Download or read book Development of an Integrated CFD Approach for Internal Nozzle Flows and Sprays written by and published by . This book was released on 2013 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: In modern automotive internal combustion engines the atomization and spraying processes of liquid fuel is an important mechanism by which the fuel is mixed effectively with the combustion chamber gas. The homogeneity of the fuel-air mixture charge and the timing to achieve it affect the characteristics of the subsequent combustion in a number of ways. Experimentalists have found that the atomization process is influenced by the fuel delivery system, specifically, the operating conditions of fuel injection and the internal geometry of the injector nozzles. Therefore, modeling researchers must develop spray models that properly take into account these effects from the injectors. A Computational Fluid Dynamics (CFD) model is developed to simulate internal injector nozzle flows and the external-nozzle atomization and sprays in an integrated way. In light of the continuous nature of the flow within and near the nozzle, an Eulerian flow solver is developed and applied in these regions. This flow solver models compressible two-phase flows with general conservation laws of fluid dynamics. Differences in the thermodynamic states of liquid and gas phases are properly modeled with an Equation of State (EOS). The chosen numerical methods are sufficiently robust to handle pressure and density gradients up to 1000:1 and are able to cover the typical operating ranges of modern diesel and gasoline injection systems. A phase equilibrium model is developed based on the fundamental thermodynamic laws. It is implemented into the Eulerian flow solver to predict phase change in the flows - in particular, the cavitation of liquid fuel within the fuel injector nozzle and how it influences the external flows. A number of test problems are simulated to verify the numerical methods and validate the proposed models. These include two-phase shock tube problems, a shock-interface interaction problem, a converging-diverging nozzle flow problem, and most importantly, high-pressure fuel injection problems. The Eulerian flow solver requires the CFD mesh size to be smaller than the characteristic phase interface length scale in order to apply the continuum fluid assumption. This requirement is challenged beyond a certain distance from the nozzle where the spray is dispersed. Here the mesh size affordable by engineering calculation is too coarse for the Eulerian solver to be applied. At this stage, the Eulerian liquid phase can be transitioned into Lagrangian discrete particles to model the dispersed spray droplets. The modeling of the sub-grid droplet size at this transition stage is based on local balances between turbulent kinetic energy and surface energy. The Eulerian flow solver coupled with the phase equilibrium model and the Eulerian-Lagrangian transition model provides an engineering CFD approach to study the effects of injector nozzle flows on the atomization and sprays.

Download or read book Integrated CFD Modelling for Nozzle Design for Fog Generation written by Yankang Tian and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sprays, as dynamic droplet/particle clouds of functional substances, are widely used in industry, agriculture, and our daily lives. Sprays are different depending on the situations in which they are used and are characterized by pattern, capacity, impact, angle and drop size. Each application has its own requirements for spray characteristics and these requirements are demanding continuing development of atomization systems. Improvement of spraying systems which use a nozzle to convert bulk liquid into dispersed droplets requires knowledge of the atomization process. Although great effort has been dedicated to study, describe, and predict spray generation, flow evolution from continuous stream to separated droplets is still beyond full understanding. What is more, internal nozzle flow and initial breakup that decide the characteristics of far-field spray take place inside enclosed injector, this makes it challenging for non-invasive measurement. At the beginning of this study, available nozzle designs and their performances, and commonly used approaches for modelling fluid flows were reviewed. It is emphasised that there is currently a lack of detailed design principles for sprays with a fine droplet and high flow rate, this type has a great potential for wide application. However, this remains a challenge for advanced nozzle design. To overcome difficulties in the nozzle design, a development workflow is planned in detail. Requirement-oriented nozzle optimization and an integrated CFD model establishment are two closely related components in this study. Numerical results help the justification and dimension selection for nozzle design while physical tests on the nozzle help to validate the CFD model. Architecture for integrated CFD modelling is discussed including the steps for bridging the knowledge gap between different numerical theories. CFD-aided advanced nozzle design and optimization actions are conducted. With parametric modelling a large number of nozzle dimensions can be tested numerically, this largely reduces the development cycle and cost compared to real part fabrication and physical testing. The first detailed design of a nozzle is achieved based on the results from CFD modelling. The designed nozzle was fabricated and then tested in a fog dynamic lab. The results of flow rates, spray angles, and droplet sizes were recorded. These results are used to validate the proposed integrated CFD model. Design of the nozzle was improved by requirement-driven optimization. Virtual testing based on valid integrated CFD modelling is used to study the optimized nozzle design. As an important achievement of this study, a multi-fluid fogging nozzle was designed. Numerical evaluation using integrated CFD modelling shown that the nozzle could generate sprays with flow rate up to 0.53 ?/? and droplets ranging mostly from 2 ?? to 5 ??. The designed nozzle was manufactured and tested in laboratory in Spain. Data obtained from experiments successfully validates the performance predicted by simulations. Being capable to generate spray with high flow rate and fine droplets, this multi-fluid nozzle design shows its strong potential for fogging applications such as firefighting, pest management, and dust suppression.

