Author: William M. Pitts
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
Reynolds Number Effects on the Mixing Behavior of Axisymmetric Turbulent Jets
Author: William M. Pitts
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
Effects of Global Density Ratio on the Centerline Mixing Behavior of Axisymmetric Turbulent Jets
Author: William M. Pitts
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
Effects of Global Density and Reynolds Number Variations on Mixing in Turbulent, Axisymmetric Jets
Author: William M. Pitts
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 160
Book Description
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 160
Book Description
Scaling of the Center-line Mixing Behavior in the Near Field of Axisymmetric Turbulent Jets
Author: George Papadopoulos
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Scaling the Near-Field Centerline Mixing Behavior of Axisymmetric Turbulent Jets
Author: G. Papadopoulos
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Effects of Turbulent Mixing on Chemical Reaction in an Aerosol-producing Co-flow Jet
Author: Thomas Paris Jenkins
Publisher:
ISBN:
Category : Aerosols
Languages : en
Pages : 580
Book Description
Investigates the effects of mixing on chemical reaction in a turbulent co-flow jet. After a jet is produced by a mixture of HCl (hydrogen chloride), air, and N2 (nitrogen) issuing from a pipe into a co-flowing stream of NH3 (gaseous ammonia) and air, a chemical reaction in which NH4Cl (ammonium chloride) aerosol with negligible heat release is produced. The product concentration field as marked by the aerosol is then characterized through the collection of data from which probability density functions can be constructed.
Publisher:
ISBN:
Category : Aerosols
Languages : en
Pages : 580
Book Description
Investigates the effects of mixing on chemical reaction in a turbulent co-flow jet. After a jet is produced by a mixture of HCl (hydrogen chloride), air, and N2 (nitrogen) issuing from a pipe into a co-flowing stream of NH3 (gaseous ammonia) and air, a chemical reaction in which NH4Cl (ammonium chloride) aerosol with negligible heat release is produced. The product concentration field as marked by the aerosol is then characterized through the collection of data from which probability density functions can be constructed.
Effect of Background Turbulence on the Scalar Field of a Turbulent Jet
Author: Alejandro Perez Alvarado
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
"The effect of background turbulence on the scalar field of an axisymmetric turbulent jet is investigated experimentally. The present investigation builds on the work of Gaskin et al. (2004), who studied the concentration and velocity fields of a plane jet in a shallow coflow with different turbulence levels and Khorsandi et al. (2013), who studied the velocity field of an axisymmetric turbulent jet emitted into a turbulent background. Different driving algorithms for a large RJA were tested and the statistics of the turbulence generated downstream of the RJA were compared to characterize the algorithms' performance. Variations in the spatial configuration of jets operating at any given instant, as well as in the statistics of their on/off times were studied. The algorithm identified as RANDOM generated the closest approximation of zero-mean-flow homogeneous isotropic turbulence. The flow generated by the RANDOM algorithm had a relatively high turbulent Reynolds number (ReT = uTl/[nu] = 2360, where uT is a characteristic RMS velocity, l is the integral length scale of the flow, [nu] is the kinematic viscosity of the water) and the integral length scale (l = 11.6 cm) is the largest reported to date. Thus, RANDOM algorithm was used to generate the background turbulence for the investigation of scalar mixing within a turbulent jet.The effect of background turbulence on the mixing of a passive scalar within a turbulent jet at different Reynolds numbers was investigated. To this end, planar laser-induced fluorescence was employed to obtain concentration measurements of dye (disodium fluorescein, Schmidt number = 2000) within the jet. Two jet Reynolds numbers (Re=UjD/[nu], where Uj is the jet exit velocity, D is the nozzle diameter and [nu] is the kinematic viscosity of the jet fluid, water) were studied: 10600 and 5800. The resulting statistics of the scalar fields showed that the mean concentrations of jets emitted into turbulent backgrounds were lower than those of jets emitted into a quiescent background near the centerline. However, near the edges of the jet (r/x>0.15), the concentrations were higher for the jets issued into turbulent surroundings. The RMS concentrations of the jet emitted into a turbulent background significantly increased. Examination of the probability density functions of concentration revealed a higher degree of intermittency of the scalar field. The probability of low concentrations increased in the presence of background turbulence although the maximum concentrations were comparable to those of the jet emitted into a quiescent background. Flow visualizations revealed meandering of the jet issued into background turbulence, which is associated with the increased probability of lower concentrations and higher intermittency. Additionally, the widths of the jets emitted into a turbulent background were increased. For the lower jet Reynolds number, the described effects were more evident and the jet structure was destroyed by the background turbulence within the measurement region, resulting in flat radial profiles of both the mean and RMS concentrations. Comparison