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Characterization Of Impinging Diesel Sprays With A Reduced Order Model And Gas Jet Experiments
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Book Synopsis Characterization of Impinging Diesel Sprays with a Reduced-order Model and Gas Jet Experiments by : Daniel Ruth
Download or read book Characterization of Impinging Diesel Sprays with a Reduced-order Model and Gas Jet Experiments written by Daniel Ruth and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mixing of a diesel spray with in-cylinder gases is driven by both turbulent mixing during the free-jet penetration phase and by mixing during its impingement on surfaces such as the piston bowl. Current reduced order models, and many experiments, focus solely on the free-jet penetration phase, although jet-wall interaction occurs during a significant portion of the duration of a fuel injection in both small-bore and large-bore engines. A control volume-based model for the spreading of an impinging spray along a flat wall is presented as a first step towards capturing key jet processes during the impingement phase of fuel injection. Schlieren measurements of impinging gaseous jets are used to evaluate the model, and a strategy of accounting for the varying density in gas jet injections is introduced. The model, coupled with the free jet model of Musculus and Kattke, is shown to predict published impinging diesel data as well. The model is then used to compare global entrainment effects at various diesel conditions, providing a means for evaluating the effects of combustion parameters on entrainment with more realistic engine geometries. Finally, mixing phenomena relating to advanced combustion techniques, including rate-shaping and the use of multiple injections, are investigated with the model.
Book Synopsis Gas Jet Studies for the Characterization of Advanced Injection Schedules and Bowl Design in Diesel Engines by : Meghan Borz
Download or read book Gas Jet Studies for the Characterization of Advanced Injection Schedules and Bowl Design in Diesel Engines written by Meghan Borz and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In-cylinder strategies such as advanced fuel injection schedules and optimal piston bowl designs are often utilized in diesel combustion for to improve efficiency and/or reduce emissions. The large design space for injection schedules makes choosing the optimal schedule for an engine particularly challenging. Additionally, experimental in-engine studies of advanced injection schedules are time-consuming and costly. Gas jet experiments can provide a good approximation for the behavior of diesel jets and more tests can be conducted in a shorter period of time without incurring the costs of an engine research facility. The goal of this work is to gain a further understanding of some of the fundamental fluid mechanics of multiple injections, jet-jet interactions, and jets impinging on surfaces.Gas jet experiments are conducted using z-schlieren and acetone tracer planar laser-induced fluorescence (PLIF). Three studies are conducted focusing on free jets, multiple jet interactions, jet-jet interaction, and bowl geometry effects. The first study is a comparison of penetration results for helium gas jets with penetration results for vaporizing and non-vaporizing sprays, which shows that by non-dimensionalizing the results of gas jet experiments, the penetration curve follows a similar trend to the non-dimensionalized penetration curve for vaporizing and non-vaporizing liquid sprays.The second study explores the fluid mechanic interactions between multiple injections and the effects of injection duration and dwell. The schlieren results of the multiple-injection studies showed that before the end of injection (EOI) the non-dimensional jet-tip penetration was not significantly different for the first and second injection, however, the average dispersion half angle during the quasi-steady portion of injection was higher for the first injection than for the second injection. There are two multiple-injection cases where the average dispersion half angle of the second injection is higher than that of the first injection by a statistically significant amount. These differences in jet dispersion angle are indicative of differences in mixing and entrainment during the first and second injections. Future studies with acetone-PLIF will allow the concentration to be quantified and differences in the jet composition for the first and second injections in multiple-injection schemes to be compared.The last study focuses on the effects of piston bowl geometry and the angle between interacting jets. The effects of the geometry on fluid recirculation and mixing are studied using schlieren and PLIF with jets of acetone vapor and air and two different piston bowl designs. The results showed that a deeper bowl and wider angle between the jets allows for improved mixing and air utilization.
Book Synopsis HIGH INJECTION PRESSURE IMPINGING DIESEL SPRAY CHARACTERISTICS AND SUBSEQUENT SOOT FORMATION IN REACTING CONDITIONS by :
Download or read book HIGH INJECTION PRESSURE IMPINGING DIESEL SPRAY CHARACTERISTICS AND SUBSEQUENT SOOT FORMATION IN REACTING CONDITIONS written by and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : The spray impingement in diesel engines attracts the attention of engine researchers in recent decades as the physical size of the engine is reduced. Due to the spray impingement, the atomization, vaporizing and air-fuel mixing quality is altered compared to a free spray. For emission control, soot is one of the major particulate emissions from diesel combustion and its formation in an impinged spray is worthy to be investigated. Firstly, to understand the impinged spray characteristics, the experiments for both non-vaporizing and reacting conditions were conducted in a constant volume combustion vessel. The impinged spray was captured by a high-speed camera and the instantaneous spray propagation distance and rate were obtained. For a better understanding, the microscopic behavior of the spray propagation, the curvature of the impinged spray was calculated and a relationship between local fuel distribution and soot formation was found. After that, the apparent heat release rate from an impinge spray combustion and the heat flux through the impingement were analyzed. The apparent heat release rate was obtained by the internal chamber pressure and the heat flux was measured by heat flux probes embedded in the impinging plate. Then, the soot formation of an impinged spray was both studied from experiments and simulations. In the experiments, the natural luminosity mainly due to the incandescence of soot particles was captured by the high-speed camera. A computational fluid dynamics (CFD) approach was adopted to quantitatively study the soot formation in terms of absolute soot mass and soot mass fractions in the vicinity of the wall. In the last, the film formation under different ambient temperatures, impinging distances, and oxygen concentration was investigated in terms of film area and thickness. The impact of film formation on the soot outcomes was then investigated by comparing the rate of film vaporization and soot formation. To summarize, the main goal of this dissertation is going to benefit the understanding of the impinged spray in reacting diesel-relevant engine conditions. From experiments, a global view of soot formation in an impinged spray was analyzed and the mechanism of soot formation was further revealed by the CFD simulations.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-11 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Disintegrating Process and Spray Characterization of Fuel Jet Injected by a Diesel Nozzle by : M. Arai
