Fuel Stream Modeling in Flowing Section of Sprayers of Diesel Nozzles

In this study, a co-flow methane/air diffusion flame at Reynolds number of 6000 was numerically simulated. The co-flow air and fuel streams were diluted with Nitrogen in the range of 0% to 20%. The thermal and composition fields in the far-burner reaction zone (close to the exhaust) were computed, and the effects of diluent’s addition to the air stream (simulating FGR) and to the fuel stream (simulating FIR) were investigated. The results show that air-side dilution is very effective up to 5% diluent’s addition. For which, 95% and 65% drops in NO and CO emissions, respectively, along with a 16% increase in temperature, are predicted compared to the baseline case (0% dilution). However, beyond 5% dilution, no effect (reaction) has been predicted. On the other hand, the fuel-side dilution has shown an effect for all simulated diluent’s addition (i.e. 0%–20%). However, that effect is not systematic neither on temperature, CO or NO concentrations. For a similar 5% dilution to the fuel-side, a 14% increase in NO and a 97% decrease in CO are predicted, along with a 5.6% increase in temperature. The simulated results revealed that air-side dilution (simulating FGR) has a dramatic greater effectiveness in NO reduction, whereas, fuel-side dilution (simulating FIR) has a greater effectiveness in CO reduction. Besides, the results suggest an important role for Prompt-NO Fenimore mechanism.

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Effects of Operating Conditions on the Heat Management of a Microscale Fuel Cell

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2019-3903 ◽

2019 ◽

Author(s):

Liyong Sun ◽

Adam S. Hollinger ◽

Jun Zhou

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Waste Heat ◽

Heat Removal ◽

Current Collector ◽

Ambient Air ◽

Operating Conditions ◽

Heat Management ◽

Fuel Flow ◽

Fuel Stream

Abstract Higher energy densities and the potential for nearly instantaneous recharging make microscale fuel cells very attractive as power sources for portable technology in comparison with standard battery technology. Heat management is very important to the microscale fuel cells because of the generation of waste heat. Waste heat generated in polymer electrolyte membrane fuel cells includes oxygen reduction reaction in the cathode catalyst, hydrogen oxidation reaction in the anode catalyst, and Ohmic heating in the membrane. A novel microscale fuel cell design is presented here that utilizes a half-membrane electrode assembly. An ANSYS Fluent model is presented to investigate the effects of operating conditions on the heat management of this microscale fuel cell. Five inlet fuel temperatures are 22°C, 40°C, 50°C, 60°C, and 70°C. Two fuel flow rate are 0.3 mL/min and 2 mL/min. The fuel cell is simulated under natural convection and forced convection. The simulations predict thermal profiles throughout this microscale fuel cell design. The exit temperature of fuel stream, oxygen stream and nitrogen stream are obtained to determine the rate of heat removal. Simulation results show that the fuel stream dominates heat removal at room temperature. As inlet fuel temperature increases, the majority of heat removal occurs via convection with the ambient air by the exposed current collector surfaces. The top and bottom current collector removes almost the same amount of heat. The model also shows that the heat transfer through the oxygen channel and nitrogen channel is minimal over the range of inlet fuel temperatures. Increasing fuel flow rate and ambient air flow both increase the heat removal by the exposed current collector surfaces. Ultimately, these simulations can be used to determine design points for best performance and durability in a single-channel microscale fuel cell.

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Model Issues Regarding Modification of Fuel Injector Components to Improve the Injection Parameters of a Modern Compression Ignition Engine Powered by Biofuel

Applied Sciences ◽

10.3390/app9245479 ◽

2019 ◽

Vol 9 (24) ◽

pp. 5479 ◽

Cited By ~ 3

Author(s):

Jacek Eliasz ◽

Tomasz Osipowicz ◽

Karol Franciszek Abramek ◽

Łukasz Mozga

Keyword(s):

Combustion Process ◽

Quality Parameters ◽

Combustible Mixture ◽

Opening Angle ◽

Fuel Injector ◽

Compression Ignition Engine ◽

Injection Dose ◽

Innovative Idea ◽

Flow Turbulence ◽

Fuel Stream

This article presents a theoretical analysis of the use of spiral-elliptical ducts in the atomizer of a modern fuel injector. The parameters of the injected fuel stream can be divided into quantitative and qualitative. The quantitative parameter is the injection dose amount, and the qualitative parameter is characterized by the stream of injected fuel (width, atomization, opening angle, and range). The purpose of atomizer modification is to cause additional flow turbulence, which may affect the stream parameters and improve the combustion process of the combustible mixture in a diesel engine. The spiral-elliptical ducts discussed here could be used in engines powered by vegetable fuels. The stream of such fuels has worse quality parameters than conventional fuels, due to their higher viscosity and density. The proposal to use spiral-elliptical ducts is an innovative idea for diesel engines.

