the ESP was running at 3600 RPM with a liquid flow rate of 880 GPM, 20% inlet Gas Volume Fraction (GVF), and 0.24% sand concentration by weight. Performance tests were conducted every 50 hours to acquire the performance maps and monitor the performance degradation. Analysis of volume/weight loss and performance degradation is conducted to investigate pump wear. Two types of erosion are found at the impeller: the volume loss found notably at the leading edge is mainly caused by two-body impact erosion, while the tip clearance increment between the impeller housing and impeller blade tip is mainly caused by the three-body abrasive erosion. Unlike most conventional centrifugal pumps, there is no observable wear found at the trailing edge of the impeller. The presence of the gas shows a negative effect on both types of erosion. The consequence of the erosion is the performance degradation, especially at the condition with higher pressure rise. It is suggested to apply this HAP in the oil field with more gas and higher bottom hole pressure.","PeriodicalId":103887,"journal":{"name":"Volume 1: Fluid Applications and Systems; Fluid Measurement and Instrumentation","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127994972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Previous research on firefighting aircraft which employ dumping water from their lower surface to extinguish flames has shown that there are added lift benefits during dumping maneuvers which do not directly correlate to the exchange in water mass. In this case study, the effects of liquid spray formations on two dimensional aerodynamics are investigated by use of a numerical approach. Studies include chord-wise variation of liquid-jets and variation of spray momentum ratios. Comparisons are also made to previous, single-phase, jet-flap numerical experiments and show favorable agreement. Findings show that increases in lift coefficient and decreases in drag coefficient are observed with the presences of liquid jets located on the lower surface.
{"title":"Using Liquid Spray Formations to Improve Aerodynamic Performance of Airfoils","authors":"G. Loubimov, D. Fontes, Garett Loving, M. Kinzel","doi":"10.1115/fedsm2020-20078","DOIUrl":"https://doi.org/10.1115/fedsm2020-20078","url":null,"abstract":"\u0000 Previous research on firefighting aircraft which employ dumping water from their lower surface to extinguish flames has shown that there are added lift benefits during dumping maneuvers which do not directly correlate to the exchange in water mass. In this case study, the effects of liquid spray formations on two dimensional aerodynamics are investigated by use of a numerical approach. Studies include chord-wise variation of liquid-jets and variation of spray momentum ratios. Comparisons are also made to previous, single-phase, jet-flap numerical experiments and show favorable agreement. Findings show that increases in lift coefficient and decreases in drag coefficient are observed with the presences of liquid jets located on the lower surface.","PeriodicalId":103887,"journal":{"name":"Volume 1: Fluid Applications and Systems; Fluid Measurement and Instrumentation","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117269881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dispersion characteristics of airborne pathogens were investigated in a Boeing 767 mockup cabin containing 11 rows with 7 seats per row, using two tracer gas source methods: continuous injection at low velocity and a coughing manikin. Both the injection source and the coughing manikin were located on the same seat in the sixth row. The injection source utilized CO2 gas at an injection rate of 5.0 liters per minute mixed with helium at a rate of 3.07 liters per minute to neutralize buoyancy. The manikin coughed approximately once every 75 seconds, with a volume of 4.2 liters of CO2 per cough. To ensure sufficient data were collected at each sampling location, each coughing manikin test was run for 6 coughs and each injection source test for 30 minutes of continuous injection. In both test methods, the tracer gas concentration was measured using CO2 gas analyzers at seated passenger breathing height of 1.2 m and radially up to 3.35 m away from the gas injection location, representing approximately four rows of a standard B767 aircraft. The collected data obtained from each tracer method was then normalized to provide a suitable comparison basis that is independent of tracer gas introduction flowrate. The results showed that both tracer source methods gave similar dispersion trends in diagonal and lateral directions away from the injection location. However, the tracer gas concentration was higher along the longitudinal direction in the coughing manikin tests due to the cough momentum. The results of this work will help researchers analyze different experimental and numerical approaches used to determine contaminant dispersion in various environments and will provide a better understanding of the associated transport phenomena.