Download or read book Eulerian CFD Modeling of Multiphase Internal Injector Flow and External Sprays written by Eli T. Baldwin and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The improvement of combustion systems which use sprays to atomize liquid fuel requires an understanding of that atomization process. Although the secondary break up mechanisms for the far-field of an atomizing spray have been thoroughly studied and well understood for some time, understanding the internal nozzle flow and primary atomization on which the far-field spray depends has proven to be more of a challenge. Flow through fuel injector nozzles can be highly complex and heavily influenced by factors such as turbulence, needle motion, nozzle imperfections, nozzle asymmetry, and phase change. All of this occurs within metallic injectors, making experimental characterization challenging. A review of computational studies in literature shows a trend towards engineering models based on the Eulerian description of the fluid, rather than the Lagrangian. With this approach, the internal and external flow can be simulated together. This allows for the influence of nozzle geometry on the spray to be captured. Developments and advancements applicable to these Eulerian solvers are discussed. This includes a new constraint on the turbulent mixing model, as well as the inclusion of a vaporization model and a non-equilibrium phase change model. Additionally, issues regarding thermodynamic and hydrodynamic consistency of compressible flows using a segregated solution approach are addressed, as are issues regarding dynamic mesh motion in a compressible solver. Finally, an efficient way of accounting for high pressure thermodynamic properties is presented. Applied case studies of diesel direct injection are then described. The single-field Eulerian approach is shown to perform very well at the high Reynolds and Weber numbers present in diesel DI conditions, capturing spray characteristics such as density distribution, penetration, and velocity profiles with a moderate level of accuracy. While transient needle motion is shown to cause interesting internal flow features, in converging, axisymmetric diesel DI nozzles, modeling of the internal flow is shown to only marginally benefit the solution. Finally, applied case studies of gasoline direct injection are presented, first with a parameter study varying counterbore depth, pressure drop, and the ambient to saturated pressure ratio. The significant influence of flash-boiling under a low ambient to saturated pressure ratio is shown. Next, a detailed analysis of internal nozzle and near-field flow in flashing and non-flashing multi-hole injection is presented. Excellent agreement to experimental rate of injection is achieved with transient needle motion and qualitative agreement to experimental imaging in the near-field is shown. Complex internal nozzle flow is analyzed and shown to result in string flash-boiling, perturbations and expansions of the spray angle, and oscillation in the ROI. Single-field multiphase Eulerian modeling is a useful tool for understanding and designing DI atomizers. The next generation of spray models will rely heavily on this approach to better understand and predict the influence of internal and near-field flow on the combustion system.