Download or read book Disintegrating Process and Spray Characterization of Fuel Jet Injected by a Diesel Nozzle written by M. Arai and published by . This book was released on 1984 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Some Characteristics of Impinging Jet Fuel Sprays by : Frank Gabron
Download or read book Some Characteristics of Impinging Jet Fuel Sprays written by Frank Gabron and published by . This book was released on 1955 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Book Synopsis Multi-dimensional Modeling of Fuel Films and Spray-wall Interactions Resulting from Impinging Sprays by : Donald W. Stanton
Download or read book Multi-dimensional Modeling of Fuel Films and Spray-wall Interactions Resulting from Impinging Sprays written by Donald W. Stanton and published by . This book was released on 1998 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Proceedings of the 3rd International Conference on Liquid Atomisation and Spray Systems at Imperial College, London, 8-9-10 July 1985 by :
Download or read book Proceedings of the 3rd International Conference on Liquid Atomisation and Spray Systems at Imperial College, London, 8-9-10 July 1985 written by and published by . This book was released on 1985 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Characterization of the Spray Formed by Two Impinging Jets in Liquid Rocket Injector by : F. Brault
Download or read book Experimental Characterization of the Spray Formed by Two Impinging Jets in Liquid Rocket Injector written by F. Brault and published by . This book was released on 1985 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Flow and Heat Transfer Characteristics of Impinging Transient Diesel Sprays by : Constantine Arcoumanis
Download or read book Flow and Heat Transfer Characteristics of Impinging Transient Diesel Sprays written by Constantine Arcoumanis and published by . This book was released on 1994 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Technical Literature Abstracts by : Society of Automotive Engineers
Download or read book Technical Literature Abstracts written by Society of Automotive Engineers and published by . This book was released on 2000 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Diesel Fuel Spray Characterization Using Infrared Extinction and Scattering Methods by : Eric W. Jepsen
Download or read book Diesel Fuel Spray Characterization Using Infrared Extinction and Scattering Methods written by Eric W. Jepsen and published by . This book was released on 1998 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Large-eddy Simulation Modeling of Diesel Sprays by : Chi-Wei Tsang
Download or read book Large-eddy Simulation Modeling of Diesel Sprays written by Chi-Wei Tsang and published by . This book was released on 2017 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this study is to develop/improve physical models for large-eddy simulations of Diesel sprays. The stochastic Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) atomization and breakup model, the synthetic eddy injection model, the droplet rotation model, and the sub-grid scale (SGS) dispersion model were developed and tested. Using the classical KH-RT model, it was found that simulation results are sensitive to several model parameters such as length and time scales of instability waves. The idea of the stochastic KH-RT model is to determine these parameters stochastically and dynamically. This is an attempt to reduce the sensitivity of the model parameters partly resulting from the incapability of predicting breakup mechanisms other than wave instabilities in the classical KH-RT model. The synthetic eddy injection model predicts fluctuations of the Lagrangian parcel initial velocity. The model attempts to simulate turbulence at the nozzle exit without the need of internal nozzle flow simulations, by superimposing a number of virtual coherent structures. The performance of these two newly developed models was compared to the original ones, namely the classical KH-RT and the cone angle injection models. Two experimental databases, the Engine Combustion Network (ECN) constant-volume sprays and the Engine Research Center optical engine sprays were used to validate the models. A number of simulated quantities such as liquid projected mass density, liquid and vapor penetrations, fuel vapor profiles, ignition delays, and lift-off lengths, were compared against the data. The stochastic KH-RT model improved the prediction of the projected mass density downstream and liquid penetrations in a range of operating conditions (errors within 5 %) without tuning the model constants case by case. The synthetic eddy injection model improved the prediction of vapor penetrations at early stage of injection since the development of instability modes and turbulent transport in the near-nozzle region were better resolved. The model also shows less grid sensitivity. Overall, using these two new models overcomes some limitations in the original models and makes LES as a more predictive tool for Diesel sprays. The droplet rotation model considers droplet force and torque due to relative rotational motions between droplets and gas. Simulation results of the ECN non-vaporizing and vaporizing sprays with and without using the rotation model were compared. It was found that the droplet rotation has negligible effect. This is because the droplet response time scale to the rotational motion is much smaller than that to the translational motion. That is, slip angular velocity approaches to zero much faster, resulting in much smaller rotational force than the drag force. The SGS dispersion model considers the effect of sub-grid motions on Diesel spray dispersion. The model assumes that the SGS dispersion velocity is decomposed into the deterministic and the stochastic parts. The deterministic part is modeled by the approximate deconvolution method and the stochastic part is assumed to be isotropic and Gaussian distributed. It was found that the two model parameters, variance of the Gaussian distribution and turbulence correlation time, have a critical effect on the spatial distribution of droplets with small inertia downstream of the spray. Larger variance or longer turbulence correlation time predicts wider liquid spray angle. However, they have small effect on predicting resolved gas-phase statistics. The primary reason for this is that the motion of high-momentum liquid blobs in the near-nozzle region leading to air entrainment and subsequent gas jet development is little influenced by the SGS dispersion. Moving further downstream a quasi-equilibrium is established between the two phases, resulting in relatively small slip velocities. Therefore, it was found that the spray momentum source term in the gas momentum equation is much smaller than the other terms in the downstream region.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 700 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.
Book Synopsis Annual Index/abstracts of SAE Technical Papers by :
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:
