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Large Eddy Simulation Of Liquid Jet Primary Breakup
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Book Synopsis Large Eddy Simulation of Liquid Jet Primary Breakup by : Feng Xiao
Download or read book Large Eddy Simulation of Liquid Jet Primary Breakup written by Feng Xiao and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomisation of liquid fuel jets is an important determinant of combustion performance in gas turbine engines, and thus is the prime research driver here. Since the first stage of the atomisation process primary breakup has not been well understood due to its complexity, the objective of the current project is to develop a robust algorithm for Large Eddy Simulation (LES) to predict primary breakup. In order to provide realistic turbulent inflows for LES of liquid jet primary breakup, a rescaling/recycling method has been developed and validated. Three interface capturing ethods, namely Level Set (LS), Volume of Fluid (VOF), and coupled Level Set and VOF (CLSVOF), have been implemented and evaluated. The CLSVOF technique is adopted as the interface-tracking method in order to combine the advantages of LS and VOF methods. Due to the discontinuity of density and viscosity across the interface, simulations can become unstable due to numerical errors when a conventional discretisation approach is applied. Therefore, the governing equations are discretised here by introducing an extrapolated liquid velocity to minimise the interface momentum error, showing significant improvement in accuracy and robustness for simulations of primary breakup. For several reasons, single drop breakup in a uniform air flow is chosen as a benchmark test case for validation of the developed methodology for modelling atomisation. It is shown that the predicted drop breakup agrees quantitatively well with experiments for different Weber numbers. The solver is then applied to simulate primary breakup of liquid jets, which are more relevant to industrial applications. By simulating single round water jet atomisation in high-speed coaxial air flow, it is found that the predicted liquid core breakup lengths at different air/liquid velocities agree closely with measured data, but only when appropriate turbulent inflow conditions are specified. In simulations of liquid jet breakup in air crossflow, the penetration of the liquid jet is also well reproduced when turbulent inflows are used. In both simulations, it is found that the turbulence convected downstream from the injection nozzles affects significantly the primary breakup process, and the liquid turbulence rather than the gas turbulence plays a dominant role in initial disturbance of the liquid jet surface.
Book Synopsis Large Eddy Simulation of Primary Liquid-sheet Breakup by : Thibault Roland Christophe Maurice Pringuey
Download or read book Large Eddy Simulation of Primary Liquid-sheet Breakup written by Thibault Roland Christophe Maurice Pringuey and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research project aims at providing the aeronautical industry with a modelling capability to simulate the fuel injection in gas turbine combustion chambers. The path to this objective started with the review of state-of-the-art numerical techniques to model the primary breakup of liquid fuel into droplets. Based on this and keeping in mind the requirements of the industry, our modelling strategy led to the generation of a mass-conservative method for efficient atomisation modelling on unstructured meshes. This goal has been reached with the creation of high-order numerical schemes for unstructured grids, the development of an efficient numerical method that transports the liquid-vapour interface accurately while conserving mass and the implementation of an algorithm that outputs the droplet boundary conditions to separate combustion codes. Both high-order linear and WENO schemes have been created for general polyhedral meshes. The notorious complexity of high-order schemes on 3D mixed-element meshes has been handled by the creation of a series of algorithms. These include the tetrahedralisation of the mesh, which allows generality of the approach while remaining efficient and affordable, together with a novel approach to stencil generation and a faster interpolation of the solution. The performance of the scheme has been demonstrated on typical two-dimensional and three-dimensional test cases for both linear and non-linear hyperbolic partial differential equations. The conservative level set method has been extended to unstructured meshes and its performance has been improved in terms of robustness and accuracy. This was achieved by solving the equations for the transport of the liquid volume fraction with our novel WENO scheme for polyhedral meshes and by adding a flux-limiter algorithm. The resulting method, named robust conservative level set, conserves mass to machine accuracy and its ability to capture the physics of the atomisation is demonstrated in this thesis. To be readily applicable to the simulation of atomisation, the novel interfacecapturing technique has been embedded in a framework - within the open source CFD code OpenFOAM - that solves the velocity and pressure fields, outputs droplet characteristics and runs in parallel. In particular, the production of droplet boundary conditions involves a set of routines handling the selection of drops in the level set field, the calculation of relevant droplet characteristics and their storage into data files. An n-halo parallelisation method has been implemented in OpenFOAM to perform the computations at the expected order of accuracy. Finally, the modelling capability has been demonstrated on the simulation of primary liquid-sheet breakup with relevance to fuel injection in aero-engine combustors. The computation has demonstrated the ability of the code to capture the physics accurately and further illustrates the potential of the numerical approach.
