Experimental Study of Nanoadditives for Biofuel Combustion Improvement

2011 ◽  
Author(s):  
Calvin Hong Li
Keyword(s):  
Element Composition ◽  
Heat Of Combustion ◽  
Combustion Model ◽  
Volume Fractions ◽  
Ethanol Combustion ◽  
Al2o3 Particles ◽  
Static Bomb ◽  
Heat Released ◽  
System Combustion ◽  
Good Agreement

An experimental investigation of the combustion behavior of nano-aluminum (n-Al) and nano-aluminum oxide (n-Al2O3) particles, stably suspended in biofuel (ethanol) as a secondary energy carrier was conducted. The heat of combustion (HoC) was studied using a modified static bomb calorimeter system. Combustion element composition and surface morphology were evaluated using a SEM/EDS system. N-Al and n-Al2O3 particles of 50 nm and 36 nm diameters, respectively, were utilized in this investigation. Combustion experiments were performed with volume fractions of 1%, 3%, 5%, 7%, and 10% for n-Al, and 0.5%, 1%, 3%, and 5% for n-Al2O3. The results indicate that the amount of heat released from ethanol combustion increases almost linearly with n-Al concentration. N-Al volume fractions of 1% and 3% did not show enhancement in the average volumetric heat of combustion, but higher volume fractions of 5%, 7%, and 10% increased the volumetric heat of combustion by 5.82%, 8.65%, and 15.31%, respectively. N-Al2O3 and heavily passivated n-Al additives did not participate in combustion reactively, and there was no contribution from Al2O3 to the HoC in the tests. A combustion model that utilized Chemical Equilibrium with Applications (CEA) was conducted as well and was shown to be in good agreement with the experimental results.

scholarly journals SENSITIVE ANALYSIS OF A COAL COMBUSTION MODEL ON A DROP TUBE FURNACE

2013 ◽  
Vol 12 (2) ◽  
pp. 51
Author(s):  
L. Zimmer ◽  
F. M. Pereira ◽  
P. S. Schneider
Keyword(s):  
Coal Combustion ◽  
Reference Model ◽  
Sensitivity Study ◽  
Tube Furnace ◽  
Combustion Model ◽  
Drop Tube ◽  
Drop Tube Furnace ◽  
Flow Heat ◽  
Working Parameters ◽  
Good Agreement

In the present work a one-dimensional model for coal combustion in a Drop Tube Furnace (DTF) is developed. The equations that characterize the flow, heat transfer phenomena and coal combustion reactions are programmed in a FORTRAN90 language code. The results are compared with a reference model and experimental data, showing good agreement. A sensitivity study is performed to understand the behavior of coal combustion due to changes of some working parameters of the DTF. From the variation of the oxygen concentration, working temperature and input flow rates the response of the coal combustion in terms of unburned fraction can be obtained.

Application of Various Combustion Models to a Generic Combustor

2003 ◽  
Author(s):  
Lei-Yong Jiang ◽  
Ian Campbell
Keyword(s):  
Experimental Tests ◽  
Combustion Model ◽  
Discrete Ordinates ◽  
Experimental Measurements ◽  
Finite Rate ◽  
Zone Length ◽  
Combustion Models ◽  
The Mean ◽  
Heat Transfers ◽  
Good Agreement

The flow-field of a generic gas combustor with interior and exterior conjugate heat transfers was numerically studied. Results obtained from three combustion models, combined with the re-normalization group (RNG) k-ε turbulence model, discrete ordinates radiation model, and partial equilibrium NOx model are presented and discussed. The numerical results are compared with a comprehensive database obtained from a series of experimental tests. The flow patterns and the recirculation zone length are excellently predicted, and the mean axial velocities are in fairly good agreement with the experimental measurements, particularly at downstream sections for all three combustion models. The mean temperature profiles are also fairly well captured by the probability density function (PDF) and eddy dissipation (EDS) combustion models. The EDS-finite-rate combustion model fails to provide acceptable temperature field. In general, the PDF shows some superiority over the EDS and EDS-finite-rate models. NOx levels predicted by the EDS model are in reasonable agreement with the experimental measurements.

scholarly journals Understanding the diesel-like spray characteristics applying a flamelet-based combustion model and detailed large eddy simulations

2019 ◽  
Vol 21 (1) ◽  
pp. 134-150 ◽  
Author(s):  
Eduardo J Pérez-Sánchez ◽  
Jose M Garcia-Oliver ◽  
Ricardo Novella ◽  
Jose M Pastor
Keyword(s):  
Flame Stabilization ◽  
Large Eddy Simulations ◽  
Combustion Model ◽  
Progress Variable ◽  
Auto Ignition ◽  
Large Eddy ◽  
Engine Combustion ◽  
Spatial Fields ◽  
Lift Off ◽  
Good Agreement