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The Aerodynamic Approach to Furnace Design

Journal of Engineering for Power ◽

10.1115/1.4008074 ◽

1959 ◽

Vol 81 (4) ◽

pp. 361-369 ◽

Cited By ~ 1

Author(s):

J. H. Chesters

Keyword(s):

Open Hearth ◽

Open Hearth Furnace ◽

Hearth Furnace ◽

Low Velocity ◽

Droplet Dynamics ◽

Free Jets ◽

Free Jet ◽

Side Walls ◽

Air Streams ◽

Fuel Stream

Flow patterns and mixing in actual furnaces can be best appreciated by starting with free jets and proceeding via jets in simple envelopes to jets (cold or alight) fed with surrounding air streams and impacting on surfaces. The fuel stream in an open-hearth furnace behaves initially as a free jet, entraining the relatively low velocity air around it, but on hitting the bath it splashes and runs forward and up the side walls. The gases reaching the roof eject flux droplets and then divide, part recirculating to meet the oncoming air and part joining the main flow to the exit. Future progress requires more knowledge of droplet dynamics, and demands more symmetrical flow, control of recirculation, or radical changes.

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The temperature distribution along a radiating gas stream in which heat is being liberated by a chemical reaction

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1951.0157 ◽

1951 ◽

Vol 208 (1093) ◽

pp. 247-262

Keyword(s):

Heat Transfer ◽

Heat Capacity ◽

Heat Sink ◽

Flame Temperature ◽

Convection Heat Transfer ◽

Combustion Products ◽

Distance Curve ◽

Fuel Jet ◽

Initial Fuel ◽

Fuel Stream

As a first approximation, to calculate the variation of flame temperature ( Y ) with distance ( X ) along a slowly burning flame, the flame is taken to consist of a central stream or jet of fuel which enters at the temperature ( T ) of the heat sink and entrains combustion air at a rate constant with respect to X . This entrained air is assumed to react rapidly with the fuel stream and the products of the reactions remain in the fuel stream, so that the temperature ( Y ) of the latter rises at a rate dY/dX which falls off as the heat capacity of this stream increases. When there is no heat loss from the fuel jet the temperature-distance curve is shown to be a rectangular hyperbola. The curvature at any point of the hyperbola increases as ( q ), the ratio of the heat capacity of the initial fuel stream to that of the final combustion products, decreases. In other cases heat transfer is supposed to take place by convection (α [ Y ─ T ]) orradiation (α [ Y 4 ─ T 4 ]) between the fuel jet and the heat sink with a heat-transfer coefficient which is assumed to be constant for a cylindrical flame and proportional to distance from the inlet for a conical flame. It is shown that in the case of the cylindrical flame the flame temperature must increase monotonically until combustion is complete, whereas the temperature in the conical flame can begin to fall off at an earlier stage. In the case of convection-heat transfer the shape of the temperature-distance curve is dependent only on ( q ) and on the ratio L/L 0 (where L ═ length for all combustion air to be entrained and L 0 ═ length in which all the combustion energy would be transferred to the surroundings if the flame remained at the adiabatic combustion temperature T a ). With radiative heat transfer the shape of the curves depends on ( q ) and L/L 0 but also on the ratio T/T a .

