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1
Desantes, Jose M., Jose M. Garcia-Oliver, Ricardo Novella i Leonardo Pachano. "A numerical study of the effect of nozzle diameter on diesel combustion ignition and flame stabilization". International Journal of Engine Research 21, nr 1 (19.07.2019): 101–21. http://dx.doi.org/10.1177/1468087419864203.
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The role of nozzle diameter on diesel combustion is studied by performing computational fluid dynamics calculations of Spray A and Spray D from the Engine Combustion Network. These are well-characterized single-hole sprays in a quiescent environment chamber with thermodynamic conditions representative of modern diesel engines. First, the inert spray evolution is described with the inclusion of the concept of mixing trajectories and local residence time into the analysis. Such concepts enable the quantification of the mixing rate, showing that it decreases with the increase in nozzle diameter. In a second step, the reacting spray evolution is studied focusing on the local heat release rate distribution during the auto-ignition sequence and the quasi-steady state. The capability of a well-mixed-based and a flamelet-based combustion model to predict diesel combustion is also assessed. On one hand, results show that turbulence–chemistry interaction has a profound effect on the description of the reacting spray evolution. On the other hand, the mixing rate, characterized in terms of the local residence time, drives the main changes introduced by the increase of the nozzle diameter when comparing Spray A and Spray D.
2
Jafarmadar, Samad, Shram Khalilarya, Sina Shafee i Ramin Barzegar. "Modeling the effect of spray/wall impingement on combustion process and emission of DI diesel engine". Thermal Science 13, nr 3 (2009): 23–33. http://dx.doi.org/10.2298/tsci0903023j.
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This work is presented to study the effect of spray impinging on the combustion process and emissions in a direct injection diesel engine at various engine speeds. Computations are carried out using a three-dimensional modeling for sprays, spray-wall interactions, flow field, emission, and combustion process. Results indicate an increase in engine speed leads to increased spray impinging (wall film formation), turbulence intensity and average wall temperature in cylinder. The enhanced air/fuel mixing and intensified evaporation of wall film decreases soot emission by reducing the extent of the fuel rich regions specially in impinging zones. Also at higher engine speeds, combustion is delayed and fuel is consumed in a shorter time period by the enhanced air and fuel mixing. The shorter combustion duration provides less available time for soot and NOx formations. However, only a few attempts have been made to address the effect of impingement of spray with piston walls on the emissions and combustion process. The results of model in addition to approving the corresponding data in the literature are also compared with the experimental data and shown good agreement.
3
Arai, Masataka. "Interpretative Review of Diesel Spray Penetration Normalized by Length and Time of Breakup (Similarity Law of Diesel Spray and Its Application)". Energies 15, nr 13 (5.07.2022): 4926. http://dx.doi.org/10.3390/en15134926.
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Tip penetration of diesel spray is one of the most useful parameters to evaluate diesel combustion dynamics. It has strong relationships with ignition delay, premix/diffusion combustion and engine performance, including exhaust emissions. To discuss general combustion physics in various size sprays, non-dimensional expression of spray tip penetration is reviewed. Length and time of injected fuel jet breakup can be considered as characteristic length and timescale of diesel spray. Then, normalized penetration by length and time of breakup was proposed for the scaling of various diesel sprays. Using the proposed scaling method and similarity law, tip penetrations of various size sprays are collapsed into one simple expression. It becomes a base of similarity law of diesel spray. For example, local or average A/F is uniquely expressed by the normalized length and time of breakup. Penetration of a wall impingement spray is also expressed uniquely by this normalization method and physical parameters affecting the wall impingement spray are explained. Injection rate shaping effect at an initial stage of injection is clearly demonstrated by using this scaling. Further, mixing degrees of diesel spray at an ignition timing and in a combustion phase can be reasonably explained by the equivalence ratio change with non-dimensional elapsed time after injection start.
4
Liu, Yu, Jun Li, Ying Gao i Xin Mei Yuan. "Laser Diagnostic Investigation on the Spray and Combustion with Butanol-Biodiesel-Diesel Fuel Blends". Advanced Materials Research 443-444 (styczeń 2012): 986–95. http://dx.doi.org/10.4028/www.scientific.net/amr.443-444.986.
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. In this paper, blends of butanol-biodiesel-diesel were tested inside a constant volume chamber to investigate liquid spray and combustion of the fuels. With high-speed camera and synchronized copper vapor laser, spray penetration during injection is recorded since it has a higher light reflectivity. Various ambient temperatures and fuel composition were investigated. There is a sudden drop in spray penetration at 800 K and 900 K, but not at 1000 K and 1200 K. When the spray penetration of the butanol-biodiesel-diesel blends is compared to that of the biodiesel-diesel blends, under non-combusting environment, a sudden drop in spray penetration length is also observed at 1100 K. High speed imaging shows that, for the non-combusting case, at 1100 K, the tip of the spray jet erupts into a plume sometime after injection for the butanol-biodiesel-diesel blend. The same is not seen with the biodiesel-diesel blend, neither at lower ambient temperature of 900 K. It is concluded that micro-explosion can occurs under particular conditions for the butanol-biodiesel-diesel blend, and the results is consistent with previous study in the literature.
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Chung, Wai Tong, Peter C. Ma i Matthias Ihme. "Examination of diesel spray combustion in supercritical ambient fluid using large-eddy simulations". International Journal of Engine Research 21, nr 1 (7.08.2019): 122–33. http://dx.doi.org/10.1177/1468087419868388.
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High-pressure conditions in diesel engines can often surpass the thermodynamic critical limit of the working fluid. Consequently, the injection of fuel at these conditions can lead to complex behaviors that remain only incompletely understood. This study is concerned with investigating the application of a diffuse-interface method in conjunction with a finite-rate chemistry model in large-eddy simulations of diesel spray injection and ignition in a supercritical ambient environment. The presented numerical approach offers the capability of simulating these complex conditions without the need for parameter tuning that is commonly employed in spray-breakup models. Numerical simulations of inert and reacting n-dodecane sprays — under the Engine Combustion Network Spray A and Spray D configurations — are studied, and results are compared with experimental data for liquid/vapor penetration lengths and ignition timing. In addition, parametric studies are performed to identify flow sensitivities arising from the variation in nozzle diameters between both injectors, along with the impact of low-temperature oxidation on ignition in Spray D simulations. Spray A simulations are found to be insensitive to turbulence, and predictions for penetration length and ignition behavior are in good agreement with experiments. In contrast, Spray D predictions for penetration length and ignition delay demonstrated significant sensitivities to in-nozzle turbulence, introducing uncertainty to the predicted results and stipulating the need for quantitative measurements for model evaluation.
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Xuan, Tiemin, Zhongcheng Sun, Peng Lu, Wenjun Zhong, Zhanbo Si, Zhixia He, Qian Wang, Zhou Chen i Wei Guan. "Optical study on needle lift and its effects on reacting diesel sprays of a single-hole solenoid injector". Thermal Science, nr 00 (2020): 289. http://dx.doi.org/10.2298/tsci190925289x.
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Precise control of needle lift provides one possibility to control the Diesel spray and combustion process actively. However, most studies of needle lift focus on internal flow or near nozzle spray. Little work has been performed on its effects on reacting spray. In this work, one way to change the needle lift profile of a solenoid injector has been developed and the relationship between needle lift and reacting spray has been investigated. The needle movement was detected with an optical nozzle. In addition, the visualization of reacting sprays of the same injector equipped with a single-hole nozzle was conducted in a combustion chamber. Some simulations were also performed to assist the analysis. The results show that the needle lift profile can be regulated by changing the thickness of an adjusting pad. It seems the different needle lift profiles do not bring in significant influences on reacting spray characteristics. The CFD results indicate that it is mainly caused by the similar internal flow characteristics which do not show strong variation when needle lift is higher than 0.1 mm. However, the discharge coefficient and velocity coefficient decrease sharply when needle lift is smaller than 0.05 mm because of the ?throttle? effect.
