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:

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 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 Ignition Delay Time Measurements for Distillate and Synthetic Jet Fuels written by Yi Cao and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As alternatives to traditional petroleum-based fuels are increasingly sought after, the National Jet Fuel Combustion Program (NJFCP) was established to streamline the evaluation and certification of these fuels. The current mandate is for the replacements of traditional fuels to be equally safe and to provide better environmental performance [1]. These so-called "drop-in" jet fuels refer to hydrocarbon fuels that deliver identical combustion performance and are produced from non-petroleum sources [2]. Following the mandate delivered by the NJFCP for alternative fuels, this study aims to improve the traditionally phenomenological understanding of combustion performance by making connections between fuel properties and the chemical composition of fuels. The ignition delay time is an important measure of the combustion performance of fuels, as it is an integrated measure of the fuels' physical and chemical properties, such as volatility, diffusivity, and chemical reactivity. Consequently, it is a very useful validation target in chemical kinetic modeling and has implications in practical aviation phenomena such as, among others, lean blowout, cold-start ignition and altitude relight. Shock tubes are well-suited for ignition delay time measurements, as they provide a well-defined time zero and a quasi-constant temperature and pressure test region behind the reflected shocks. All experiments in this thesis were performed on the Stanford Flexible Application Shock Tube (FAST). Reactive gas mixtures were prepared with equivalence ratios of 1 ± 0.05, and mixed in the shock tube driven section to avoid fuel loss attributed to non-idealities in the jet fuel vapor. Changes in the fuel mole fraction during mixing and ignition were monitored using laser absorption diagnosis at 3.39 μm. The ignition delay time is defined in this study by the onset of emission from electronically excited OH radicals at 306 nm. Ignition delay times were measured in the temperature range of 1200-1500 K and at 4 atm pressure for five distillate jet fuels from refineries around the US (termed geographical fuels), and for six synthetic jet fuels with varying cetane numbers ranging from 30-55 (termed CN fuels). The ignition delay times for A1-3 and C1-9 jet fuels were also measured at 1300 K and at 4 atm. The dependence of combustion properties on fuel chemical composition were investigated using the ignition delay times for these fuels. In particular, the key role that the degree of branching in the jet fuel molecular structure plays in the combustion kinetics and performance is discussed.

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:

Download or read book Experimental Study of Ignition Delay Characteristics for Conventional and Alternative Diesel and Jet Fuels Through Constant Volume Combustion Chamber written by 康莫方 and published by . This book was released on 2020 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physicochemical and Performance Study of Next Generation Alternative Jet Fuels written by Anna Lucrezia Oldani and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Investigation of the Combustion Process of Energy assisted Compression ignition for Low Cetane Number Sustainable Aviation Fuels written by Eri Ramiro Amezcua Cuellar and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jet fuels lack a specification on the cetane number (CN) and the CN of petroleum-derived jet fuels can vary from 30 to over 50. The push to reduce greenhouse gas (GHG) emissions from aviation has led to the development and approval of a range of sustainable jet fuels with even wider potential variation in CNs, ranging from ~15 to ~60. This wide CN variation can lead to misfire and "flame-out" when compression-ignition engines used in small aircraft are operated at altitude. Ground vehicle CI engines are designed to operate on #2 diesel, which has a minimum CN of 40. This work investigates an approach to overcome the challenges associated with operating CI engines on jet fuels with widely varying fuel reactivity. The approach involves depositing thermal energy locally in-cylinder with an ignition assistant (IA) to aid the ignition and combustion of low reactivity fuels, here termed energy-assisted compression-ignition (EACI). Multiple studies were performed in this work to understand various aspects of the EACI combustion process: the ignition and combustion of the fuel jet interacting with an ignition assistant, split-injection injection strategy impacts on the ability to achieve complete stable combustion with acceptable pressure rise rates, and the potential for custom piston bowl shapes to improve the EACI combustion process. Throughout the work, seven fuels were utilized, covering a wide range of CNs, from 2 to 48. The fuels used were a highly-branched alcohol-to-jet fuel (ATJ), F-24 (Jet-A with military additives), two binary blends of ATJ with F-24, toluene, ethanol, and methanol (the last three fuels were only studied with respect to there initial ignition characteristics). In-cylinder pressure measurements, OH chemiluminescence imaging, and schlieren imaging were employed to assess the EACI ignition and combustion process. The results indicate there is an IA temperature threshold of ~1300-1350 K above which the ignition delay for the fuel jet interacting with the IA is independent of fuel CN. However, shot-to-shot variability of the injector and potentially turbulent fluctuations in the fuel jet result in a somewhat stochastic process and cycle-to-cycle variability in ignition for the experimental setup used in this work. Results from split-injection strategies indicate that three different combustion modes can occur during EACI combustion, dependent on fuel reactivity and operating parameters: jet-to-jet propagation, end-gas autoignition, and mixing-controlled combustion. Based on the results, achieving mixing-controlled combustion is desirable as it results in lower pressure rise rate and higher combustion efficiency. The results also showed that custom piston bowl designs could be successfully used to promote mixing-controlled combustion, improving the combustion process. However, small changes in bowl design or operation parameters can result in negative impacts on the combustion process. Taken together, the results provide a first of their kind base of knowledge that can be built on to design efficient EACI combustion engines capable of running on fuels with CNs ranging from 2 to greater than 48.

Download or read book Investigation of Ignition Delay Times of Conventional JP 8 and Synthetic S 8 Jet Fuels written by Jayakishan Balagurunathan and published by . This book was released on 2011 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Photographic Study of Fuel Spray Ignition in a Rapid Compression Machine written by Arun S. P. Solomon and published by . This book was released on 1986 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Natural Gas Ignition Delay Study Under Diesel Engine Conditions in a Combustion Bomb with Glow Plug Assist written by Vito J. Abate and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been conducted in an optically accessible combustion bomb to determine how a natural gas jet interacts with a glow plug, as well as where and under what conditions it ignites in a high swirl combustion chamber. A Cooperative Fuel Research (CFR) engine was used as a rapid compression device to provide bomb pressure charging. Photographs were taken with a high speed ICCD camera while changing glow plug temperature, peak bulk gas temperature, peak bulk gas pressure, injection angle, and local air swirl motion around the glow plug through the use of various shields. The research has shown that combustion chamber design, especially the use of a shield to minimize local air motion around the glow plug, is critical in obtaining ignition of natural gas in 2 ms or less at reasonable bulk gas and glow plug temperatures.

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 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 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 A Study of Autoignition in a Premixed Charge Internal Combustion Engine Using Comprehensive Chemical Kinetics written by Philip Michael Dimpelfeld and published by . This book was released on 1985 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Alternative Fuels for Compression Ignition Engines written by Zainal Ambri Abdul Karim and published by Springer. This book was released on 2018-03-20 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the development and utilization of alternative fuels in order to reduce or control the environmental impact of internal combustion engine exhaust gases. Discussing alternative fuels such as dual fuel techniques, rubber seed/palm oil biodiesel, syngas dual-fuelling, water-in-diesel emulsions and gasification of date palm seeds, it is a valuable resource for researchers in the field of engine development and on alternative fuels.

Download or read book Ignition Delay at Various High Pressures An Experimental Study written by Ritu Gaur and published by . This book was released on 2019-10-16 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research Paper (postgraduate) from the year 2019 in the subject Engineering - Chemical Engineering, course: M.TECH, language: English, abstract: This work is an experimental study for the measurement of ignition delay characteristics of burning fuel sprays in cylindrical combustion chambers. It is carried out on hot air and high pressure. The objective of the study is to investigation the effect of hot air temperature and a well as high pressure on ignition delay of diesel fuel sprays. The effect of blending of n-Pentane with pure diesel was investigated. An experimental set up was design for this purpose with the emphasis on optical method for measurement of ignition delay at various pressures. The results presented here show that ignition delay of diesel fuel spray decreases with increase in the temperature and pressure of hot air. Results also show the effect of methyl group being more dominant at low ignition temperatures and that of alkyl group being more dominant at higher temperature. Blending of n-pentane with diesel fuel, increase its ignition delay at low ignition temperatures. However, as the concentration of blending fuel was increased beyond 30%, the ignition temperature increase. Ignition temperature for 40% pentane blends is much higher that the pure diesel.