Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Effect Of Vortex Roll Up And Crevice Mass Flow On Ignition In A Rapid Compression Machine
Download Effect Of Vortex Roll Up And Crevice Mass Flow On Ignition In A Rapid Compression Machine full books in PDF, epub, and Kindle. Read online Effect Of Vortex Roll Up And Crevice Mass Flow On Ignition In A Rapid Compression Machine ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Effect of Vortex Roll-up and Crevice Mass Flow on Ignition in a Rapid Compression Machine by : Mickael Chomier
Download or read book Effect of Vortex Roll-up and Crevice Mass Flow on Ignition in a Rapid Compression Machine written by Mickael Chomier and published by . This book was released on 2013 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis is to understand the influence of the non-ideal effects in Rapid Compression Machines (RCM), namely the vortex roll-up and mass flow into the crevice, on autoignition. The effect of the vortex roll-up is studied computationally using CFD simulations of autoignition in a RCM. Whereas, the effect of the crevice mass flow is investigated experimentally by studying isooctane autoignition. Over the last two decades, experimental data of the nature of species evolution profiles and ignition delays from RCMs has been used to develop and validate chemical kinetic mechanisms at low-to-intermediate temperatures and elevated pressures. A significant portion of this overall dataset is from RCMs that had not employed a creviced piston to contain the roll-up vortex. The detrimental influence of the roll-up vortex and the thermokinetic interactions due to the resulting temperature non-homogeneity during the negative temperature coefficient (ntc) regime have been documented in the literature. However, the adequacy of the homogeneous modeling of RCMs without creviced pistons during reactive conditions has not been investigated. In this work, computational fluid dynamics simulations of an RCM without a creviced piston are conducted for autoignition of n-heptane over the entire ntc regime over a range of compressed pressures from 5 to 18 bar. The results from the CFD simulations highlight the non-homogeneity of autoignition and reveal significant quantitative discrepancy in comparison to homogeneous modeling, particularly for the hot ignition delay in the ntc regime. Specifically, the roll-up vortex induced temperature non-homogeneity leads to diminution of the ntc behavior. The experimental data from RCMs without creviced piston needs to be taken with caution for quantitative validation and refinement of kinetic mechanism, particularly at conditions when ntc behavior is highly pronounced. Rapid Compression Machines (RCMs) often employ creviced pistons to suppress the formation of the roll-up vortex. However, the use of a creviced piston promotes mass flow into the crevice when heat release takes place in the main combustion chamber. This multi-dimensional effect is not accounted for in the prevalent volumetric expansion approach for modeling RCMs. The method of crevice containment, on the other hand, avoids post-compression mass flow into the crevice. In order to assess the effect of the crevice mass flow on ignition in a RCM, experiments were conducted for autoignition of isooctane in a RCM with creviced piston in the temperature range of 680-940 K and at compressed pressures of ~15.5 and 20.5 bar in two ways. In one situation, post-compression mass flow to the crevice is avoided by crevice containment and in other it is allowed. Experiments show that the crevice mass flow can lead to significantly longer ignition delays. Experimental data from both scenarios is modeled using adiabatic volumetric expansion approach and an available kinetic mechanism. The simulated results show less pronounced effect of crevice mass flow on ignition delay and highlight the deficiency of the volumetric expansion method owing to its inability to describe coupled physical-chemical processes in the presence of heat release. Results indicate that it is important to include crevice mass flow in the physical model for improved modeling of experimental data from RCMs for consistent interpretation of chemical kinetics. The use of crevice containment, however, avoids the issue of mass flow altogether and offers an alternative and sound approach.
Book Synopsis A Rapid Compression Machine with the Novel Concept of Crevice Containment by : Anil Bhari
Download or read book A Rapid Compression Machine with the Novel Concept of Crevice Containment written by Anil Bhari and published by . This book was released on 2010 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid Compression Machines (RCMs) typically incorporate creviced pistons to suppress the formation of the roll-up vortex. The use of a creviced piston, however, can enhance other multi-dimensional effects inside the RCM due to the crevice zone being at a lower temperature than the main reaction chamber. In this work, such undesirable effects of the creviced piston are first highlighted through computational fluid dynamics simulations of n-heptane ignition in an RCM. Specifically, the results show that in an RCM with a creviced piston, additional mass flow takes place from the main combustion chamber to the crevice zone during the first-stage ignition. This phenomenon is not captured by the conventional zero-dimensional modeling approaches. Consequently, a novel approach of 'crevice containment' is introduced and evaluated. According to this approach, in order to avoid the undesirable effects of the creviced piston, the crevice zone is separated from the main reaction chamber at the end of compression. The computational results with this novel approach show significant improvement in the fidelity of the zero-dimensional modeling in terms of predicting the overall ignition delay and pressure rise in the first-stage ignition. In addition, this approach also offers other advantages, namely a reduction in the rate of post-compression pressure drop and improved data during species sampling experiments. An RCM is subsequently designed and successfully fabricated with the feature of 'crevice containment' for the purpose of chemical kinetics studies at elevated pressures and temperatures. Characterization experiments for the newly built RCM show that the operation of the RCM is free from any vibrations, allows fast compression (22 ms), compressed pressures up to 100 bar and the experimental data obtained is highly reproducible. Using this facility, autoignition investigations are conducted for Hydrogen at a pressure of 50 bar. The experiments are modeled using the kinetic mechanism of O'Conaire et al. (2004). Results showed that the mechanism of O'Conaire et al. agree very well with the experimental data.
Book Synopsis An Investigation of Phase-change Effects During Rapid Compression Machine Experiments by : Colin Banyon
Download or read book An Investigation of Phase-change Effects During Rapid Compression Machine Experiments written by Colin Banyon and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid compression machines (RCMs) are well characterized laboratory scale devices capable of achieving internal combustion (IC) engine relevant thermodynamic environments. These machines are often used to collect ignition delay times as targets for gas-phase chemical kinetic fuel autoigntion models. Modern RCMs utilize creviced piston(s) to improve charge homogeneity and allow for an adequate validation of detailed chemistry mechanisms against experiments using computationally efficient, homogeneous reactor models (HRMs). Conventionally, experiments are preformed by introducing a premixed gas of fuel + oxidizer + diluent into the machine, which is compressed volumetrically via a piston. Experiments investigating low-vapor pressure fuels (e.g. diesels, biodiesels, jet fuels, etc.) and surrogates can be conducted by preheating both the charge as well as the machine. This method of fuel loading can lead to pretest fuel pyrolysis as well as machine seal degradation. Under some conditions loading a fuel aerosol of finely atomized liquid droplets in an oxidizer + diluent bath gas (i.e. wet compression) has been suggested to extend the capabilities of RCM experiments to involatile fuels. This work investigates phase-change effects during RCM experiments, especially for aerosol-fueling conditions, while the methodology can be applied to gas-phase fuel experiments where fuel condensation can occur at the compressed conditions within the boundary layer region. To facilitate this study a reduced-order, physics-based model is used. This work highlights important machine-scale influences not investigated in previous work, and provides additional detail concerning an aerosol RCM{u2019}s capabilities and limitations. A transient formulation is developed for the multi-phase transport within the RCM reaction chamber as well as the flow to the piston crevice region during both the compression and delay periods. The goal of this work is threefold. First, an a priori knowledge of the stratification present under various conditions can help determine an optimum machine geometry so that discrepancies between experimental data sets and 0D kinetics simulations are minimized for involatile fuels. Second, the model is computationally tractable to prescribe heat loss rates to an HRM during simulations of experiments so that physical effects can be incorporated into simulations using detailed chemistry. Finally, heat loss rates that are prescribed to the HRM are only a function of machine geometry, and are independent of ad hoc and empirically derived fits that vary between facilities. Thus a more adequate comparison of data between RCM facilities and with existing literature can be made.