Book Synopsis Direct and Large Eddy Simulation XII by : Manuel García-Villalba
Download or read book Direct and Large Eddy Simulation XII written by Manuel García-Villalba and published by Springer Nature. This book was released on 2020-05-09 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 12th instalment in the bi-annual Workshop series on Direct and Large Eddy Simulation (DLES), which began in 1994 and focuses on modern techniques used to simulate turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structure. With the rapidly expanding capacities of modern computers, this approach has attracted more and more interest over the years and will undoubtedly be further enhanced and applied in the future. Hybrid modelling techniques based on a combination of LES and RANS approaches also fall into this category and are covered as well. The goal of the Workshop was to share the state of the art in DNS, LES and related techniques for the computation and modelling of turbulent and transitional flows. The respective papers highlight the latest advances in the prediction, understanding and control of turbulent flows in academic and industrial applications.
Book Synopsis Jet in Supersonic Crossflow by : Mingbo Sun
Download or read book Jet in Supersonic Crossflow written by Mingbo Sun and published by . This book was released on 2019 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on research into jets in supersonic crossflow carried out by the authors’ team over the past 15 years, this book summarizes and presents many cutting-edge findings and analyses on this subject. It tackles the complicated mixing process of gas jets and atomization process of liquid jets in supersonic crossflow, and studies their physical mechanisms. Advanced experimental and numerical techniques are applied to further readers’ understanding of atomization, mixing, and combustion of fuel jets in supersonic crossflow, which can promote superior fuel injection design in scramjet engines. The book offers a valuable reference guide for all researchers and engineers working on the design of scramjet engines, and will also benefit graduate students majoring in aeronautical and aerospace engineering.
Book Synopsis Large Eddy Simulation of Two-phase Flows from the Intact Liquid Jet to the Dilute Spray Regime by : Holger Grosshans
Download or read book Large Eddy Simulation of Two-phase Flows from the Intact Liquid Jet to the Dilute Spray Regime written by Holger Grosshans and published by . This book was released on 2011 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Internal Combustion Processes of Liquid Rocket Engines by : Zhen-Guo Wang
Download or read book Internal Combustion Processes of Liquid Rocket Engines written by Zhen-Guo Wang and published by John Wiley & Sons. This book was released on 2016-05-17 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concentrates on modeling and numerical simulations of combustion in liquid rocket engines, covering liquid propellant atomization, evaporation of liquid droplets, turbulent flows, turbulent combustion, heat transfer, and combustion instability. It presents some state of the art models and numerical methodologies in this area. The book can be categorized into two parts. Part 1 describes the modeling for each subtopic of the combustion process in the liquid rocket engines. Part 2 presents detailed numerical methodology and several representative applications in simulations of rocket engine combustion.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781719484084 Total Pages :90 pages Book Rating :4.4/5 (84 download)
Book Synopsis Modeling of Turbulence Effect on Liquid Jet Atomization by : National Aeronautics and Space Administration (NASA)
Download or read book Modeling of Turbulence Effect on Liquid Jet Atomization written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies indicate that turbulence behaviors within a liquid jet have considerable effect on the atomization process. Such turbulent flow phenomena are encountered in most practical applications of common liquid spray devices. This research aims to model the effects of turbulence occurring inside a cylindrical liquid jet to its atomization process. The two widely used atomization models Kelvin-Helmholtz (KH) instability of Reitz and the Taylor analogy breakup (TAB) of O'Rourke and Amsden portraying primary liquid jet disintegration and secondary droplet breakup, respectively, are examined. Additional terms are formulated and appropriately implemented into these two models to account for the turbulence effect. Results for the flow conditions examined in this study indicate that the turbulence terms are significant in comparison with other terms in the models. In the primary breakup regime, the turbulent liquid jet tends to break up into large drops while its intact core is slightly shorter than those without turbulence. In contrast, the secondary droplet breakup with the inside liquid turbulence consideration produces smaller drops. Computational results indicate that the proposed models provide predictions that agree reasonably well with available measured data. Trinh, H. P. Marshall Space Flight Center TURBULENCE EFFECTS; MATHEMATICAL MODELS; COMPUTATIONAL FLUID DYNAMICS; LIQUID ATOMIZATION; TURBULENT FLOW; JET FLOW; KELVIN-HELMHOLTZ INSTABILITY; DIRECT NUMERICAL SIMULATION; LARGE EDDY SIMULATION; DROP SIZE; SPRAYERS; TURBULENT JETS; DISINTEGRATION
Book Synopsis Jet in Supersonic Crossflow by : Mingbo Sun
Download or read book Jet in Supersonic Crossflow written by Mingbo Sun and published by Springer. This book was released on 2019-02-18 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on research into jets in supersonic crossflow carried out by the authors’ team over the past 15 years, this book summarizes and presents many cutting-edge findings and analyses on this subject. It tackles the complicated mixing process of gas jets and atomization process of liquid jets in supersonic crossflow, and studies their physical mechanisms. Advanced experimental and numerical techniques are applied to further readers’ understanding of atomization, mixing, and combustion of fuel jets in supersonic crossflow, which can promote superior fuel injection design in scramjet engines. The book offers a valuable reference guide for all researchers and engineers working on the design of scramjet engines, and will also benefit graduate students majoring in aeronautical and aerospace engineering.
