Experimental Study of Incompressible Jets with Different Initial Swirl Distribution
Author : Robert Treat Gilchrist
Publisher :
Page : 196 pages
File Size : 11,94 MB
Release : 2005
Category : Jets
ISBN :
Author : Robert Treat Gilchrist
Publisher :
Page : 196 pages
File Size : 11,94 MB
Release : 2005
Category : Jets
ISBN :
Author : Jonathan Wayne Naughton
Publisher :
Page : 30 pages
File Size : 45,51 MB
Release : 2009
Category : Eddies
ISBN :
Swirling jet flows have been studied experimentally and computationally and the results have been compared with theory. Three-component Laser Doppler Anemometry (LDA) measurements have been carried out for swirling jets of various strengths and swirl distributions. Radial profiles of velocity have been obtained from the jet exit to 50 diameters downstream. The experimental results are consistent with previous results and with similarity theory for weakly swirling turbulent jets. However, the parametric range and spatial domain of the current data set makes it suitable for validation. Computational simulations have also been performed using a combination of Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches. The results have been validated with experimental data and used to explore the mechanisms behind the increased mixing enhancement observed. The combined experimental/computational effort is still ongoing, but the experiences to date have demonstrated the effectiveness of such an approach.
Author : R. T. Gilchrist
Publisher :
Page : pages
File Size : 37,67 MB
Release : 2003
Category :
ISBN :
Author : Anjaneyulu Krothapalli
Publisher :
Page : 174 pages
File Size : 17,73 MB
Release : 1979
Category : Air jets
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Author :
Publisher :
Page : 174 pages
File Size : 40,80 MB
Release : 1979
Category :
ISBN :
Author : Illinois. University. Dept. of Aeronautical Engineering
Publisher :
Page : 538 pages
File Size : 15,25 MB
Release : 1955
Category : Laminar flow
ISBN :
Author : Sarah Elizabeth Bingman
Publisher :
Page : 134 pages
File Size : 30,43 MB
Release : 1983
Category :
ISBN :
Author : American Institute of Aeronautics and Astronautics
Publisher :
Page : 530 pages
File Size : 42,16 MB
Release : 2008
Category : Aeronautics
ISBN :
Author : Ing Kiet Francis Toh
Publisher :
Page : 247 pages
File Size : 38,24 MB
Release : 2010
Category : Jets
ISBN :
The mean flow properties and the instantaneous flow structures of the jets are then investigated. The introduction and increase of swirl result in a higher jet growth, decay and turbulent intensity, the formation of an off-axis axial velocity maximum and the occurrence of vortex breakdown. The swirl-induced jet growth enhancement can be categorized into three regimes: a low swirl regime in which there is a limited enhancement, a moderate swirl regime in which the enhancement scales with swirl, and a high swirl regime in which vortex breakdown dominates the process. The jet growth behavior in the high swirl regime is found to be dependent on the structure of the jet and the vortex breakdown configuration. A significant change in the flow structures and certain mean flow properties including the centerline and local maximum axial velocity decay are observed in the low and the moderate swirl regimes. These properties appear to be less sensitive to swirl in the high swirl regime after the occurrence of vortex breakdown. The effects of Reynolds number on swirling jets may not be identical to that on a non-swirling jet. The statistical characteristics measured show that low velocity occasions in the vicinity of the jet centerline start to appear at a sufficiently high degree of swirl. These occasions increase with swirl until the eventual occurrence of vortex breakdown. The statistical characteristics of jets that have undergone vortex breakdown are very similar, as they are dominated by the vortex breakdown phenomenon. The mean flow and the statistical measurements also reveal the presence of an unstable vortex breakdown that is difficult to detect using flow visualization and instantanous velocity field measurements.
Author : Ronald M. C. So
Publisher :
Page : 158 pages
File Size : 26,55 MB
Release : 1984
Category : Combustion engineering
ISBN :