Book Synopsis The Effect of Diluent Gases In The Shock Tube and Rapid Compression Machine by :
Download or read book The Effect of Diluent Gases In The Shock Tube and Rapid Compression Machine written by and published by . This book was released on 2007 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studying the details of hydrocarbon chemistry in an internal combustion engine is not straightforward. A number of factors, including varying conditions of temperature and pressure, complex fluid motions, as well as variation in the composition of gasoline, render a meaningful characterization of the combusting system difficult. Some simplified experimental laboratory devices offer an alternative to complex engine environments: they remove some of the complexities that exist in real engines but retain the ability to work under engine-relevant conditions. The choice of simplified experimental devices is limited by the range of temperature and pressure at which they can operate; only the shock tube and rapid compression machine (RCM) can reach engine-relevant temperatures and pressures quickly enough and yet withstand the high pressures that occur after the ignition event. Both devices, however, suffer a common drawback: the use of inert diluent gases has been shown to affect the measured ignition delay time under some experimental conditions. Interestingly, this effect appears to be opposite in the shock tube and RCM: in the comparative study of the carrier gases argon and nitrogen, argon decreases the ignition delay time in the shock tube, but increases it in the RCM. This observation is investigated in more detail in this study.
Book Synopsis Fuel Ignition in a Rapid Compression Machine by : W. W. Haskell
Download or read book Fuel Ignition in a Rapid Compression Machine written by W. W. Haskell and published by . This book was released on 1969 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental and Numerical Analysis of the Effects of Test Variables on Auto-ignition in a Rapid Compression Machine by : Chaitanya Wadkar
Download or read book Experimental and Numerical Analysis of the Effects of Test Variables on Auto-ignition in a Rapid Compression Machine written by Chaitanya Wadkar and published by . This book was released on 2021 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effects of Air Motion on Combustion in the M.I.T. Rapid-Compression Machine by : P. Ranganath Nayak
Download or read book The Effects of Air Motion on Combustion in the M.I.T. Rapid-Compression Machine written by P. Ranganath Nayak and published by . This book was released on 1965 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rapid Compression Machine Measurements of Ignition Delays for Primary Reference Fuels by : Pyongwan Park
Download or read book Rapid Compression Machine Measurements of Ignition Delays for Primary Reference Fuels written by Pyongwan Park and published by . This book was released on 1990 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Data Base Generation and Modeling of Homogeneous Charge Compression Ignition Using a Rapid Compression Machine by : Ferran Alberto Ayala
Download or read book Data Base Generation and Modeling of Homogeneous Charge Compression Ignition Using a Rapid Compression Machine written by Ferran Alberto Ayala and published by . This book was released on 2001 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Autoignition Measurements and Modeling in a Rapid Compression Machine by : Daeyup Lee
Download or read book Autoignition Measurements and Modeling in a Rapid Compression Machine written by Daeyup Lee and published by . This book was released on 1997 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Autoignition Measurements and Modeling in a Rapid Compression Machine by :
Download or read book Autoignition Measurements and Modeling in a Rapid Compression Machine written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: By Daeyup Lee.