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Luo, Meng, Pingping Zhu, Usman Rana, Hu Ma, Zhendong Yu i Oskar J. Haidn. "Modeling Investigation of Liquid Oxygen Flashing Spray with CFD". Journal of Physics: Conference Series 2235, nr 1 (1.05.2022): 012061. http://dx.doi.org/10.1088/1742-6596/2235/1/012061.
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Abstract Injection of cryogenic propellants (e.g. liquid oxygen) into low-pressure environment (e.g. upper-stage rocket engine) may trigger flashing phenomenon, which severely affects the propellants’ mixing and combustion. In order to unveil the characteristics of flashing sprays, numerical models of flashing sprays were developed and validated. First, a developed model based on Adachi-correlation was employed for the flashing spray simulation. The results show good agreements with the experiments, both for the flashing spray morphology and temperature distribution. In the near-injector region, the flashing evaporation dominates the spray vaporization with the evaporation mass flow rate of about 2 orders of magnitude higher than that by the other heat transfers, whereas downstream the injector, the external heat transfer (i.e. heat conduction and convection) does. Furthermore, a new flashing spray model based on the nucleate boiling theory was proposed, which shows an improved agreement of the droplet temperature between the simulation and test data.
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Li, Zhijie, Jie Pan, Wei Li, Xiangting Wang, Haiqiao Wei i Jiaying Pan. "New Insights into Abnormal Combustion Phenomena Induced by Diesel Spray-Wall Impingement under Engine-Relevant Conditions". Energies 15, nr 8 (17.04.2022): 2941. http://dx.doi.org/10.3390/en15082941.
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High altitude and low temperature is the common extreme environment for internal combustion engines. Under such operating conditions, heavy-duty diesel engines often suffer from serious abnormal combustion, such as knocking combustion, which results in piston crown breakdown and cylinder head erosion. Spray-wall impingement and pool fires are considered potential causes; however, the detailed mechanism remains poorly understood owing to the lack of research data. In this study, for the first time, the destructive abnormal combustion induced by diesel spray-wall impingement was identified using an optical rapid compression machine under engine-relevant conditions at high altitudes. Combining instantaneous pressure and temperature measurements with simultaneously recorded high-speed photography gives useful insights into understanding the detailed combustion processes. The experimental results show that depending on the extent of diesel spray-wall impingement, supersonic detonation-like reaction fronts featuring bright luminosity can be observed. The propagation of these reaction fronts in-cylinder results in severe pressure oscillations with an amplitude approaching hundreds of atmospheres, which is like the super-knock events in boosted direct-injection spark-ignition engines. Further parametric analysis indicates that the interplay between the diffusion combustion controlled by diesel spray and the premixed combustion dominated by attached film evaporation results in the formation of abnormal combustion. Destructive reaction fronts tend to occur at a prolonged ignition delay time, which facilitates the mixing between diesel evaporation and hot air.
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Raghu, P., K. Thilagan, M. Thirumoorthy, Siddharth Lokachari i N. Nallusamy. "Spray Characteristics of Diesel and Biodiesel in Direct Injection Diesel Engine". Advanced Materials Research 768 (wrzesień 2013): 173–79. http://dx.doi.org/10.4028/www.scientific.net/amr.768.173.
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Alternative fuels for diesel engines are becoming important due to the decrease of petroleum reservoirs and the increase of environment pollution problems. The biodiesel is technically competitive with conventional petroleum-derived diesel fuel and requires no changes in the fuel distribution system. Injection process of biodiesel influences the atomization and dispersion of fuel in the combustion chamber. In diesel Engine different tests have been performed to improve the efficiency in cycle, power, less emission, speed, etc. There are various methods of visualizing the combustion chamber in a Diesel engine. For visualizing spray characteristics of combustion chamber in Diesel engine the window of 10mm diameter hole, transparent quartz glass materials are used, which can with-stand 1500°C temperature and pressure of about 1000 bar and engine is hand cranked for conducting the experiments. Spray characteristics of palm oil methyl ester (POME) and diesel were studied experimentally. Spray penetration and spray angle were measured in a combustion chamber of DI diesel engine by employing high definition video camera and image processing technique. The study shows the POME gives longer spray tip penetration and spray angle are smaller than those of diesel fuels. This is due to the viscosity and density of biodiesel.
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Duronio, Francesco, Angelo De De Vita, Alessandro Montanaro i Luigi Allocca. "Experimental Investigation and Numerical CFD Assessment of a Thermodynamic Breakup Model for Superheated Sprays with Injection Pressure up to 700 Bar". Fluids 8, nr 5 (14.05.2023): 155. http://dx.doi.org/10.3390/fluids8050155.
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Among the most relevant fields of research recently investigated for improving the performance of gasoline direct injection (GDI) engines, there are ultrahigh injection pressures and the flash-boiling phenomenon. Both perform relevant roles in improving the air/fuel mixing process, reducing tailpipe emissions and implementing new combustion methods. When a high-temperature fuel is released into an environment with a pressure lower than the fuel’s saturation pressure, flash boiling occurs. Due to complex two-phase flow dynamics and quick droplet vaporization, flash boiling can significantly modify spray formation. Specifically, if properly controlled, flash boiling produces important benefits for the fuel–air mixture formation, the combustion quality and, in general, for overall engine operation. Flash boiling was broadly investigated for classical injection pressure, but few works concern ultrahigh injection pressure. Here, the investigation of the spray produced by a multihole injector was performed using both experimental imaging techniques and CFD simulations aiming to highlight the combined impact of the injection pressure and the flash boiling occurrence on the spray morphology. The shadowgraph method was employed to observe the spray experimentally. The information gathered allows for assessing the performances of an Eulerian–Lagrangian algorithm purposely developed. Breakup and evaporation models, appropriate for flashing sprays, were implemented in a CFD (Computational Fluid Dynamics) code. The experimental results and the CFD simulations demonstrate a good agreement, demonstrating that through adoption of a flash-boiling breakup model, it is possible to reproduce non-evaporating and superheated sprays while changing few simulation parameters. Finally, the results also show the significance of injection pressure in preventing spray collapse.
11
He, Zhixia, Tiemin Xuan, Yanru Xue, Qian Wang i Liang Zhang. "A numerical study of the effects of injection rate shape on combustion and emission of diesel engines". Thermal Science 18, nr 1 (2014): 67–78. http://dx.doi.org/10.2298/tsci130810013h.
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The spray characteristics including spray droplet sizes, droplet distribution, spray tip penetration length and spray diffusion angle directly affects the mixture process of fuel and oxygen and then plays an important role for the improvement of combustion and emission performance of diesel engines. Different injection rate shapes may induce different spray characteristics and then further affect the subsequent combustion and emission performance of diesel engines. In this paper, the spray and combustion processes based on four different injection rate shapes with constant injection duration and injected fuel mass were simulated in the software of AVL FIRE. The numerical models were validated through comparing the results from the simulation with those from experiment. It was found that the dynamic of diesel engines with the new proposed hump shape of injection rate and the original saddle shape is better than that with the injection rate of rectangle and triangle shape, but the emission of NOX is higher. And the soot emission is lowest during the late injection period for the new hump-shape injection rate because of a higher oxidation rate with a better mixture between fuel and air under the high injection pressure.