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CHANGES IN THE AREA BRIGHTNESS OF DIESEL FUEL SPRAY ZONES

Alternative energy sources in the transport-technological complex problems and prospects of rational use of ◽

10.12737/17911 ◽

2016 ◽

Vol 3 (1) ◽

pp. 506-509

Author(s):

Кулманаков ◽

S. Kulmanakov ◽

Кирюшин ◽

I. Kiryushin

Keyword(s):

Diesel Fuel ◽

Liquid Fuel ◽

Pressure Range ◽

Injection Pressure ◽

Fuel Spray ◽

Experimental Setup ◽

Jet Injection ◽

Axial Section ◽

Fuel Jet ◽

Fuel Stream

The article contains a description of the experimental setup and the stent-speed video atomized fuel stream, applicable for the study of the jet sputtering process liquid fuel. In axial section shows information about the dynamics of the area of the normalized luminance zones in the diesel fuel jet injection pressure range of 60 MPa to 180 MPa

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Running On Air

Mechanical Engineering ◽

10.1115/1.2004-jan-4 ◽

2004 ◽

Vol 126 (01) ◽

pp. 40-42

Author(s):

Kosanovic Lisa

Keyword(s):

Fuel Cell ◽

Human Body ◽

Proton Exchange Membrane ◽

Electrochemical Reaction ◽

Proton Exchange ◽

Brute Force ◽

Brute Force Method ◽

Exchange Membrane ◽

Fuel Stream ◽

Fuel Cell Operation

This article highlights that although much attention has been paid to fuel stream cleanliness, there has been little focus on the cleanliness of intake air, which is critical to proton exchange membrane (PEM) fuel cell operation in two ways. First, air supplies the oxygen needed to complete the electrochemical reaction that produces electricity. Second, air carries water, a byproduct of the process, out of the fuel cell. Otherwise, water would flood the cell and prevent oxygen from doing its part. Los Alamos scientist Francisco Uribe believes that proton exchange membrane fuel cells are much more elegant than combustors, because they operate the way nature operates. Burning is an inefficient, brute-force method of extracting energy from fuel, but using electrochemical reactions to draw chemical energy out of the fuel is similar to what the human body does to get energy. Moreover, like the human body, a PEM cell can recover if it is exposed to fresh air after poisoning from certain contaminants, such as carbon monoxide.

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Dilution and Suppression of Partially Premixed Flames in Normal and Microgravity for Different Fuels

Heat Transfer, Volume 2 ◽

10.1115/imece2006-14641 ◽

2006 ◽

Author(s):

Andrew J. Lock ◽

Alejandro Briones ◽

Suresh K. Aggarwal ◽

Ishwar K. Puri ◽

Uday G. Hegde

Keyword(s):

Volume Fraction ◽

Premixed Flames ◽

Dilution Effect ◽

Critical Volume ◽

Area Of Interest ◽

Air Stream ◽

Partially Premixed Flames ◽

Critical Volume Fraction ◽

Partially Premixed ◽

Fuel Stream

The suppression of fires and flames is an important area of interest for both terrestrial and space based applications. In this investigation we elucidate the relative efficacy of fuel and air stream inert diluents for suppressing laminar partially premixed flames. A comparison of the effects of fuel and air stream dilution are also made with other fuels. Both counterflow and coflow flames are investigated, with both normal and zerogravity conditions considered for coflow flames. Simulations are conducted for both the counterflow and coflow flames, while experimental observations are made on the coflowing flames. With fuel or air stream dilution, coflow flames are observed to move downstream from the burner after overcoming initial heat transfer coupling. Further increases in diluent result in increases in the flame liftoff height until blow off occurs. The flame liftoff height and the critical volume fraction of extinguishing agent at blow out vary with both equivalence ratio and with the stream in which diluents are introduced. Nonpremixed methane-air flames are more difficult to extinguish than partially premixed flames with fuel stream dilution; whereas, partially premixed methane-air flames are more resistant to extinction than nonpremixed flames with air stream dilution. This difference in efficacy of the fuel and air stream dilution is attributed to the action of the diluent. In leaner partially premixed flames with fuel stream dilution and richer partially premixed flames with air stream dilution the effect of the diluent is to replace the deficient reactant in the system, thus starving the flame. In leaner partially premixed flames with air stream dilution and richer partially premixed flames with fuel stream dilution the effect of the diluent is purely thermal in that it absorbs heat from the flame, until combustion may no longer be sustained. The dilution effect is more effective than the thermal effect. When gravity is eliminated from the 2-D flame the liftoff height decreases and the critical volume fraction of diluent for blow off is also decreased.

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