{"title":"Comparison of Pathogens Dispersion in an Aircraft Cabin Using Gas Injection Source Versus a Coughing Manikin","authors":"Seif Mahmoud, J. Bennett, M. Hosni, B. Jones","doi":"10.1115/fedsm2020-20095","DOIUrl":"https://doi.org/10.1115/fedsm2020-20095","url":null,"abstract":"\u0000 The dispersion characteristics of airborne pathogens were investigated in a Boeing 767 mockup cabin containing 11 rows with 7 seats per row, using two tracer gas source methods: continuous injection at low velocity and a coughing manikin. Both the injection source and the coughing manikin were located on the same seat in the sixth row. The injection source utilized CO2 gas at an injection rate of 5.0 liters per minute mixed with helium at a rate of 3.07 liters per minute to neutralize buoyancy. The manikin coughed approximately once every 75 seconds, with a volume of 4.2 liters of CO2 per cough. To ensure sufficient data were collected at each sampling location, each coughing manikin test was run for 6 coughs and each injection source test for 30 minutes of continuous injection. In both test methods, the tracer gas concentration was measured using CO2 gas analyzers at seated passenger breathing height of 1.2 m and radially up to 3.35 m away from the gas injection location, representing approximately four rows of a standard B767 aircraft. The collected data obtained from each tracer method was then normalized to provide a suitable comparison basis that is independent of tracer gas introduction flowrate. The results showed that both tracer source methods gave similar dispersion trends in diagonal and lateral directions away from the injection location. However, the tracer gas concentration was higher along the longitudinal direction in the coughing manikin tests due to the cough momentum. The results of this work will help researchers analyze different experimental and numerical approaches used to determine contaminant dispersion in various environments and will provide a better understanding of the associated transport phenomena.","PeriodicalId":103887,"journal":{"name":"Volume 1: Fluid Applications and Systems; Fluid Measurement and Instrumentation","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131689234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we present an experimental and numerical study in a horizontal duct with a rectangular cross-section (300 × 30mm2). In the middle of this cross-section, a rectangular obstacle (20 × 10mm2) then a squared obstacle (10 × 10mm2) were placed in order to study experimentally and numerically the vortex shedding and their interactions in the flow. Upstream obstacles, the studied flows are laminar. In our experimental study, the PIV technique was used in order to obtain instantaneous velocity fields downstream the used obstacles. From these measurement results, a post-processing was used (especially the Γ2 criterion) in order to well extract instantaneous vortices contained in the flow downstream obstacles. In parallel with this experimental study, a 2D numerical simulation was achieved in order to be validated by the experimental results. Other complementary PIV measurements were carried out in the duct top by visualizing the flow downstream obstacles in order to study the 3D effects of the flow.
{"title":"Experimental and Numerical Investigations of Unsteady Flows Downstream Confined Rectangular Obstacles","authors":"F. Aloui, A. Elawady","doi":"10.1115/fedsm2020-20322","DOIUrl":"https://doi.org/10.1115/fedsm2020-20322","url":null,"abstract":"\u0000 In this work, we present an experimental and numerical study in a horizontal duct with a rectangular cross-section (300 × 30mm2). In the middle of this cross-section, a rectangular obstacle (20 × 10mm2) then a squared obstacle (10 × 10mm2) were placed in order to study experimentally and numerically the vortex shedding and their interactions in the flow. Upstream obstacles, the studied flows are laminar. In our experimental study, the PIV technique was used in order to obtain instantaneous velocity fields downstream the used obstacles. From these measurement results, a post-processing was used (especially the Γ2 criterion) in order to well extract instantaneous vortices contained in the flow downstream obstacles. In parallel with this experimental study, a 2D numerical simulation was achieved in order to be validated by the experimental results. Other complementary PIV measurements were carried out in the duct top by visualizing the flow downstream obstacles in order to study the 3D effects of the flow.","PeriodicalId":103887,"journal":{"name":"Volume 1: Fluid Applications and Systems; Fluid Measurement and Instrumentation","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124986279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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