12
Zhong, Shenghui, Shijie Xu, Xue-Song Bai, Ahmad Hadadpour, Mehdi Jangi, Fan Zhang, Qing Du i Zhijun Peng. "Combustion characteristics of n-heptane spray combustion in a low temperature reform gas/air environment". Fuel 293 (czerwiec 2021): 120377. http://dx.doi.org/10.1016/j.fuel.2021.120377.
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Wang, Tae-Joong, i Seung-Wook Baek. "Study on Vaporization and Combustion of Spray in High Pressure Environment". Transactions of the Korean Society of Mechanical Engineers B 27, nr 9 (1.09.2003): 1273–81. http://dx.doi.org/10.3795/ksme-b.2003.27.9.1273.
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Wang, Xian Cheng, Jun Biao Hu, Xing He i Meng Chao Guo. "Prediction and Analysis of Combustion Chamber Thermal Load of Heavy Vehicle at Different Altitudes". Advanced Materials Research 706-708 (czerwiec 2013): 1492–95. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.1492.
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For the thermal load of a heavy vehicle is too high in plateau environment, based on Hiroyasu spray model and predictive combustion model, a turbocharged diesel engine model with environmental adaptive predictive ability was established. The experimental results of 3700m revealed that the simulation result relative errors were less than 5%. The research of combustion chamber temperature field was made. This method provides a fundamental basis for further design of the combustion chamber.
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Shin, Jong-Seon, Dowon Shun, Churl-Hee Cho, Yujin Choi i Dal-Hee Bae. "The Characteristics of the After-Combustion in a Commercial CFBC Boiler Using the Solid Waste Fuel". Energies 15, nr 15 (29.07.2022): 5507. http://dx.doi.org/10.3390/en15155507.
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A CFBC (Circulating Fluidized Bed Combustor) boiler for combusted SRF (Solid Refused Fuel) is designed for solid waste combustion and power generation. The boiler consumes about 200 tons/day of SRF and generates 60 ton/h of steam or 10 MWe in electricity. The boiler is designed to burn pelletized waste fuel made of municipal solid waste collected from a town with a population of 400,000. Heat and mass balance calculations over the combustor and at each boiler section were performed and compared between the designed and measured data to analyze the boiler’s performance. After-combustion, the most significant phenomenon in low-density waste-derived fuel combustion in a CFBC boiler was monitored. The heat and mass balance were the most appropriate tools to analyze the boiler performance. The flow rate of spray water at the de-superheater was a reliable indicator to quantify the after-combustion. The design modification of the boiler unit for after-combustion control in the existing boiler was based on the quantification of spray water. The load distribution of the de-superheater decreases from 1.76% to 0.87% in 89% MCR before the installation of the evaporator and 82* % MCR load distribution of each boiler part after installation. The result was effective for the control of after-combustion in the existing boiler.
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Bari, Saiful, Chi Zhang, Fahad Kafrawi i Kang Hei Lee. "Study of Spray Behaviors to Correlate with Engine Performance and Emissions of a Diesel Engine Using Canola-Based Biodiesel". Fuels 3, nr 1 (10.02.2022): 87–112. http://dx.doi.org/10.3390/fuels3010007.
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The use of renewable biodiesel fuel in diesel engines can reduce the demand for depleting fossil fuels and reduce harmful emissions to the environment. In this research, an engine simulation is conducted using ANSYS Forte software, which allows for visualization of the spray inside the combustion chamber. The results show that biodiesel has higher liquid and vapor penetration lengths, higher droplet mass and diameter, and a longer breakup length. Molecular images of fuel molecules show that the temperature of biodiesel molecules is 141 °C lower than diesel molecules at 709 degree crank angle (°CA). These characteristics result in an extended evaporation time for biodiesel, consequently leading to poorer performance. Additionally, increased penetration length can lead to carbon deposits inside the combustion chamber. Therefore, such inefficiencies of biodiesel spray properties lead to lower combustive performance than diesel. In terms of performance, on average, biodiesel produces 16.9% lower power and 19.9% higher brake specific fuel consumption. On average, the emissions of CO, CO2, and HC of biodiesel are 17.8%, 3.41%, and 23.5% lower and NOx is 14.39% higher than the corresponding values obtained for pure diesel, respectively. In-cylinder combustion analyses show that the peak pressure of biodiesel is 0.5 MPa lower, the peak cycle temperature is 36 °C lower, the ignition delay is 4 °CA longer, the peak heat release rate is 16.5 J/deg. higher, and the combustion duration is 5.96 °CA longer compared to diesel combustion.
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FAN, XIAOFENG, i JIANGFENG WANG. "A MARKER-BASED EULERIAN-LAGRANGIAN METHOD FOR MULTIPHASE FLOW WITH SUPERSONIC COMBUSTION APPLICATIONS". International Journal of Modern Physics: Conference Series 42 (styczeń 2016): 1660159. http://dx.doi.org/10.1142/s2010194516601599.
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The atomization of liquid fuel is a kind of intricate dynamic process from continuous phase to discrete phase. Procedures of fuel spray in supersonic flow are modeled with an Eulerian-Lagrangian computational fluid dynamics methodology. The method combines two distinct techniques and develops an integrated numerical simulation method to simulate the atomization processes. The traditional finite volume method based on stationary (Eulerian) Cartesian grid is used to resolve the flow field, and multi-component Navier-Stokes equations are adopted in present work, with accounting for the mass exchange and heat transfer occupied by vaporization process. The marker-based moving (Lagrangian) grid is utilized to depict the behavior of atomized liquid sprays injected into a gaseous environment, and discrete droplet model 13 is adopted. To verify the current approach, the proposed method is applied to simulate processes of liquid atomization in supersonic cross flow. Three classic breakup models, TAB model, wave model and K-H/R-T hybrid model, are discussed. The numerical results are compared with multiple perspectives quantitatively, including spray penetration height and droplet size distribution. In addition, the complex flow field structures induced by the presence of liquid spray are illustrated and discussed. It is validated that the maker-based Eulerian-Lagrangian method is effective and reliable.
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Fang, Yuwen, Xiao Ma, Yixiao Zhang, Yanfei Li, Kaiqi Zhang, Changzhao Jiang, Zhi Wang i Shijin Shuai. "Experimental Investigation of High-Pressure Liquid Ammonia Injection under Non-Flash Boiling and Flash Boiling Conditions". Energies 16, nr 6 (18.03.2023): 2843. http://dx.doi.org/10.3390/en16062843.
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Liquid ammonia is an ideal zero-carbon fuel for internal combustion engines. High-pressure injection is a key technology in organizing ammonia combustion. Characteristics of high-pressure liquid ammonia injection is lack of research. Spray behaviors are likely to change when a high-pressure diesel injector uses liquid ammonia as its fuel. This study uses high-speed imaging with a DBI method to investigate the liquid penetration, width, and spray tip velocity of high-pressure liquid ammonia injection up to 100 MPa. Non-flash and flash boiling conditions were included in the experimental conditions. Simulation was also used to evaluate the results. In non-flash boiling conditions, the Hiroyasu model provided better accuracy than the Siebers model. In flash boiling conditions, a phenomenon was found that liquid penetration and spray tip velocity were strongly suppressed in the initial stage of the injection process, this being the “spray resistance phenomenon”. The “spray resistance phenomenon” was observed when ambient pressure was below 0.7 MPa during 0–0.05 ms ASOI and was highly related to the superheated degree. The shape of near-nozzle sprays abruptly changed at 0.05 ms ASOI, indicating that strong cavitation inside the nozzle caused by needle lift effects is the key reason for the “spray resistance phenomenon”.