of the results of the scalar field with those of the hydrodynamic jet of Khorsandi et al. (2013) revealed a similar behavior of the two fields. However, the most significant difference was the larger radial extent of the profiles of mean and RMS concentrations, which resulted from the meandering of the jet and increased transport of scalar by turbulent diffusion. The flow visualizations suggest that the entrainment and mixing in the jet in a turbulent background changes with the destruction of jet structure, from jet driven entrainment to become potentially dominated by i) increased lateral advection of the jet by large scales of the background turbulence during the meandering of the jet, which is subsequently mixed by its smaller scales, and ii) turbulent diffusion that is significantly enhanced by the turbulent background." --
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
"The effect of background turbulence on the scalar field of an axisymmetric turbulent jet is investigated experimentally. The present investigation builds on the work of Gaskin et al. (2004), who studied the concentration and velocity fields of a plane jet in a shallow coflow with different turbulence levels and Khorsandi et al. (2013), who studied the velocity field of an axisymmetric turbulent jet emitted into a turbulent background. Different driving algorithms for a large RJA were tested and the statistics of the turbulence generated downstream of the RJA were compared to characterize the algorithms' performance. Variations in the spatial configuration of jets operating at any given instant, as well as in the statistics of their on/off times were studied. The algorithm identified as RANDOM generated the closest approximation of zero-mean-flow homogeneous isotropic turbulence. The flow generated by the RANDOM algorithm had a relatively high turbulent Reynolds number (ReT = uTl/[nu] = 2360, where uT is a characteristic RMS velocity, l is the integral length scale of the flow, [nu] is the kinematic viscosity of the water) and the integral length scale (l = 11.6 cm) is the largest reported to date. Thus, RANDOM algorithm was used to generate the background turbulence for the investigation of scalar mixing within a turbulent jet.The effect of background turbulence on the mixing of a passive scalar within a turbulent jet at different Reynolds numbers was investigated. To this end, planar laser-induced fluorescence was employed to obtain concentration measurements of dye (disodium fluorescein, Schmidt number = 2000) within the jet. Two jet Reynolds numbers (Re=UjD/[nu], where Uj is the jet exit velocity, D is the nozzle diameter and [nu] is the kinematic viscosity of the jet fluid, water) were studied: 10600 and 5800. The resulting statistics of the scalar fields showed that the mean concentrations of jets emitted into turbulent backgrounds were lower than those of jets emitted into a quiescent background near the centerline. However, near the edges of the jet (r/x>0.15), the concentrations were higher for the jets issued into turbulent surroundings. The RMS concentrations of the jet emitted into a turbulent background significantly increased. Examination of the probability density functions of concentration revealed a higher degree of intermittency of the scalar field. The probability of low concentrations increased in the presence of background turbulence although the maximum concentrations were comparable to those of the jet emitted into a quiescent background. Flow visualizations revealed meandering of the jet issued into background turbulence, which is associated with the increased probability of lower concentrations and higher intermittency. Additionally, the widths of the jets emitted into a turbulent background were increased. For the lower jet Reynolds number, the described effects were more evident and the jet structure was destroyed by the background turbulence within the measurement region, resulting in flat radial profiles of both the mean and RMS concentrations. Comparison of the results of the scalar field with those of the hydrodynamic jet of Khorsandi et al. (2013) revealed a similar behavior of the two fields. However, the most significant difference was the larger radial extent of the profiles of mean and RMS concentrations, which resulted from the meandering of the jet and increased transport of scalar by turbulent diffusion. The flow visualizations suggest that the entrainment and mixing in the jet in a turbulent background changes with the destruction of jet structure, from jet driven entrainment to become potentially dominated by i) increased lateral advection of the jet by large scales of the background turbulence during the meandering of the jet, which is subsequently mixed by its smaller scales, and ii) turbulent diffusion that is significantly enhanced by the turbulent background." --
Publications of the National Institute of Standards and Technology ... Catalog
Author: National Institute of Standards and Technology (U.S.)
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 464
Book Description
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 464
Book Description
NIST Building & Fire Research Laboratory Publications
Author:
Publisher:
ISBN:
Category : Building
Languages : en
Pages : 142
Book Description
Publisher:
ISBN:
Category : Building
Languages : en
Pages : 142
Book Description
Mixing of Submerged Turbulent Jets at Low Reynolds Numbers
Author: Christopher D. Ungate
Publisher:
ISBN:
Category : Jets
Languages : en
Pages : 83
Book Description
Publisher:
ISBN:
Category : Jets
Languages : en
Pages : 83
Book Description