Book Synopsis Direct and Large-Eddy Simulation X by : Dimokratis G.E. Grigoriadis
Download or read book Direct and Large-Eddy Simulation X written by Dimokratis G.E. Grigoriadis and published by Springer. This book was released on 2017-10-06 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses nearly all aspects of the state of the art in LES & DNS of turbulent flows, ranging from flows in biological systems and the environment to external aerodynamics, domestic and centralized energy production, combustion, propulsion as well as applications of industrial interest. Following the advances in increased computational power and efficiency, several contributions are devoted to LES & DNS of challenging applications, mainly in the area of turbomachinery, including flame modeling, combustion processes and aeroacoustics. The book includes work presented at the tenth Workshop on 'Direct and Large-Eddy Simulation' (DLES-10), which was hosted in Cyprus by the University of Cyprus, from May 27 to 29, 2015. The goal of the workshop was to establish a state of the art in DNS, LES and related techniques for the computation and modeling of turbulent and transitional flows. The book is of interest to scientists and engineers, both in the early stages of their career and at a more senior level.
Book Synopsis Direct and Large-Eddy Simulation XI by : Maria Vittoria Salvetti
Download or read book Direct and Large-Eddy Simulation XI written by Maria Vittoria Salvetti and published by Springer. This book was released on 2019-02-02 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 11th workshop on Direct and Large Eddy Simulation (DLES), which was held in Pisa, Italy in May 2017. The event focused on modern techniques for simulating turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structures, as Direct Numerical Simulation (DNS), Large-Eddy Simulation (LES) or hybrid models based on a combination of LES and RANS approaches. In light of the growing capacities of modern computers, these approaches have been gaining more and more interest over the years and will undoubtedly be developed and applied further. The workshop offered a unique opportunity to establish a state-of-the-art of DNS, LES and related techniques for the computation and modeling of turbulent and transitional flows and to discuss about recent advances and applications. This volume contains most of the contributed papers, which were submitted and further reviewed for publication. They cover advances in computational techniques, SGS modeling, boundary conditions, post-processing and data analysis, and applications in several fields, namely multiphase and reactive flows, convection and heat transfer, compressible flows, aerodynamics of airfoils and wings, bluff-body and separated flows, internal flows and wall turbulence and other complex flows.
Book Synopsis Direct and Large-Eddy Simulation I by : Peter R. Voke
Download or read book Direct and Large-Eddy Simulation I written by Peter R. Voke and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is a truism that turbulence is an unsolved problem, whether in scientific, engin eering or geophysical terms. It is strange that this remains largely the case even though we now know how to solve directly, with the help of sufficiently large and powerful computers, accurate approximations to the equations that govern tur bulent flows. The problem lies not with our numerical approximations but with the size of the computational task and the complexity of the solutions we gen erate, which match the complexity of real turbulence precisely in so far as the computations mimic the real flows. The fact that we can now solve some turbu lence in this limited sense is nevertheless an enormous step towards the goal of full understanding. Direct and large-eddy simulations are these numerical solutions of turbulence. They reproduce with remarkable fidelity the statistical, structural and dynamical properties of physical turbulent and transitional flows, though since the simula tions are necessarily time-dependent and three-dimensional they demand the most advanced computer resources at our disposal. The numerical techniques vary from accurate spectral methods and high-order finite differences to simple finite-volume algorithms derived on the principle of embedding fundamental conservation prop erties in the numerical operations. Genuine direct simulations resolve all the fluid motions fully, and require the highest practical accuracy in their numerical and temporal discretisation. Such simulations have the virtue of great fidelity when carried out carefully, and repre sent a most powerful tool for investigating the processes of transition to turbulence.