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Cengiz, Cengizhan, i Salih Ozen Unverdi. "A CFD Study on the Effects of Injection Timing and Spray Inclusion Angle on Performance and Emission Characteristics of a DI Diesel Engine Operating in Diffusion-Controlled and PCCI Modes of Combustion". Energies 16, nr 6 (20.03.2023): 2861. http://dx.doi.org/10.3390/en16062861.
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In three-dimensional (3D) computational fluid dynamics (CFD) simulations, the effects of injection timing and spray inclusion angle (SIA) on performance and emissions of diffusion-controlled and Premixed Charge Compression Ignition (PCCI) combustion in part load for a heavy-duty direct injection (HDDI) diesel engine are studied. The start of injection (SOI) of a 146° SIA injector is varied between −70 and −10 °crank angle (°CA) after top dead center (ATDC). For −50 °CA ATDC SOI with various SIAs between 80° and 146°, PCCI combustion reduces mono-nitrogen oxide (NOx) emissions significantly compared to conventional diesel combustion (CDC). Due to incomplete combustion in rich zones formed by droplet–cylinder wall interaction, early wide SIA injection deteriorates combustion efficiency (CE) and Indicated Mean Effective Pressure (IMEP) and increases soot and carbon monoxide (CO) emissions. Narrow-angle sprays interacting with the piston bowl elevate CE and IMEP and decrease soot and CO emissions but increases NOx emissions. Optimal combustion is achieved by avoiding fuel droplet–cylinder wall interaction. By spray-targeting at the stepped lip of the piston bowl, 100° SIA and −50 °CA ATDC SOI yield, respectively, the highest CE and IMEP: 97.8% and 3.37 bar and the lowest soot and CO emissions: 33.5 and 2.2 ppm, with acceptable NOx emissions.
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Wang, Chengguan, Xiaozhi Qi, Tao Wang, Diming Lou, Piqiang Tan, Zhiyuan Hu, Liang Fang i Rong Yang. "Role of Altitude in Influencing the Spray Combustion Characteristics of a Heavy-Duty Diesel Engine in a Constant Volume Combustion Chamber. Part I: Free Diesel Jet". Energies 16, nr 12 (20.06.2023): 4832. http://dx.doi.org/10.3390/en16124832.
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Heavy-duty diesel engines operating in plateau regions experience deteriorated combustion. However, the lack of up-to-date information on the spray-combustion process limits the fundamental understanding of the role of altitude. In this work, the in-cylinder thermodynamic conditions of a real diesel engine operating under different altitudes were reproduced in a constant-volume combustion chamber (CVCC). The liquid spray, ignition, and combustion processes were visualized in detail using different optical diagnostics. Apart from predictable results, some interesting new findings were obtained to improve the understanding of free spray-combustion processes with different altitudes. The spatial distributions of ignition kernels provided direct evidence of higher peak pressure rise rates for high-altitude diesel engines. The percent of stoichiometric air was calculated to confirm that the net effect of altitude was an increase in the amount of air-entrained upstream of the lifted flame; therefore, the soot levels deduced from flame images were inconsistent with those from real engines, revealing that accelerating the soot oxidation process could effectively reduce engine soot emissions in plateau regions. Finally, a novel schematic diagram of the spray flame structure was proposed to phenomenologically describe the role of altitude in influencing the spray-combustion process of a free jet.
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Nagareddy, Shivakumar, i Kumaresan Govindasamy. "Combustion chamber geometry and fuel supply system variations on fuel economy and exhaust emissions of GDI engine with EGR". Thermal Science 26, nr 2 Part A (2022): 1207–17. http://dx.doi.org/10.2298/tsci211020358n.
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In this study, the combustion chamber geometry for spray-guided, wall-guided, and air-guided combustion strategies were fabricated. The piston crown shape and the cylinder head in each combustion chamber geometry was machined by fixing the fuel injector and spark plug at proper positions to obtain swirl, turbulence, and squish effects for better mixing of fuel with air and superior combustion of the mixture. Conducted tests on all the three modified gasoline direct injection engines with optimized exhaust gas recirculation and electronic control towards fuel injection timing, the fuel injection pressure, and the ignition timing for better the performance and emissions control. It is clear from the results that NOx emissions from all three combustion modes were reduced by 4.9% up to 50% of loads and it increase for higher loads due to increase of in-cylinder pressure. The fuel consumption and emissions showed better at 150 bar fuel injection pressure for wall-guided combustion chamber geometry. Reduced HC emissions by 3.7% and 4.7%, reduced CO emissions by 2% and 3.3%, reduced soot emissions by 6.12% and 10.6%. Reduces specific fuel consumption by about 10.3% and 13.3% in wall-guided combustion strategy compare with spray-guided and air-guided combustion modes respectively
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Xie, Kai, Jie Zhang, Changlin Qin, Xiufeng Tan i Yunjing Cui. "Numerical study on flame and emission characteristics of a small flue gas self-circulation diesel burner with different spray cone angles". Thermal Science, nr 00 (2021): 150. http://dx.doi.org/10.2298/tsci201229150x.
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The problems of long flame and high pollution emissions in low-power burners are of wide concern in small heating devices. To solve this problem, a small diesel burner with self-circulation flue gas was designed herein. In order to obtain a deeper scientific understanding of the flame and emission characteristics of the burner with different spray cone angles, a numerical calculation method was used to investigate them. Reasonable flow, heat transfer, and combustion models were selected, and periodic boundary conditions were used to verify the feasibility of the numerical model. The results indicate that the flame length increases with increasing spray cone angle, and then the flame length basically stabilizes at 410 mm. The maximum flame temperature decreases slightly with increasing spray cone angle. Besides this, the NO emission of this small flue gas self-circulation burner decreases with increasing spray cone angle and is as low as 10 ppm at an 80? spray cone angle. In addition, the influence mechanism of the spray cone angle on the flue gas self-circulation ratio was analyzed from the physical aspect of the spray area and the chemical aspect of combustion. This study is of great significance to research on the flame morphology of small flue gas self-circulation burners and the selection of different spray cone angles.
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Wang, Jun, Yan Kang, Lin Yang, Xiaolu Li i Tianhong Yan. "Study on biodiesel heat transfer through self-temperature limit injector during vehicle cold start". Thermal Science 19, nr 6 (2015): 1907–18. http://dx.doi.org/10.2298/tsci141011177w.
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A type of Self-Temperature Limit-Injector (STL- injector) is proposed to reduce the biodiesel consumption and emission in vehicle cold start process. The STL-injector is capable of fast raising fuel temperature, which helps improve the quality of diesel spray and its combustion efficiency. A STL-injector model is established with consideration of electro-mechanic coupling and fluid-structure interaction. A transient simulation is conducted using dynamic grid technology. The results show that STL-injector can effectively raise biodiesel temperature to 350K from 300K in 32 seconds. That is to say, adding STL-injector to existing biodiesel combustion system is an environment-friendly solution due to improving atomization and spray quality quickly.
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Singh, Rahul Kumar. "Investigation of Diesel Engine Combustion Characteristics for Varying Nozzle Depth at Different Spray Angles". ECS Transactions 107, nr 1 (24.04.2022): 9265–74. http://dx.doi.org/10.1149/10701.9265ecst.