Book Synopsis Autoignition Measurements for Oxygenated Fuels in a Rapid Compression Machine by : Daeyup Lee
Download or read book Autoignition Measurements for Oxygenated Fuels in a Rapid Compression Machine written by Daeyup Lee and published by . This book was released on 1993 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ignition Delay Study of Next Generation Alternative Jet Fuels in a Rapid Compression Machine by :
Download or read book Ignition Delay Study of Next Generation Alternative Jet Fuels in a Rapid Compression Machine written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Crevice Volume Effect on Spark Ignition Engine Efficiency by : Patrick Michael Smith
Download or read book Crevice Volume Effect on Spark Ignition Engine Efficiency written by Patrick Michael Smith and published by . This book was released on 2013 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: A set of experiments and a simulation study are completed to quantify the effect of the piston crevice on engine efficiency. The simulation study breaks down the loss mechanisms on brake efficiency at different displacement volumes (300 - 500 cc) and compression ratios (8-20). Experiments focus on indicated efficiencies for a narrow range of compression ratios (9.24- 12.57) with different piston crevice volumes. Piston crevice volume is increased in two steps by machining a groove into the piston top land, and is decreased by raising the top ring. Indicated efficiency is measured at various loads (0.4 - 1.0 bar MAP), speeds (1500, 2000, 2500 rpm), and coolant temperatures (50°C and 80°C). All data points compared in this study are recorded at MBT timing with a relative air-fuel ratio ([gamma]) of 1. For the baseline case (CR = 9.24, speed = 2000 rpm, coolant = 80°C), increased crevice volume results in an indicated efficiency degradation of 0.3-0.5%-points per 1000 mm3. This absolute decrease corresponds to a 1.2-1.5% relative decrease for a 100% increase in crevice volume; referenced to the control piston crevice modification. Decreasing crevice volume leads to a gain in indicated efficiency of 2.3-3.5%-points per 1000 mm3 , which corresponds to a 6.9- 11.8% relative increase for a 100% decrease in crevice volume; referenced to the control piston crevice modification. Results of the experimental investigation, when compared across compression ratio, engine speed, and coolant temperature, show that the crevice effect on efficiency is largely independent of these three parameters. Large gains from decreased piston crevice volume prompt renewed discussions on piston top land, top ring, and crown design.
Author :Frédérique Battin-Leclerc Publisher :Springer Science & Business Media ISBN 13 :1447153073 Total Pages :657 pages Book Rating :4.4/5 (471 download)
Book Synopsis Cleaner Combustion by : Frédérique Battin-Leclerc
Download or read book Cleaner Combustion written by Frédérique Battin-Leclerc and published by Springer Science & Business Media. This book was released on 2013-09-06 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: This overview compiles the on-going research in Europe to enlarge and deepen the understanding of the reaction mechanisms and pathways associated with the combustion of an increased range of fuels. Focus is given to the formation of a large number of hazardous minor pollutants and the inability of current combustion models to predict the formation of minor products such as alkenes, dienes, aromatics, aldehydes and soot nano-particles which have a deleterious impact on both the environment and on human health. Cleaner Combustion describes, at a fundamental level, the reactive chemistry of minor pollutants within extensively validated detailed mechanisms for traditional fuels, but also innovative surrogates, describing the complex chemistry of new environmentally important bio-fuels. Divided into five sections, a broad yet detailed coverage of related research is provided. Beginning with the development of detailed kinetic mechanisms, chapters go on to explore techniques to obtain reliable experimental data, soot and polycyclic aromatic hydrocarbons, mechanism reduction and uncertainty analysis, and elementary reactions. This comprehensive coverage of current research provides a solid foundation for researchers, managers, policy makers and industry operators working in or developing this innovative and globally relevant field.
Book Synopsis Turbulent Combustion by : Norbert Peters
Download or read book Turbulent Combustion written by Norbert Peters and published by Cambridge University Press. This book was released on 2000-08-15 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combustion of fossil fuels remains a key technology for the foreseeable future. It is therefore important that we understand the mechanisms of combustion and, in particular, the role of turbulence within this process. Combustion always takes place within a turbulent flow field for two reasons: turbulence increases the mixing process and enhances combustion, but at the same time combustion releases heat which generates flow instability through buoyancy, thus enhancing the transition to turbulence. The four chapters of this book present a thorough introduction to the field of turbulent combustion. After an overview of modeling approaches, the three remaining chapters consider the three distinct cases of premixed, non-premixed, and partially premixed combustion, respectively. This book will be of value to researchers and students of engineering and applied mathematics by demonstrating the current theories of turbulent combustion within a unified presentation of the field.
Book Synopsis Aulton's Pharmaceutics by : Michael E. Aulton
Download or read book Aulton's Pharmaceutics written by Michael E. Aulton and published by Elsevier Health Sciences. This book was released on 2013 with total page 909 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Pharmaceutics is the art of pharmaceutical preparations. It encompasses design of drugs, their manufacture and the elimination of micro-organisms from the products. This book encompasses all of these areas."--Provided by publisher.
