The Fluid Mechanics of Swirling Flow Within Annular Regions

The Fluid Mechanics of Swirling Flow Within Annular Regions PDF Author: Robert Milano
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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The Fluid Mechanics of Swirling Flow Within Annular Regions

The Fluid Mechanics of Swirling Flow Within Annular Regions PDF Author: Robert Milano
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Unsteady Fluid Mechanics of Annular Swirling Shear Layers

Unsteady Fluid Mechanics of Annular Swirling Shear Layers PDF Author: David Dunham
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The vast majority of gas turbine combustor systems employ swirl injectors to produce a central toroidal recirculation zone (CTRZ) which entrains and recirculates a portion of the hot combustion gases to provide continuous ignition to the incoming air-fuel mix. In addition to these primary functions, swirl injectors often generate multiple aerodynamic instability modes which are helical in nature with characteristic frequencies that can differ by many orders of magnitude. If any of these frequencies are consistent with prevalent acoustic modes within the combustor there is a potential for flow-acoustic coupling which may reinforce acoustic oscillations and drive combustion instabilities via the Rayleigh criterion. The aerodynamic performance of the swirl injector is thus of great practical importance to the design and development of combustion systems and there is a strong desire within industry for reliable computational methods that can predict this highly unsteady behaviour. This assessment can be made under isothermal conditions which avoids the complex interactions that occur in reacting flow. The goal of the present work was to compare and contrast the performance of Unsteady Reynolds- Averaged Navier-Stokes (URANS) and Large-Eddy Simulation (LES) CFD methodologies for a combustion system equipped with a derivative of an industrial Turbomeca swirl injector as this exhibits similar unsteady aerodynamic behaviour under reacting and isothermal conditions. The influence of the level of swirl, SN = 0.51-0.8, was first investigated experimentally using Particle Image Velocimetry (PIV) by varying the inlet swirl vane angle. Based on a qualitative assessment of instantaneous velocity data, and a range of coherent structure eduction techniques, it was found that ®1 = 30± (SN 1/4 0.8) would be the most challenging test case for LES and URANS as this contained near and far-field instability modes that differ in frequency by around two orders of magnitude and the highest levels of normal Reynolds-stress anisotropy. Based on extensive simulations performed with both in-house (LULES and Delta) and commercial (Fluent) CFD codes it was found that, despite the relative modest computational cost of URANS which is between one-third (RST) to an order of magnitude (k-2) less than that demanded by LES, only LES captures the all-important frequency content in accordance with experimental evidence and, thus, only LES can be recommended for use in swirl injector flows. The increased cost is believed to be an absolutely worthwhile expense because of the high fidelity of the predicted results in the important area of flow instabilities.

Cellular Flows

Cellular Flows PDF Author: Vladimir Shtern
Publisher: Cambridge University Press
ISBN: 110831421X
Category : Technology & Engineering
Languages : en
Pages : 590

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Book Description
A cell, whose spatial extent is small compared with a surrounding flow, can develop inside a vortex. Such cells, often referred to as vortex breakdown bubbles, provide stable and clean flame in combustion chambers; they also reduce the lift force of delta wings. This book analyzes cells in slow and fast, one- and two-fluid flows and describes the mechanisms of cell generation: (a) minimal energy dissipation, (b) competing forces, (c) jet entrainment, and (d) swirl decay. The book explains the vortex breakdown appearance, discusses its features, and indicates means of its control. Written in acceptable, non-math-heavy format, it stands to be a useful learning tool for engineers working with combustion chambers, chemical and biological reactors, and delta-wing designs.