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The demand for petroleum-derived fuels is increasing every day despite their speculations about the exhaustion of petroleum fuel. Petroleum-derived fuels are classified as a suspect element for humans due to their known primary adverse effects on the environment. The concern is that the demand for petroleum fuel will rise along with the market price. Researchers around the world focus on reducing the harmful effects of petroleum fuel or finding some other substitute for petroleum fuels. A Kirloskar single cylinder diesel engine (model TV-1) was selected for simulation using commercially available AVL FIRE software. The published articles indicate the operating conditions and limitations of the single cylinder diesel engine. The geometry of the hemispherical cup piston is generated and networked in software, then the search is processed by selecting three different spray angles, such as 120o, 140o, and 160o. The standard spray angle is 120o. In addition, four nozzle depths are included in the search to analyze the effect of nozzle depth on combustion parameters. The nozzles are available in four depths: 0.5 mm, 1 mm, 1.5 mm, and 2 mm. while the nozzle depth is 1 mm standard nozzle depth. Four nozzle depths with spray angles of 120°, 140°, and 160° are examined. The results returned the combustion parameter and depend on the spray angle and the depth of the nozzle. To obtain an adequate combustion result from the above scenario, some trade-offs in terms of combustion parameters need to be considered.
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Ouellette, Laura, i Vladimir Razbin. "REMEDIATION OF OIL-CONTAMINATED DEBRIS USING A ROTARY KILN COMBUSTOR". International Oil Spill Conference Proceedings 1995, nr 1 (1.02.1995): 958–59. http://dx.doi.org/10.7901/2169-3358-1995-1-958.
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ABSTRACT The Emergencies Engineering Division (EED) of Environment Canada's Environmental Technology Centre has been investigating the use of combustion to remediate oil-contaminated debris resulting from marine oil spills. Rotary kiln technology was determined to be suitable for such wastes, and offers an environmentally safe solution to this problem. The debris used for these tests were oil-contaminated gravel and sorbents. The rotary kiln tests were conducted at the Energy Research Laboratory, CANMET, Natural Resources Canada between January and February 1994. The system consists of the rotary kiln combustor, feed systems, afterburner, and packed bed spray tower, induced draft fan, and stack.
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Datta, A., i S. K. Som. "Effects of spray characteristics on combustion performance of a liquid fuel spray in a gas turbine combustor". International Journal of Energy Research 23, nr 3 (10.03.1999): 217–28. http://dx.doi.org/10.1002/(sici)1099-114x(19990310)23:3<217::aid-er473>3.0.co;2-u.
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Kim, Namsu, Kiyoung Jung i Yongmo Kim. "Multi-environment PDF modeling for n-dodecane spray combustion processes using tabulated chemistry". Combustion and Flame 192 (czerwiec 2018): 205–20. http://dx.doi.org/10.1016/j.combustflame.2018.02.004.
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Ganji, Prabhakara, Rajesh Raju i Srinivasa Rao. "Computational optimization of biodiesel combustion using response surface methodology". Thermal Science 21, nr 1 Part B (2017): 465–73. http://dx.doi.org/10.2298/tsci161229031g.
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The present work focuses on optimization of biodiesel combustion phenomena through parametric approach using response surface methodology. Physical properties of biodiesel play a vital role for accurate simulations of the fuel spray, atomization, combustion, and emission formation processes. Typically methyl based biodiesel consists of five main types of esters: methyl palmitate, methyl oleate, methyl stearate, methyl linoleate, and methyl linolenate in its composition. Based on the amount of methyl esters present the properties of pongamia bio-diesel and its blends were estimated. CONVERGETM computational fluid dynamics software was used to simulate the fuel spray, turbulence and combustion phenomena. The simulation responses such as indicated specific fuel consumption, NOx, and soot were analyzed using design of experiments. Regression equations were developed for each of these responses. The optimum parameters were found out to be compression ratio ? 16.75, start of injection ? 21.9? before top dead center, and exhaust gas re-circulation ? 10.94%. Results have been compared with baseline case.
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Li, Zhipeng, Qiang Zhang, Fujun Zhang, Hongbo Liang i Yu Zhang. "Investigation of Effect of Nozzle Numbers on Diesel Engine Performance Operated at Plateau Environment". Sustainability 15, nr 11 (25.05.2023): 8561. http://dx.doi.org/10.3390/su15118561.
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The effect of nozzle number on the combustion and emission characteristics of diesel engines operating at high altitudes was investigated in this study. A three-dimensional computational fluid dynamics model was developed to simulate the spray spatial distribution, which is closely related to the nozzle number. The intake pressure was identified as the dominant factor under varying altitudes, while the fuel mass, injection timing and temperature were maintained constant. Altitudes of 3000 m were chosen to represent typical high-altitude conditions, and sea level cases were simulated for comparison. The results demonstrated that high-altitude operation reduced the air utility in the combustion chamber, leading to suppressed soot oxidization and worse soot emissions. Moreover, more injection nozzles will decrease the fuel injection pressure, resulting in inadequate fuel diffusion and detrimental effects on the combustion efficiency and soot control. However, too few nozzles may cause wall collisions and worsen the combustion conditions. The number of nozzles also influences the combustion, with a higher number of nozzles exacerbating poor combustion conditions. The optimal number of nozzles for the engine studied is determined to be six. Hence, determining the optimal nozzle number plays a vital role in achieving the optimal performance of highland diesel engines. This study provides valuable guidance for the development of diesel engines in high-altitude environments, where controlling the fuel consumption and soot emissions is challenging.
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Poursadegh, Farzad, Oleksandr Bibik, Boni Yraguen i Caroline L. Genzale. "A multispectral, extinction-based diagnostic for drop sizing in optically dense diesel sprays". International Journal of Engine Research 21, nr 1 (31.07.2019): 15–25. http://dx.doi.org/10.1177/1468087419866034.
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Diesel sprays present a challenging environment for detailed quantitative measurement of the liquid field, and to date, there have been only a few efforts to characterize drop sizes within the family of Engine Combustion Network (ECN) diesel sprays. Drop sizing diagnostics, including optical microscopy and Ultra-Small Angle X-ray Scattering (USAXS), have been recently demonstrated in Spray A/D ECN activities, but little data exist to validate these results. This work therefore seeks to extend the available ECN data on the liquid phase field and provide a new comparative data set for assessment of previous ECN drop sizing measurements. In particular, this work presents the development of a two-wavelength, line-of-sight extinction measurement to examine liquid volume fraction and the corresponding droplet field in high-pressure fuel sprays. Here, extinction of lasers emitting at 10.6 μm and 0.633 μm are used for the measurement. To enable quantification of the liquid field in optically dense regions of the spray, a transfer function is developed to account for the influence of multiple scattering. The developed diagnostic is then applied to n-dodecane sprays from the ECN Spray A and Spray D injectors at varying fuel rail pressures and atmospheric chamber condition. Overall, the results show a reasonable agreement with droplet sizes measured using USAXS, as well as from more recent measurements using a Scattering-Absorption Measurement Ratio (SAMR) technique also developed in our group. This is particularly the case near the spray periphery, where on average, less than 40% difference in the measured Sauter mean diameter is observed. Nonetheless, an apparent discrepancy is observed between drop sizes from different diagnostics close to the jet centerline (i.e. nearly 100% difference between available data for Spray D injector). Moreover, the presented diagnostic shows an improved capability in the dilute regions of the spray, where x-ray-based diagnostics are generally subject to high noise and low signal sensitivity.
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Lee, Hyungmin. "Spray, Combustion, and Air Pollutant Characteristics of JP-5 for Naval Aircraft from Experimental Single-Cylinder CRDI Diesel Engine". Energies 14, nr 9 (21.04.2021): 2362. http://dx.doi.org/10.3390/en14092362.