Book Synopsis Direct and Large-Eddy Simulation VIII by : Hans Kuerten
Download or read book Direct and Large-Eddy Simulation VIII written by Hans Kuerten and published by Springer Science & Business Media. This book was released on 2011-10-05 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume continues previous DLES proceedings books, presenting modern developments in turbulent flow research. It is comprehensive in its coverage of numerical and modeling techniques for fluid mechanics. After Surrey in 1994, Grenoble in 1996, Cambridge in 1999, Enschede in 2001, Munich in 2003, Poitiers in 2005, and Trieste in 2009, the 8th workshop, DLES8, was held in Eindhoven, The Netherlands, again under the auspices of ERCOFTAC. Following the spirit of the series, the goal of this workshop is to establish a state-of-the-art of DNS and LES techniques for the computation and modeling of transitional/turbulent flows covering a broad scope of topics such as aerodynamics, acoustics, combustion, multiphase flows, environment, geophysics and bio-medical applications. This gathering of specialists in the field was a unique opportunity for discussions about the more recent advances in the prediction, understanding and control of turbulent flows in academic or industrial situations.
Book Synopsis Large Eddy Simulation for Incompressible Flows by : P. Sagaut
Download or read book Large Eddy Simulation for Incompressible Flows written by P. Sagaut and published by Springer Science & Business Media. This book was released on 2006 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: First concise textbook on Large-Eddy Simulation, a very important method in scientific computing and engineering From the foreword to the third edition written by Charles Meneveau: "... this meticulously assembled and significantly enlarged description of the many aspects of LES will be a most welcome addition to the bookshelves of scientists and engineers in fluid mechanics, LES practitioners, and students of turbulence in general."
Book Synopsis Quality and Reliability of Large-Eddy Simulations by : Johan Meyers
Download or read book Quality and Reliability of Large-Eddy Simulations written by Johan Meyers and published by Springer Science & Business Media. This book was released on 2008-06-26 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational resources have developed to the level that, for the first time, it is becoming possible to apply large-eddy simulation (LES) to turbulent flow problems of realistic complexity. Many examples can be found in technology and in a variety of natural flows. This puts issues related to assessing, assuring, and predicting the quality of LES into the spotlight. Several LES studies have been published in the past, demonstrating a high level of accuracy with which turbulent flow predictions can be attained, without having to resort to the excessive requirements on computational resources imposed by direct numerical simulations. However, the setup and use of turbulent flow simulations requires a profound knowledge of fluid mechanics, numerical techniques, and the application under consideration. The susceptibility of large-eddy simulations to errors in modelling, in numerics, and in the treatment of boundary conditions, can be quite large due to nonlinear accumulation of different contributions over time, leading to an intricate and unpredictable situation. A full understanding of the interacting error dynamics in large-eddy simulations is still lacking. To ensure the reliability of large-eddy simulations for a wide range of industrial users, the development of clear standards for the evaluation, prediction, and control of simulation errors in LES is summoned. The workshop on Quality and Reliability of Large-Eddy Simulations, held October 22-24, 2007 in Leuven, Belgium (QLES2007), provided one of the first platforms specifically addressing these aspects of LES.
Book Synopsis Modeling and Simulation of Turbulent Mixing and Reaction by : Daniel Livescu
Download or read book Modeling and Simulation of Turbulent Mixing and Reaction written by Daniel Livescu and published by Springer Nature. This book was released on 2020-02-19 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights recent research advances in the area of turbulent flows from both industry and academia for applications in the area of Aerospace and Mechanical engineering. Contributions include modeling, simulations and experiments meant for researchers, professionals and students in the area.
Book Synopsis Large-Eddy Simulations of Turbulence by : M. Lesieur
Download or read book Large-Eddy Simulations of Turbulence written by M. Lesieur and published by Cambridge University Press. This book was released on 2005-08-22 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-Eddy Simulations of Turbulence is a reference for LES, direct numerical simulation and Reynolds-averaged Navier-Stokes simulation.
Book Synopsis Handbook of Atomization and Sprays by : Nasser Ashgriz
Download or read book Handbook of Atomization and Sprays written by Nasser Ashgriz and published by Springer Science & Business Media. This book was released on 2011-02-18 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization and sprays are used in a wide range of industries: mechanical, chemical, aerospace, and civil engineering; material science and metallurgy; food; pharmaceutical, forestry, environmental protection; medicine; agriculture; meteorology and others. Some specific applications are spray combustion in furnaces, gas turbines and rockets, spray drying and cooling, air conditioning, powdered metallurgy, spray painting and coating, inhalation therapy, and many others. The Handbook of Atomization and Sprays will bring together the fundamental and applied material from all fields into one comprehensive source. Subject areas included in the reference are droplets, theoretical models and numerical simulations, phase Doppler particle analysis, applications, devices and more.