Fluid Mechanics

Fluid Mechanics PDF Author: Bijay Sultanian
Publisher: CRC Press
ISBN: 1466598999
Category : Technology & Engineering
Languages : en
Pages : 570

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Book Description
Fluid Mechanics: An Intermediate Approach addresses the problems facing engineers today by taking on practical, rather than theoretical problems. Instead of following an approach that focuses on mathematics first, this book allows you to develop an intuitive physical understanding of various fluid flows, including internal compressible flows with s

Swirl Flows

Swirl Flows PDF Author: Ashwani K. Gupta
Publisher: Routledge
ISBN:
Category : Science
Languages : en
Pages : 496

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New Results in Numerical and Experimental Fluid Mechanics VI

New Results in Numerical and Experimental Fluid Mechanics VI PDF Author: Cameron Tropea
Publisher: Springer Science & Business Media
ISBN: 3540744584
Category : Computers
Languages : en
Pages : 973

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Book Description
This volume features the contributions to the 15th Symposium of the STAB (German Aerospace Aerodynamics Association). Papers provide a broad overview of ongoing work in Germany, including high aspect ratio wings, low aspect ratio wings, bluff bodies, laminar flow control and transition, active flow control, hypersonic flows, aeroelasticity, aeroacoustics, mathematical fundamentals, numerical simulations, physical fundamentals, and facilities.

The Seventh Asian Congress of Fluid Mechanics

The Seventh Asian Congress of Fluid Mechanics PDF Author:
Publisher: Allied Publishers
ISBN: 9788170237327
Category : Fluid mechanics
Languages : en
Pages : 486

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Fluid Mechanics and Fluid Power (Vol. 3)

Fluid Mechanics and Fluid Power (Vol. 3) PDF Author: Suvanjan Bhattacharyya
Publisher: Springer Nature
ISBN: 9811962707
Category : Science
Languages : en
Pages : 628

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Book Description
This book presents the select proceedings of the 48th National Conference on Fluid Mechanics and Fluid Power (FMFP 2021) held at BITS Pilani in December 2021. It covers the topics such as fluid mechanics, measurement techniques in fluid flows, computational fluid dynamics, instability, transition and turbulence, fluid‐structure interaction, multiphase flows, micro- and nanoscale transport, bio-fluid mechanics, aerodynamics, turbomachinery, propulsion and power. The book will be useful for researchers and professionals interested in the broad field of mechanics.

Annular Two-Phase Flow

Annular Two-Phase Flow PDF Author: Geoffrey Hewitt
Publisher: Elsevier
ISBN: 1483285235
Category : Technology & Engineering
Languages : en
Pages : 327

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Book Description
Annular Two-Phase Flow presents the wide range of industrial applications of annular two-phase flow regimes. This book discusses the fluid dynamics and heat transfer aspects of the flow pattern. Organized into 12 chapters, this book begins with an overview of the classification of the various types of interface distribution observed in practice. This text then examines the various regimes of two-phase flow with emphasis on the regions of occurrence of the annular flow regime. Other chapters consider the single momentum and energy balances, which illustrate the differences and analogies between single- and two-phase flows. This book discusses as well the simple modes for annular flow with consideration to the calculation of the profile of shear stress in the liquid film. The final chapter deals with the techniques that are developed for the measurement of flow pattern, entrainment, and film thickness. This book is a valuable resource for chemical engineers.

Applications of Laser Techniques to Fluid Mechanics

Applications of Laser Techniques to Fluid Mechanics PDF Author: R.J. Adrian
Publisher: Springer Science & Business Media
ISBN: 3642612547
Category : Technology & Engineering
Languages : en
Pages : 570

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Book Description
This volume consists of papers selected from the proceedings of the Fifth International Symposium on Applications of Laser Techniques to Fluid Mechanics, held at the Calouste Gulbenkian Foundation in Lisbon from 9 to 12 July, 1990. Relative to previous meetings in the Lisbon series the scope of this symposium was broadened by expanding the topical coverage to include all laser techniques used in fluid mechanics. This change recognized the trend amongst experimental fluid dynamicists to employ laser techniques for the mea surement of many different quantities, including concentration, temperature, particle size, and velocity, and the need for researchers to have a forum in which to communicate their work and share their common interests. The Fifth Symposium contained twenty-three sessions of formal presentations and a lively Open Forum ses sion. In addition, Dr. H. J. Pfeiffer organized a special Workshop on the Use of Computers in Flow Mea surements which contained five sessions on frequency domain processors, correIa tors, special detectors, and biasing.