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This study was performed to analyze the spray, combustion, and air pollutant characteristic of JP-5 fuel for naval aircraft in a spray visualization system and a single-cylinder CRDI diesel engine that can be visualized. The analysis results of JP-5 fuel were compared with DF. The spray tip penetration of JP-5 showed diminished results as the spray developed. JP-5 had the highest ROHR and ROPR regardless of the fuel injection timings. The physicochemical characteristics of JP-5, such as its excellent vaporization and low cetane number, were analyzed to prolong the ignition delay. Overall, the longer combustion period and the lower heat loss of the DF raised the engine torque and the IMEP. JP-5 showed higher O2 and lower CO2 levels than the DF fuel. The CO emission level increased as the injection timing was advanced in two test fuels, and the CO emitted from the DF fuel, which has a longer combustion period than JP-5, turned out to be lower. NOx also reduced as the fuel injection timing was retarded, but it was discharged at a higher level in JP-5 due to the large heat release. The images from the combustion process visualization showed that the flame luminosity of DF is stronger, its ignition delay is shorter, and its combustion period is longer than that of JP-5.
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Payri, Raul, Pedro Marti-Aldaravi, Rami Abboud i Abian Bautista. "Numerical Analysis of GDI Flash Boiling Sprays Using Different Fuels". Energies 14, nr 18 (18.09.2021): 5925. http://dx.doi.org/10.3390/en14185925.
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Modeling the fuel injection process in modern gasoline direct injection engines plays a principal role in characterizing the in–cylinder mixture formation and subsequent combustion process. Flash boiling, which usually occurs when the fuel is injected into an ambient pressure below the saturation pressure of the liquid, is characterized by fast breakup and evaporation rates but could lead to undesired behaviors such as spray collapse, which significantly effects the mixture preparation. Four mono–component fuels have been used in this study with the aim of achieving various flashing behaviors utilizing the Spray G injector from the Engine Combustion Network (ECN). The numerical framework was based on a Lagrangian approach and was first validated for the baseline G1 condition. The model was compared with experimental vapor and liquid penetrations, axial gas velocity, droplet sizes and spray morphology and was then extended to the flash boiling condition for iso–octane, n–heptane, n–hexane, and n–pentane. A good agreement was achieved for most of the fuels in terms of spray development and shape, although the computed spray morphology of pentane was not able to capture the spray collapse. Overall, the adopted methodology is promising and can be used for engine combustion modeling with conventional and alternative fuels.
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Mai, Zhaoming, Yang Liu, Chenglong Tang i Zuohua Huang. "Experimental Investigation on Auto-Ignition Characteristics of Kerosene Spray Flames". Machines 10, nr 8 (22.07.2022): 601. http://dx.doi.org/10.3390/machines10080601.
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To facilitate the better use of RP-3 kerosene in compression ignition engines, the auto-ignition behaviors of RP-3 kerosene spray were experimentally investigated in an optical rapid compression machine. Results show that most of the tests have good ignitability and combustion performance. For all the successful ignited cases, the flame kernel was found to be formed before the steep rise of pressure, which explained that image-based ignition delay time is always shorter than the pressure-based ignition delay time. The effects of ambient environment, injection pressure, and injection delay time on the pressure history, ignition intensity, combustion duration, heat release rate, and other parameters were investigated individually. The ambient environment has a strong influence on ignition delay time by accelerating the chemical reactions, whereas the high injection pressure helps the better vaporization of fuel spray. The effect of injection delay time is non-monotonic as the trade-off relation between heat loss and blending of fuel and oxygen. The heat release rate histories under different conditions were compared and analyzed, and the two-stage heat release phenomenon was observed in the negative temperature coefficient region. The ignition intensity region was determined based on the measured ignition delay times of RP-3 kerosene spray, and multiple linear regression correlation was used to study the ignition delay time sensitivity to multi-factors.
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Khatamnezhad, Hassan, Shahram Khalilarya, Samad Jafarmadar i Arash Nemati. "Incorporation of EGR and split injection for reduction of nox and soot emissions in DI diesel engines". Thermal Science 15, suppl. 2 (2011): 409–27. http://dx.doi.org/10.2298/tsci100317019k.
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In this paper, reduced temperature combustion has been investigated at high load condition of a DI diesel engine. A three dimensional CFD model for flow field, spray, air-fuel mixture formation, combustion and emissions formation processes have been used to carry out the computations. The combined effect of EGR temperature and EGR rate was analyzed to choose with consideration of engine performance. Then, the influence of different injection rates and split injection was explored at a reduced temperature combustion condition by the use of EGR. The results represent sensitiveness of various injection schemes on the combustion process and emission formation at reduced temperature condition in DI diesel engines.
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Du, Wei, Qiankun Zhang, Meng Li i Jinchi Hou. "Ignition and combustion characteristics of wall-impinged kerosene (RP-3) fuel spray with varying injection parameters". Thermal Science 24, nr 1 Part A (2020): 171–81. http://dx.doi.org/10.2298/tsci190118169d.
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The fuel quantity and injection pressure are two essential factors to optimize the injection strategy. In this paper, we focus on the investigation for the ignition and combustion characteristics of wall-impinged kerosene (RP-3) fuel spray at different injection quantities and pressures. Experiments are conducted in a constant volume combustion vessel to simulate the Diesel engine condition, adopting a single-hole nozzle with 0.22 mm. The flame images are captured using a high-speed camera, and then the behaviors of ignition and combustion are processed and analyzed. The main emphasis is placed on the variation laws of the ignition position distance, the ignition delay time, the combustion duration, the flame area, spatially integrated natural luminosity and time integrated natural luminosity.
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Xie, Kai, Xingqi Qiu, Yunjing Cui i Jianxin Wang. "Experimental study on the effect of spray cone angle on the characteristics of horizontal jet spray flame under sub-atmospheric pressure". Thermal Science 24, nr 5 Part A (2020): 2941–52. http://dx.doi.org/10.2298/tsci181106014x.
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The burning state of a plateau environment is attracting more and more attention. In this paper, in order to have a deeper scientific understanding of diesel spray combustion and the characteristics of a flame under different spray cone angles in a plateau environment, experiments were carried out in a low pressure chamber. The flame morphology was recorded by a high speed video instrument, and the temperature change was recorded by a thermal imager and thermocouples. The MATLAB programming was used to process the video image of the flame, and the probability of its binarization was calculated. The results indicate that the flame becomes longer and wider under different pressures with the same spray angle. The variation is more pronounced at a smaller spray taper angle. The flame uplifted height characteristic is mainly negatively related to the atmospheric pressure. According to the normalized flame temperature and the dimensionless horizontal projection, the length can be divided into three regions. In the region of buoyancy flame, the dimensionless temperature varies with sub-atmospheric pressure more than with normal pressure. In addition, under different spray cone angle conditions, the law of variation in the normalized flame temperature under sub-atmospheric pressure is exactly opposite to that under normal pressure. This study is of great significance to the scientific research on flames in a low pressure environment, and the design of different fuel nozzles for application in a plateau environment.
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Csemány, Dávid, i Viktor Józsa. "A Two-Parameter Corresponding States Method for Calculating the Steady-State Evaporation Rate of C2–C9 n-Alkane Droplets in Air for Elevated Pressures and Temperatures". Flow, Turbulence and Combustion 107, nr 2 (12.01.2021): 283–305. http://dx.doi.org/10.1007/s10494-020-00238-7.
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AbstractAdvanced gas turbine and internal combustion engine combustion chambers operate at highly elevated pressures and temperatures. Therefore, spray vaporization analysis cannot be limited to the atmospheric environment since evaporation strongly depends on ambient conditions. Presently, the effect of air pressure and temperature on droplet evaporation rate was investigated by using both a transient and a steady-state approach. A corresponding states model was derived for the steady-state evaporation rate for n-alkanes in the range of C2–C9 with an excellent fit quality and < 1% model uncertainty, considering the thermophysical data uncertainties. The model was tested for C1, C10, and C12 n-alkanes as well with low success. The ambient conditions were evaluated in terms of reduced pressures and temperatures, covering the range of 0.02–0.5 and 1.2–1.5, respectively. However, the applicability of the model was limited to reduced temperature of 1.3–1.5, as higher discrepancy was observed between the trends of the different n-alkanes at lower temperatures. Since the heat-up phase of practical sprays in combustion chambers is often short, the present model might significantly reduce the computational effort required for liquid evaporation calculations.
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Liu, Fushui, Ziming Yang, Yikai Li i Han Wu. "Experimental study on the combustion characteristics of impinging diesel spray at low temperature environment". Applied Thermal Engineering 148 (luty 2019): 1233–45. http://dx.doi.org/10.1016/j.applthermaleng.2018.12.016.
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Watanabe, Hirotatsu, Yoshikazu Suwa, Yohsuke Matsushita, Yoshio Morozumi, Hideyuki Aoki, Shoji Tanno i Takatoshi Miura. "Spray combustion simulation including soot and NO formation". Energy Conversion and Management 48, nr 7 (lipiec 2007): 2077–89. http://dx.doi.org/10.1016/j.enconman.2007.01.008.
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Mao, Jun Yuan, i Wei Gang Zheng. "Research on Laser Remelting of Plasma Sprayed Ceramic Nanometer Coatings on the Inner Wall of the Cylinder Liner". Advanced Materials Research 912-914 (kwiecień 2014): 301–4. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.301.
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The Cylinder liner is one of the working environment of the worst parts in internal combustion engine ,it is required to have good wear resistance, corrosion resistance, resistance to high temperature and high pressure shock, etc. After tests showed, better comprehensive mechanical properties of cylinder liner is got by using Plasma Spray composite ceramic nanometer coating technology, and after laser remelting treatment.
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Baek, Hyun Min, i Hyung Min Lee. "Spray Behavior, Combustion, and Emission Characteristics of Jet Propellant-5 and Biodiesel Fuels with Multiple Split Injection Strategies". Energies 15, nr 7 (30.03.2022): 2540. http://dx.doi.org/10.3390/en15072540.
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This study focuses on an analysis of the spray behavior, combustion, and emission characteristics of jet propellant-5 (JP-5) and biodiesel fuels with single-injection timing and multiple split injection strategies in a common rail direct injection (CRDI) single-cylinder diesel engine system. The analysis includes visualization of the spray and combustion. Multiple split injection strategies (e.g., double, triple, quadruple, and quintuple) were considered by equally distributing the fuel injection amount within the single-injection. Injection of biodiesel has a delayed start (0.2 ms) as well as shorter spray tip penetration compared with JP-5. As the fuel injection timing was approached to the top dead center (TDC), the engine performance and combustion efficiency improved. Retarding the injection timing contributed to an increase in carbon dioxide (CO2) (JP-5: max. 2.6% up, BD100: max. 1.5% up) and a decrease in carbon monoxide (CO) (JP-5: max. 93% down, BD100: max. 91% down) and nitrogen oxides (NOx) (JP-5: max. 83% down, BD100: max. 82% down). In comparison with JP-5, biodiesel showed disadvantages from the point of its combustion and emission characteristics for all injection timings. The quadruple-injection strategy, in which fuel injection was performed four times, showed excellent combustion, engine performance, and combustion efficiency. The CO2 emissions were highest with the quadruple-injection strategy (JP-5: 6.6%, BD100: 5.8%). The CO emissions of biodiesel decreased as the pulses of split injection extended, and a significant reduction of 83.8% was observed. NOx increased as the number of split injections increased (JP-5: max. 37% up, BD100: max. 52% up). JP-5 was a longer ignition delay than that of biodiesel from combustion flame visualization results. The final combustion in the multiple-injection strategy showed a typical diffusion combustion pattern.
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Kawahara, Hideo, Konosuke Furukawa, Koichiro Ogata, Eiji Mitani i Koji Mitani. "Experimental Study on the Stabilization Mechanism of Diffusion Flames in a Curved Impinging Spray Combustion Field in a Narrow Region". Energies 14, nr 21 (1.11.2021): 7171. http://dx.doi.org/10.3390/en14217171.
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HVAF (High Velocity Air Flame) flame spraying can generate supersonic high-temperature gas jets, enabling thermal spraying at unprecedented speeds. However, there is a problem with the energy cost of this device. This study focused on combustors that used cheap liquid fuel (kerosene) as the fuel for HVAF. In this research, we have developed a compact combustor with a narrow channel as a heat source for the HVAF heat atomizer. Using this combustor, the stability of the flame formed in the combustor, the morphology of the flame, and the temperature behavior in the combustion chamber were investigated in detail. As a result, the magnitude of the swirling airflow had a great influence on the structure of the flame formed in the combustor, and the stable combustion range of the combustor could be determined. As the swirling air flow rate changes, the equivalent ratio of the entire combustor changes significantly, and the flame structure also transition from the premixed flame to the diffusion flame. From this study, it was confirmed that the temperature inside the combustor has great influence on the flame structure.
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Ziółkowski, Paweł, Stanisław Głuch, Piotr Józef Ziółkowski i Janusz Badur. "Compact High Efficiency and Zero-Emission Gas-Fired Power Plant with Oxy-Combustion and Carbon Capture". Energies 15, nr 7 (1.04.2022): 2590. http://dx.doi.org/10.3390/en15072590.
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Reduction of greenhouse gases emissions is a key challenge for the power generation industry, requiring the implementation of new designs and methods of electricity generation. This article presents a design solution for a novel thermodynamic cycle with two new devices—namely, a wet combustion chamber and a spray-ejector condenser. In the proposed cycle, high temperature occurs in the combustion chamber because of fuel combustion by pure oxygen. As a consequence of the chemical reaction and open water cooling, a mixture of H2O and CO2 is produced. The resulting working medium expands in one turbine that combines the advantages of gas turbines (high turbine inlet temperatures) and steam turbines (full expansion to vacuum). Moreover, the main purpose of the spray-ejector condenser is the simultaneous condensation of water vapour and compression of CO2 from condensing pressure to about 1 bar. The efficiency of the proposed cycle has been estimated at 37.78%. COM-GAS software has been used for computational flow mechanics simulations. The calculation considers the drop in efficiency due to air separation unit, carbon capture, and spray-ejector condenser processes. The advantage of the proposed cycle is its compactness that can be achieved by replacing the largest equipment in the steam unit. The authors make reference to a steam generator, a conventional steam condenser, and the steam-gas turbine. Instead of classical heat exchanger equipment, the authors propose non-standard devices, such as a wet combustion chamber and spray-ejector condenser.
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Jiang, Tsung Leo, i Huei-Huang Chiu. "Combustion of a Fuel Droplet Surrounded by Oxidizer Droplets". Journal of Heat Transfer 113, nr 4 (1.11.1991): 959–65. http://dx.doi.org/10.1115/1.2911228.
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The interaction between a burning fuel droplet and satellite oxidizer droplets is studied analytically. The effects of droplet spacing and droplet size ratio on the flame configuration of a burning fuel droplet with a satellite oxidizer droplet are analyzed in a high-temperature oxidizing environment by using the bispherical coordinate system. Three combustion modes including normal combustion, conjugate combustion, and composite combustion are identified at appropriate droplet size ratio and droplet spacing. The burning rate of the fuel droplet is found to be greater than that of an isolated burning fuel droplet, and to increase with the decreasing distance between two droplets. This result has shown a positive effect on the interaction between fuel and oxidizer droplets, in contrast to that of two interacting fuel droplets where the burning rate decreases with decreasing droplet spacing. The combustion configuration of a fuel droplet surrounded by six satellite oxidizer droplets symmetrically is also examined by the method of images. The flame that encloses the fuel droplet is found to be “compressed” and distorted to a nonspherical shape due not only to the group effect among oxidizer droplets but also to the interaction of bipropellant droplets. The results indicate that the burning rate of a fuel droplet increases and the flame size decreases significantly as a result of an increased supply of oxidizer vapor provided by the surrounding oxidizer droplets. Therefore properly optimized bipropellant combustion is potentially able to achieve a desired combustion performance with a much smaller combustor than a conventional spray burner.