Download or read book Annual Index abstracts of SAE Technical Papers written by and published by . This book was released on 2007 with total page 1218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mixture Formation in Internal Combustion Engines written by Carsten Baumgarten and published by Springer Science & Business Media. This book was released on 2006-09-28 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic control of mixture formation with modern high-pressure injection systems enables us to achieve considerable improvements of the combustion pr- ess in terms of reduced fuel consumption and engine-out raw emissions. However, because of the growing number of free parameters due to more flexible injection systems, variable valve trains, the application of different combustion concepts within different regions of the engine map, etc., the prediction of spray and m- ture formation becomes increasingly complex. For this reason, the optimization of the in-cylinder processes using 3D computational fluid dynamics (CFD) becomes increasingly important. In these CFD codes, the detailed modeling of spray and mixture formation is a prerequisite for the correct calculation of the subsequent processes like ignition, combustion and formation of emissions. Although such simulation tools can be viewed as standard tools today, the predictive quality of the sub-models is c- stantly enhanced by a more accurate and detailed modeling of the relevant pr- esses, and by the inclusion of new important mechanisms and effects that come along with the development of new injection systems and have not been cons- ered so far. In this book the most widely used mathematical models for the simulation of spray and mixture formation in 3D CFD calculations are described and discussed. In order to give the reader an introduction into the complex processes, the book starts with a description of the fundamental mechanisms and categories of fuel - jection, spray break-up, and mixture formation in internal combustion engines.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Simulation of Nozzle Plume Flows Using a Combined CFD DSMC Approach written by Jyothish D. George and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the Fall Technical Conference of the ASME Internal Combustion Engine Division written by American Society of Mechanical Engineers. Internal Combustion Engine Division. Technical Conference and published by . This book was released on 2006 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 2006 Fall Technical Conference of the ASME Internal Combustion Engine Division written by American Society of Mechanical Engineers. Internal Combustion Engine Division. Technical Conference and published by . This book was released on 2007 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow and Combustion in Reciprocating Engines written by C. Arcoumanis and published by Springer Science & Business Media. This book was released on 2009-06-29 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimization of combustion processes in automotive engines is a key factor in reducing fuel consumption. This book, written by eminent university and industry researchers, investigates and describes flow and combustion processes in diesel and gasoline engines.

Download or read book Fuel Injection in Automotive Engineering written by Kazimierz Lejda and published by BoD – Books on Demand. This book was released on 2012-04-20 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main topic of "Fuel injection in automotive engineering" book is fundamental process that determines the development of internal combustion engines and performances of automotive vehicles. The book collects original works focused on up-to-date issues relevant to improving injection phenomena per se and injection systems as the engine key components.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1989 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Engineering in the Pharmaceutical Industry written by Mary T. am Ende and published by John Wiley & Sons. This book was released on 2019-04-01 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to the important chemical engineering concepts for the development of new drugs, revised second edition The revised and updated second edition of Chemical Engineering in the Pharmaceutical Industry offers a guide to the experimental and computational methods related to drug product design and development. The second edition has been greatly expanded and covers a range of topics related to formulation design and process development of drug products. The authors review basic analytics for quantitation of drug product quality attributes, such as potency, purity, content uniformity, and dissolution, that are addressed with consideration of the applied statistics, process analytical technology, and process control. The 2nd Edition is divided into two separate books: 1) Active Pharmaceutical Ingredients (API’s) and 2) Drug Product Design, Development and Modeling. The contributors explore technology transfer and scale-up of batch processes that are exemplified experimentally and computationally. Written for engineers working in the field, the book examines in-silico process modeling tools that streamline experimental screening approaches. In addition, the authors discuss the emerging field of continuous drug product manufacturing. This revised second edition: Contains 21 new or revised chapters, including chapters on quality by design, computational approaches for drug product modeling, process design with PAT and process control, engineering challenges and solutions Covers chemistry and engineering activities related to dosage form design, and process development, and scale-up Offers analytical methods and applied statistics that highlight drug product quality attributes as design features Presents updated and new example calculations and associated solutions Includes contributions from leading experts in the field Written for pharmaceutical engineers, chemical engineers, undergraduate and graduation students, and professionals in the field of pharmaceutical sciences and manufacturing, Chemical Engineering in the Pharmaceutical Industry, Second Edition contains information designed to be of use from the engineer's perspective and spans information from solid to semi-solid to lyophilized drug products.

Download or read book Proceedings of the Spring Technical Conference of the ASME Internal Combustion Engine Division written by American Society of Mechanical Engineers. Internal Combustion Engine Division. Spring Technical Conference and published by . This book was released on 2000 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atomization and Sprays written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2017-03-27 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of this long-time bestseller provides a framework for designing and understanding sprays for a wide array of engineering applications. The text contains correlations and design tools that can be easily understood and used in relating the design of atomizers to the resulting spray behavior. Written to be accessible to readers with a modest technical background, the emphasis is on application rather than in-depth theory. Numerous examples are provided to serve as starting points for using the information in the book. Overall, this is a thoroughly updated edition that still retains the practical focus and readability of the original work by Arthur Lefebvre.

Download or read book Lecture series written by and published by . This book was released on 2003 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: