Investigation of the Combustion Performance of a Novel Twin-fluid Fuel Injector on Different Liquid Fuels PDF Download

Author: Oladapo S. Akinyemi
Publisher:
ISBN:
Category : Atomizers
Languages : en
Pages : 360

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Author: Yonas Goitom Niguse
Publisher:
ISBN:
Category :
Languages : en
Pages : 404

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Book Description
Research on alternative fuel combustion systems is important to address global energy and environmental concerns. Renewable fuels, such as biofuels have attracted significant attention as potential sources to achieve energy security and to tackle environmental issues. However, these alternatives haven't yet been fully utilized because much of the existing combustion systems are set up for traditional fossil-fuels. This study focuses on fuel-flexible combustion of diesel, vegetable oil (VO) and glycerol fuels by a novel technique of twin-fluid atomization known as Flow Blurring (FB) atomization, at different operating pressures. The first part of this study discusses scalability considerations of FB atomization, with an objective to develop a scaled-up fuel-flexible combustor. Several scaling parameters that affect the processes of atomization, fuel-air mixing, and combustion are analyzed to select scaling criteria for all components of the combustor. A scaled-up 60-kWth capacity combustor is developed and experimentally investigated using diesel and VO fuels. Results show that the scaled-up system's performance is comparable to the small scale system in terms of flame appearance, emission levels, and static flame stability. Next, the scaled-up system's combustion performance with glycerol fuel is investigated in laboratory and at industrial test site. Glycerol is extremely difficult to atomize because of its high viscosity. The lab combustor was able to burn glycerol cleanly, with low CO and NOx emissions. At industrial test site, combustion experiments with 40% methane and 60% glycerol resulted in stable flame. Next, effect of operating pressure on flame characteristics and injector pressure drop is experimentally investigated with diesel, at pressures ranging from 101.3 kPa to 450 kPa. Normalized pressure drop across the injector increased with increase in atomizing air flow rate and decreased with increase in pressure. An increase in chamber pressure resulted in increase in CO levels and decrease in NOx emissions. Increase in pressure also produced less lifted flames with increased yellow zones. Finally, combustion performance of VO is investigated at elevated pressures. Compared to diesel, VO produced larger flames exhibiting more distributed combustion and lower NOx emissions. At high pressures diesel flames contained significantly higher portions of yellow or sooty regions compared to VO.

Author: Lulin Jiang
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 207

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Book Description
Diminishing fossil fuel resources, ever-increasing energy cost, and the mounting concerns for environmental emissions have precipitated worldwide research on alternative fuels. Biodiesel, a popular renewable energy source, is produced from the transesterification process of source oils such as vegetable oil (VO) requiring processing cost and energy input. However, highly viscous glycerol produced as the waste byproduct also decreases the economically viability of biodiesel. Previous studies show that without fuel preheating or hardware modification, high viscosity fuels such as VO and glycerol cannot be burnt cleanly with the application of the typical air blast (AB) injector due to the high viscosity. However, extremely low emissions of diesel, kerosene, biodiesel, straight VO and glycerol flames at the combustor exit are reported using a novel flow blurring (FB) injector. The PDPA measurements in the FB sprays at least 1.0 cm downstream of the injector exit quantitatively show the superior fuel-flexibility and atomization capability of the FB injector as compared to the AB atomizer. This study seeks to gain insight into the detailed flame structure of both conventional and alternative fuels atomized by the FB injector. The atomization mechanism in the FB injector near field is also investigated using a high speed imaging technique and particle image velocimetry (PIV) to explore the FB spray characteristics in the near field of the injector. First, the combustion of diesel, biodiesel and straight vegetable oil (VO) using a Flow Blurring (FB) injector is investigated. Measurements of gas temperature and CO and NOx concentrations at various axial and radial locations of the combustor are acquired using custom-designed thermocouple and gas sampling probes. Heat loss rate through the combustor is estimated from wall temperatures measured by an infra-red camera. A simple droplet model is used to predict fuel vaporization behaviour in the dark-region near the injector exit. Results show that the FB injector produced low-emission clean blue flames indicating mainly premixed combustion for all three fuels. Matching profiles of heat loss rate and product gas temperature show that the combustion efficiency is fuel independent. Next, a fuel-flexible dual-fuel combustor to simultaneously burn methane and/or straight glycerol without preheating either glycerol or air is investigated by utilizing a FB liquid fuel injector. Product gas temperature, NOX and CO emissions at multiple locations inside the combustor are measured to quantitatively assess the flame structure, related to liquid atomization, droplet evaporation, and fuel-air mixing in the near field. The impact of fuel mix and air to liquid mass ratio (ALR) on combustion performance is investigated. Pure glycerol flame is also investigated to demonstrate the fuel flexibility and ease of switching between gas and liquid fuels in the present system. Results show that the methane combustion can assist glycerol vaporization to results in its rapid oxidation. In spite of the differences in the flame structure, profiles of product gas temperature and emissions at the combustor exit reveal that complete and mainly lean premixed combustion with low emissions is achieved for all of the test cases indicating excellent fuel flexibility of the present combustor using the FB injector. Next, high-speed visualization and time-resolved Particle Image Velocimetry (PIV) techniques are employed to investigate the FB spray in the near field of the injector to delineate the underlying mechanisms of atomization. Experiments are performed using water as the liquid and air as the atomizing gas. Flow visualization at the injector exit focused on field of view with the dimension of 2.3 mm x 1.4 mm, spatial resolution of 7.16 æm per pixel, exposure time of 1 æs, and image acquisition rate of 100 k frames per second (fps). Image sequence illustrates mostly fine droplets indicating that primary breakup by FB atomization occurs within the injector. Few larger droplets appearing at the injector periphery undergo secondary breakup by Rayleigh-Taylor instabilities. Time-resolved PIV technique is applied to quantify the droplet dynamics in the injector near field. Plots of instantaneous, mean, and root-mean-square droplet velocities are presented to reveal the secondary breakup process. Results show that the secondary atomization process to produce fine and stable spray is complete within a short distance of about 5.0 mm from the injector exit. These superior characteristics of the FB injector are desirable to achieve clean combustion of different fuels in practical systems. The impact of ALR shows that the increase in ALR improves both primary FB atomization and secondary atomization in the near field. Next, glycerol atomization in the near field of the FB injector is investigated in detail. Time-resolved PIV with exposure time of 1 ms and laser pulse rate of 15 kHz is utilized to probe the glycerol spray at spatial resolution of 16.83 æm per pixel. PIV results describe the droplet dynamics in terms of the instantaneous, mean, and root-mean-square (RMS) velocities, and space-time analysis and probability distribution profiles of the axial velocity. In addition, high-speed imaging (75 kHz) coupled with backside lighting is applied to reveal the glycerol breakup process at spatial resolution of 7.16 æm per pixel and exposure time of 1 æs. Results show that the primary breakup by FB atomization or bubble explosion within the injector results in a combination of slow-moving streaks and fast-moving droplets at the injector exit. Then, the secondary breakup by Rayleigh-Taylor instability occurs at farther downstream locations where the high-velocity atomizing air stretches the streaks into thin streaks that disintegrate into smaller streaks, and subsequently, into fine droplets. Thus, within a short distance downstream of the injector exit (

Author: Md Nayer Nasim
Publisher:
ISBN:
Category : Atomizers
Languages : en
Pages : 0

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Author: Avinash Kumar Agarwal
Publisher: Springer
ISBN: 9811332754
Category : Technology & Engineering
Languages : en
Pages : 257

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Book Description
This book describes the discusses advanced fuels and combustion, emission control techniques, after-treatment systems, simulations and fault diagnostics, including discussions on different engine diagnostic techniques such as particle image velocimetry (PIV), phase Doppler interferometry (PDI), laser ignition. This volume bridges the gap between basic concepts and advanced research in internal combustion engine diagnostics, making it a useful reference for both students and researchers whose work focuses on achieving higher fuel efficiency and lowering emissions.

Author: John Ernest Stevenson
Publisher:
ISBN:
Category : Fuel
Languages : en
Pages : 54

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Book Description
A new liquid-fuel injector was designed for use in the atmospheric-pressure, model gas turbine combustor in Bucknell University's Combustion Research Laboratory during alternative fuel testing. The current liquid-fuel injector requires a higher-than-desired pressure drop and volumetric flow rate to provide proper atomization of liquid fuels. An air-blast atomizer type of fuel injector was chosen and an experiment utilizing water as the working fluid was performed on a variable-geometry prototype. Visualization of the spray pattern was achieved through photography and the pressure drop was measured as a function of the required operating parameters. Experimental correlations were used to estimate droplet sizes over flow conditions similar to that which would be experienced in the actual combustor. The results of this experiment were used to select the desired geometric parameters for the proposed final injector design and a CAD model was generated. Eventually, the new injector will be fabricated and tested to provide final validation of the design prior to use in the combustion test apparatus.

Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 1096

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Author: Wadysaw Mitianiec
Publisher: Nova Science Publishers
ISBN: 9781536124729
Category : Two-stroke cycle engines
Languages : en
Pages : 0

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Book Description
The main goal of the book is the presentation of the last theoretical and experimental works concerning fuel injection systems, mainly in small power two-stroke engines as well as in marine engines. This book includes thirteen chapters devoted to the processes of fuel injection and the combustion that takes place in a stratified charge within the cylinders of two-stroke engines. In the first two chapters, the division into different injection systems in two-stroke engines and each injection system is briefly described. Various theoretical and practical solutions of fueling system designs are described. In Chapter Three, mathematical models, the spatial movement of gas in the cylinder and the combustion chamber are introduced, taking into account the turbulence of the charge. Chapter Four relates to the behavior of fuel injected into the gaseous medium, including evaporation processes, disintegration and processes occurring while the fuel drops connect with the wall. The next section describes the zero-dimensional model of fuel injection in two-stroke engines along with examples of numerical calculations. The sixth chapter is devoted to CFD multi-dimensional models of movement and evaporation of the fuel in a closed gaseous medium, occurring also in other engine types. Chapter Seven describes a two-zone model of the combustion process and the effect of the geometry of the combustion chamber on the flame propagation with a simplified verification model of combustion. Chapter Eight compares the propagation phase of gas and liquid fuels concerning direct fuel injection as well as the direct fuel injection from the cylinder head and the thermodynamic parameters of the charge. The formation of the components during the combustion process in the direct fuel injection two-stroke engine was obtained by numerical calculations and results are discussed in Chapter Nine. Chapter Ten describes the parameters of the two-stroke engine with a direct fuel injection carried out at the Cracow University of Technology. Additionally, the chapter presents CFD simulations of fuel propagation and combustion processes, taking into account the formation of toxic components and exhaust gas emission. The processes of two direct rich mixture injection systems FAST and RMIS developed in CUT are presented in Chapter Eleven. Miscellaneous problems of direct fuel injection, such as characteristics of fuel injectors, problems of direct gaseous fuel injection, and the application of fuelling systems in outboard engines and snowmobile vehicles are presented in Chapter Twelve. A comparison of working parameters in two- and four stroke engines is also mapped out. The last chapters contain the final conclusions and remarks concerning fuel injection and emission of exhaust gases in small two-stroke engines. This book is a comprehensive monograph on fuel injection. The author presents a series of theoretical and design information from his own experience and on the basis of the works of other authors. The main text intends to direct fuel injection with respect to gas motion in the combustion chamber and influence the injection parameters for exhaust emission. The book presents its own theoretical work and experimental tests concerning a two-stroke gasoline engine with electrically controlled direct fuel injection. The book describes the processes of a general nature also occurring in other types of engines and presents a comparison of different injection systems on working parameters and gas emission. The book contains 294 images, 290 equations and 16 tables obtained from the CFD simulation and experimental works.

Author: Greg Banish
Publisher: CarTech Inc
ISBN: 1932494901
Category : Technology & Engineering
Languages : en
Pages : 130

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Book Description
Greg Banish takes his best-selling title, Engine Management: Advanced Tuning, one step further as he goes in-depth on the combustion basics of fuel injection as well as benefits and limitations of standalone. Learn useful formulas, VE equation and airflow estimation, and more. Also covered are setups and calibration, creating VE tables, creating timing maps, auxiliary output controls, start to finish calibration examples with screen shots to document the process. Useful appendixes include glossary and a special resources guide with standalone manufacturers and test equipment manufacturers

Author: Władysław Mitianiec
Publisher:
ISBN: 9781536129410
Category : Two-stroke cycle engines
Languages : en
Pages :

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