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Haq, Muteeb Ul, Ali Turab Jafry, Saad Ahmad, Taqi Ahmad Cheema, Munib Qasim Ansari i Naseem Abbas. "Recent Advances in Fuel Additives and Their Spray Characteristics for Diesel-Based Blends". Energies 15, nr 19 (4.10.2022): 7281. http://dx.doi.org/10.3390/en15197281.
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The spray characteristics play a crucial role in determining the performance and emissions of compression ignition (CI) engines at the pre-combustion stage. With the advent of many types of alternative fuels and their blends with diesel, it is necessary to investigate the effect of fuel properties and various injection conditions to determine the penetration length, spray cone angle and spray area for a viable fuel with similar or better dispersion characteristics to diesel. Hence, this study reviews and summarizes the spray visualization techniques, along with in depth analysis of macroscopic spray properties of various fuel blends with diesel. It was found that higher injection pressures typically led to higher penetration lengths, better atomization with reduced Sauter mean diameter. Liquid properties such as viscosity, surface tension, and evaporation as well as structural properties play a crucial role in spray formation in fuel blends with various types of alcohols, ethers, biodiesel, aliphatic, aromatic, as well as nanoparticle additives. This review compares these fuel additives and their types to present a comparative study with diesel to determine the ideal conditions with minimal changes to the engine for replacing diesel with a sustainable fuel consisting of better combustion efficiency due to its enhanced spray characteristics.
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Chatelier, Adrien, Benoît Fiorina, Vincent Moureau i Nicolas Bertier. "Large Eddy Simulation of a Turbulent Spray Jet Flame Using Filtered Tabulated Chemistry". Journal of Combustion 2020 (19.03.2020): 1–23. http://dx.doi.org/10.1155/2020/2764523.
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This work presents Large Eddy Simulations of the unconfined CORIA Rouen Spray Burner, fed with liquid n-heptane and air. Turbulent combustion modeling is based on the Filtered TAbulated Chemistry model for LES (F-TACLES) formalism, designed to capture the propagation speed of turbulent stratified flames. Initially dedicated to gaseous combustion, the filtered flamelet model is challenged for the first time in a turbulent spray flame configuration. Two meshes are employed. The finest grid, where both flame thickness and wrinkling are resolved, aims to challenge the chemistry tabulation procedure. At the opposite the coarse mesh does not allow full resolution of the flame thickness and exhibits significant unresolved contributions of subgrid scale flame wrinkling. Both LES solutions are extensively compared against experimental data. For both nonreacting and reacting conditions, the flow and spray aerodynamical properties are well captured by the two simulations. More interesting, the LES predicts accurately the flame lift-off height for both fine and coarse grid conditions. It confirms that the modeling methodology is able to capture the filtered turbulent flame propagation speed in a two-phase flow environment and within grid conditions representative of practical applications. Differences, observed for the droplet temperature, seem related to the evaporation model assumptions.
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Boussouara, Karima, i Mahfoud Kadja. "Empirical soot formation and oxidation model". Thermal Science 13, nr 3 (2009): 35–46. http://dx.doi.org/10.2298/tsci0903035b.
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Modelling internal combustion engines can be made following different approaches, depending on the type of problem to be simulated. A diesel combustion model has been developed and implemented in a full cycle simulation of a combustion, model accounts for transient fuel spray evolution, fuel-air mixing, ignition, combustion, and soot pollutant formation. The models of turbulent combustion of diffusion flame, apply to diffusion flames, which one meets in industry, typically in the diesel engines particulate emission represents one of the most deleterious pollutants generated during diesel combustion. Stringent standards on particulate emission along with specific emphasis on size of emitted particulates have resulted in increased interest in fundamental understanding of the mechanisms of soot particulate formation and oxidation in internal combustion engines. A phenomenological numerical model which can predict the particle size distribution of the soot emitted will be very useful in explaining the above observed results and will also be of use to develop better particulate control techniques. A diesel engine chosen for simulation is a version of the Caterpillar 3406. We are interested in employing a standard finite-volume computational fluid dynamics code, KIVA3V-RELEASE2.
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Guo, Genmiao, Zhixia He, Xicheng Tao, Shenxin Sun, Zhen Zhou i Xiongbo Duan. "Optical experiments of string cavitation in diesel injector tapered nozzles". Thermal Science 24, nr 1 Part A (2020): 193–201. http://dx.doi.org/10.2298/tsci180405005g.
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Flow inside the diesel nozzle is crucial to spray, combustion, and emissions. This work aimed to improve the understanding of effects of internal fuel-flow on diesel spray, especially the special string cavitating flow. Optical experiments were employed for characterizing the formation of string cavitation inside the transparent scaled-up tapered diesel orifices. Simultaneously, the corresponding evolution of spray cone angles were obtained. Results show that there were two origins of the string cavitation, which were originated from inlet and outlet of the orifice, respectively. Moreover, there were two typical development processes of the string cavitation between hole and hole, which were defined as type-A and type-B string cavitation. Furthermore, effects of string cavitation were analyzed: it could trigger the geometry-induced cavitation and make a sharp increase of spray cone angle. Finally, the relationships between the occurrence regularity of string cavitation, the needle lift and the injection pressure were revealed by comparison of different needle lifts and different injection pressures.
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Liu, Yu, Jun Li i Chao Jin. "Fuel spray and combustion characteristics of butanol blends in a constant volume combustion chamber". Energy Conversion and Management 105 (listopad 2015): 1059–69. http://dx.doi.org/10.1016/j.enconman.2015.08.047.
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Djamari, Djati Wibowo, Muhammad Idris, Permana Andi Paristiawan, Muhammad Mujtaba Abbas, Olusegun David Samuel, Manzoore Elahi M. Soudagar, Safarudin Gazali Herawan i in. "Diesel Spray: Development of Spray in Diesel Engine". Sustainability 14, nr 23 (29.11.2022): 15902. http://dx.doi.org/10.3390/su142315902.
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Research and development in the internal combustion engine (ICE) has been growing progressively. Issues such as air pollution, fuel cost, and market competitiveness have driven the automotive industry to develop and manufacture automobiles that meet new regulation and customers’ needs. The diesel engine has some advantages over the gasoline or spark ignition engine, including higher engine efficiency, greater power output, as well as reliability. Since the early stage of the diesel engine’s development phase, the quest to obtain better atomization, proper fuel supply, and accurate timing control, have triggered numerous innovations. In the last two decades, owing to the development of optical technology, the visualization of spray atomization has been made possible using visual diagnostics techniques. This advancement has greatly improved research in spray evolution. Yet, a more comprehensive understanding related to these aspects has not yet been agreed upon. Diesel spray, in particular, is considered a complicated phenomenon to observe because of its high-speed, high pressure, as well as its high temperature working condition. Nevertheless, several mechanisms have been successfully explained using fundamental studies, providing several suggestions in the area, such as liquid atomization and two-phase spray flow. There are still many aspects that have not yet been agreed upon. This paper comprehensively reviews the current status of theoretical diesel spray and modelling, including some important numerical and experimental aspects.