Download or read book Advanced Rapid Compression Machine Test Methods and Surrogate Fuel Modeling for Bio derived Jet and Diesel Fuel Autoignition written by Casey M. Allen and published by . This book was released on 2012 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gasoline Surrogate Modeling of Gasoline Ignition in a Rapid Compression Machine and Comparison to Experiments written by and published by . This book was released on 2011 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history during ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first-stage (when observed) and second-stage ignition delay times and of heat release rate. The experimental and computational results are used to gain insight into low and intermediate temperature processes during gasoline ignition.

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.

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:

Download or read book Ignition Study in Rapid Compression Machine written by Tairin Hahn and published by . This book was released on 2008 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: As it becomes more and more difficult to find "easy" oil, various alternative fuels are introduced to the markets. These fuels have chemical properties that are different from the traditional gasoline and diesel fuels so that engine efficiency and other engine behaviors may be affected To improve engine efficiency and to identify which alternative fuel is the cleanest fuel solution, it is necessary to compile information about the ignition delay, which governs auto-ignition in spark-ignition (SI), compression-ignition (CI) and homogeneous charge compression-ignition (HCCI) engines. In this study, we measured ignition delay on the Rapid Compression Machine (RCM). RCM is a single-stroke device, which compresses uniform mixtures to engine-like condition. We can interpret from the pressure the detailed heat release process. A comprehensive ignition delay database of toluene/n-heptane mixtures and gasoline/ethanol mixtures was established The data allow us to calculate the auto-ignition behavior in engines. Depending on application the correct choice of alternative fuels may be made.

Download or read book Kinetic Modeling of Hydrocarbon Autoignition at Low and Intermediate Temperatures in a Rapid Compression Machine written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A computer model is used to examine oxidation of hydrocarbon fuels in a rapid compression machine. For one of the fuels studied, n-heptane, significant fuel consumption is computed to take place during the compression stroke under some operating conditions, while for the less reactive n-pentane, no appreciable fuel consumption occurs until after the end of compression. The third fuel studied, a 60 PRF mixture of iso-octane and n-heptane, exhibits behavior that is intermediate between that of n-heptane and n-pentane. The model results indicate that computational studies of rapid compression machine ignition must consider fuel reaction during compression in order to achieve satisfactory agreement between computed and experimental results.

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.

Download or read book Experiments on the Effects of Dilution and Fuel Composition on Ignition of Gasoline and Alternative Fuels in a Rapid Compression Machine written by Prasanna Chinnathambi and published by . This book was released on 2019 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the first part of this work, ignition of methane-air mixtures under excess air dilution is studied. When excess air is used in SI engine operation, thermal efficiency is increased due to increase in compression ratio together with reduced pumping and heat loses. However, stable operation with excess air is challenging due to poor flammability of the resulting diluted mixture. Hence in order to achieve stable and complete combustion a turbulent jet ignition (TJI) system is used to improve combustion of lean methane-air mixtures. Various nozzle designs and operating strategies for a TJI system were tested in a rapid compression machine. 10-90% burn duration measurements were useful in assessing the performance of the nozzle designs while the 0-10% burn durations indicated if optimal air-fuel ratio is achieved within the pre-chamber at the time of ignition. The results indicated that distributed-jets TJI system offered faster and stable combustion while the concentrated-jets TJI system offered better dilution tolerance.Knock in a SI engine occurs due to autoignition of the end gas mixture and typically occurs in the negative temperature coefficient (NTC) region of the fuel-air mixture. Dilution of intake charge with cold exhaust recirculation gases (EGR) reduces combustion temperatures and decreases mixture reactivity thereby reducing knocking tendency. This enables optimal spark timings to be used, thereby increasing efficiency of SI engines which would otherwise be knock limited. Effect of cold EGR dilution is studied in the RCM by measuring the autoignition delay times of gasoline and gasoline surrogate mixtures diluted with varying levels of CO2. The autoignition experiments in the RCM were performed using a novel direct test chamber (DTC) charge preparation approach. The DTC approach enabled mixture preparation directly within the combustion chamber and eliminated the need for mixing tanks. Effect of CO2 dilution in retarding the autoignition delay times was more pronounced in the NTC region, while it was weaker in the low temperature and high temperature regions. The retarding effect was found to be dependent on both the octane number and the fuel composition of the gasoline being studied.Finally, the effect of substituting ethanol(biofuel) in gasoline surrogates for up to 40% by volume is studied. Ethanol is an octane booster, but it blends antagonistically with aromatics such as toluene and synergistically with alkanes with respect to the resulting octane number of the blends. In order to study this blending effect, two gasoline surrogates containing only alkanes (PRF), and alkanes with large amounts of toluene (TRF) are blended with varying levels of ethanol. The ignition delay times of the resulting mixtures are measured in a rapid compression machine and kinetic analysis was carried out using numerical simulations. The kinetic analysis revealed that ethanol controlled the final stages of ignition for the PRF blends when more than 10% by volume of ethanol is present. However, in the TRF blends, toluene controlled the ignition until mole fractions of ethanol became higher than the toluene indicating the reason for the antagonistic blending nature. It was found that the RON values of the resulting blends matched the trend of the ignition delay times recorded at 740K and 21 bar compressed conditions. This enables qualitative assessment of the RON numbers for new biofuel blends by measuring their ignition delay times in the RCM.

Download or read book Gasoline Compression Ignition Technology written by Gautam Kalghatgi and published by Springer Nature. This book was released on 2022-01-17 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on gasoline compression ignition (GCI) which offers the prospect of engines with high efficiency and low exhaust emissions at a lower cost. A GCI engine is a compression ignition (CI) engine which is run on gasoline-like fuels (even on low-octane gasoline), making it significantly easier to control particulates and NOx but with high efficiency. The state of the art development to make GCI combustion feasible on practical vehicles is highlighted, e.g., on overcoming problems on cold start, high-pressure rise rates at high loads, transients, and HC and CO emissions. This book will be a useful guide to those in academia and industry.

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:

Download or read book Surrogate Modeling of Alternative Jet Fuels for Study of Autoignition Characteristics written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling the Fuel Spray and Combustion Process of the Ignition Quality Tester with KIVA 3V written by and published by . This book was released on 2010 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing advanced compression ignition and low-temperature combustion engines depends increasingly on chemical kinetic ignition models, but rigorous experimental validation of the models has been limited. Shock tubes and rapid compression machines are often limited to premixed gas-phase studies, precluding the use of realistic, low volatility diesel or biodiesel surrogates. The Ignition Quality Tester (IQT) constant-volume spray combustion system measures ignition delay of low-volatility fuels and could validate ignition models experimentally, but a better understanding of the IQT's processes is needed. KIVA-3V was used to develop a 3D CFD model that accurately reproduces ignition behavior and resolves temperature and equivalence ratio regions inside the IQT. The model's fuel spray characteristics (e.g., velocity) are experimentally validated, and it provides insight, vital to expanding the fuel research capabilities of the IQT, into the complex interaction between fuel spray and combustion processes.

Download or read book Fuel air Mixing and Diesel Combustion in a Rapid Compression Machine written by Eric Norbert Balles and published by . This book was released on 1987 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Auto ignition Characterisation of Synthetic Fuels Via Rapid Compression Machine written by Myeji Chrysostom Materego and published by . This book was released on 2015 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling and Experimental Investigation of Methylcyclohexane Ignition in a Rapid Compression Machine written by W. J. Pitz and published by . This book was released on 2005 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Compression Ignition Natural Gas Diesel Dual Fuel Engines written by Hongsheng Guo and published by Frontiers Media SA. This book was released on 2021-03-23 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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: