Author: Publisher:
ISBN:
Category : Jets
Languages : en
Pages : 398
Book Description
Turbulent Mixing in Free Swirling Jets
Author: Integrated Computational/experimental Study of Turbulence Modification and Mixing Enhancement in Swirling Jets
Author: Jonathan Wayne NaughtonPublisher:
ISBN:
Category : Eddies
Languages : en
Pages : 30
Book Description
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.
Some Effects of Swirl on Turbulent Mixing and Combustion
Author: Arthur RubelPublisher:
ISBN:
Category : Combustion
Languages : en
Pages : 68
Book Description
Analysis of Swirling Jet Turbulent Mixing and Combustion
Author: Jean Pascal SislianPublisher:
ISBN:
Category : Combustion
Languages : en
Pages : 33
Book Description
Interaction of a Swirling Jet with a Free Surface
Author: Michael S. FeyedelemPublisher:
ISBN:
Category :
Languages : en
Pages : 175
Book Description
The turbulent flow field of a swirling jet issuing from a nozzle, beneath and parallel to a free surface has been studied in as much detail as possible using a three-component laser Doppler velocimeter and flow visualization. The results have shown that the swirl leads to the faster spreading and quicker mixing of the jet. For strongly swirling jets (S = 0.522), the similiarity is not reached within ten diameters downstream. The results have also shown that both the acial and tangential velocity components decrease outward from the jet axis, naturall leading to centrifugal instabilities. This, in turn, leads to the creation of large scale coherent structures at the periphery of the jet, particularly when it is in the vicinity of the free surface. The turbulent shear stresses exhibit anisotropic behavior, the largest always being in the plane passing through the jet axis. The change of TKE with S is not monotonic. It is maximum for S - 0.265, smallest for S = 0.50, and has an intermediate value for S - 0.522. This is due to the occurrence of vortex breakdown and the resulting intensification of the turbulence within the jet prior to its exit from the nozzle.
Swirling Jet Turbulent Mixing and Combustion Computations
Author: Arthur RubelPublisher:
ISBN:
Category : Combustion
Languages : en
Pages : 50
Book Description
Interation of a Swirling Jet with a Free Surface
Author: Michael S. FeyedelemPublisher:
ISBN: 9781423575979
Category :
Languages : en
Pages : 198
Book Description
The turbulent flow field of a swirling jet issuing from a nozzle, beneath and parallel to a free surface has been studied in as much detail as possible using a three-component laser Doppler velocimeter and flow visualization. The results have shown that the swirl leads to the faster spreading and quicker mixing of the jet. For strongly swirling jets (S = 0.522), the similarity is not reached within ten diameters downstream. The results have also shown that both the axial and tangential velocity components decrease outward from the jet axis, naturally leading to centrifugal instabilities. This, in turn, leads to the creation of large scale coherent structures at the periphery of the jet, particularly when it is in the vicinity of the free surface. The turbulent shear stresses exhibit anisotropic behavior, the largest always being in the plane passing through the jet axis. The change of TKE with S is not monotonic. It is maximum for S = 0.265, smallest for S = 0.50, and has an intermediate value for S = 0.522. This is due to the occurrence of vortex breakdown and the resulting intensification of the turbulence within the jet prior to its exit from the nozzle.
Turbulent Mixing in Swirling Flow
Author: Wai Kong ChengPublisher:
ISBN:
Category : Mixing
Languages : en
Pages : 186
Book Description
Determination and Correlation of Turbulent Mixing Parameters in Free and Confined Jets
Author: Dennis Earl StowellPublisher:
ISBN:
Category : Jets
Languages : en
Pages : 278
Book Description
Turbulent Flows
Author: Jean PiquetPublisher: Springer Science & Business Media
ISBN: 3662035596
Category : Technology & Engineering
Languages : en
Pages : 767
Book Description
obtained are still severely limited to low Reynolds numbers (about only one decade better than direct numerical simulations), and the interpretation of such calculations for complex, curved geometries is still unclear. It is evident that a lot of work (and a very significant increase in available computing power) is required before such methods can be adopted in daily's engineering practice. I hope to l"Cport on all these topics in a near future. The book is divided into six chapters, each· chapter in subchapters, sections and subsections. The first part is introduced by Chapter 1 which summarizes the equations of fluid mechanies, it is developed in C~apters 2 to 4 devoted to the construction of turbulence models. What has been called "engineering methods" is considered in Chapter 2 where the Reynolds averaged equations al"C established and the closure problem studied (§1-3). A first detailed study of homogeneous turbulent flows follows (§4). It includes a review of available experimental data and their modeling. The eddy viscosity concept is analyzed in §5 with the l"Csulting ~alar-transport equation models such as the famous K-e model. Reynolds stl"Css models (Chapter 4) require a preliminary consideration of two-point turbulence concepts which are developed in Chapter 3 devoted to homogeneous turbulence. We review the two-point moments of velocity fields and their spectral transforms (§ 1), their general dynamics (§2) with the particular case of homogeneous, isotropie turbulence (§3) whel"C the so-called Kolmogorov's assumptions are discussed at length.