This investigation analyses the structure of spray A from engine combustion network (ECN), which is representative of diesel-like sprays, by means of large eddy simulations and an unsteady flamelet progress variable combustion model. A very good agreement between modelled and experimental measurements is obtained for the inert spray that supports further analysis. A parametric variation in oxygen concentration is carried out in order to describe the structure of the flame and how it is modified when mixture reactivity is changed. The most relevant trends for the flame metrics, ignition delay and lift-off length are well-captured by the simulations corroborating the suitability of the model for this type of configuration. Results show that the morphology of the flame is strongly affected by the boundary conditions in terms of the reactive scalar spatial fields and Z–T maps. The filtered instantaneous fields provided by the simulations allow investigation of the structure of the flame at the lift-off length, whose positioning shows low fluctuations, and how it is affected by turbulence. It is evidenced that small ignition kernels appear upstream and detached from the flame that eventually merge with its base in agreement with experimental observations, leading to state that auto-ignition plays a key role as one of the flame stabilization mechanisms of the flame.

Performance and Emission Predictions for a Multi-Cylinder Spark Ignition Engine

1977 ◽  
Vol 191 (1) ◽  
pp. 339-354 ◽  
Author(s):  
R. S. Benson ◽  
P. C. Baruah
Keyword(s):  
Wave Equations ◽  
Spark Ignition ◽  
Reaction Scheme ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Performance And Emission ◽  
Nitric Oxide Formation ◽  
Performance And Emissions ◽  
The Common ◽  
Good Agreement

A comparison is made of experimental results and predictions of performance and emissions from a multi-cylinder spark ignition engine over a range of air-fuel ratios and two throttle settings. The results showed that a simplified two zone combustion model, a seven reaction scheme for nitric oxide formation, a partial freezing model for carbon monoxide and the inclusion of chemical reactions and variable specific heat along the pathlines in the wave equations gave good agreement with the measurements at the common pipe junction and exhaust outlet, but due to cyclic dispersion and maldistribution of fuel between cylinders the predictions of the emissions in the exhaust manifold adjacent to the cylinder were not so good. The predicted air flow and indicated power agreed well with experiment.

scholarly journals Prediction of a Small-Scale Pool Fire with FireFoam

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Camilo Andrés Sedano ◽  
Omar Darío López ◽  
Alexander Ladino ◽  
Felipe Muñoz
Keyword(s):  
Numerical Results ◽  
Pool Fire ◽  
Flame Height ◽  
Combustion Model ◽  
Small Scale ◽  
Average Temperature ◽  
Eddy Simulation ◽  
Fire Experiment ◽  
Large Eddy ◽  
Good Agreement

A computational model using Large Eddy Simulation (LES) for turbulence modelling was implemented, by means of the Eddy Dissipation Concept (EDC) combustion model using the fireFoam solver. A small methanol pool fire experiment was simulated in order to validate and compare the numerical results, hence trying to validate the effectiveness of the solver. A detailed convergence analysis is performed showing that a mesh of approximately two million elements is sufficient to achieve satisfactory numerical results (including chemical kinetics). A good agreement was achieved with some of the experimental and previous computational results, especially in the prediction of the flame height and the average temperature contours.

Nitric Oxide Formation in Diesel Engines

1974 ◽  
Vol 188 (1) ◽  
pp. 477-483 ◽  
Author(s):  
H. Çakir
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Analytical Solutions ◽  
Diesel Engines ◽  
Operating Conditions ◽  
Experimental Results ◽  
Combustion Model ◽  
Oxide Formation ◽  
Nitric Oxide Formation ◽  
Good Agreement

A combustion model is presented to account for the nitric oxide formation in diesel engines at all operating conditions. The paper tries to introduce the concept of variable air-fuel ratio estimated to exist during diesel combustion. Analytical solutions are found to be in good agreement with experimental results. Further investigations will be directed to diesel engines having combustion systems other than the M.A.N.-FM system, and to possible remedies to reduce the formation of nitrogen oxides.

scholarly journals COMBUSTION MODEL FOR SPARK IGNITION ENGINES OPERATING ON GASOLINE-ETHANOL BLENDS

2010 ◽  
Vol 9 (1-2) ◽  
pp. 89
Author(s):  
J. M. Mantilla ◽  
D. A. Garzón ◽  
C. H. Galeano
Keyword(s):  
Original Work ◽  
Turbulent Flame ◽  
Combustion Efficiency ◽  
Combustion Model ◽  
Spark Ignition Engines ◽  
Intake Valve ◽  
Propagation Theory ◽  
Spark Timing ◽  
Ethanol Blends ◽  
Good Agreement

This article presents a phenomenological combustion model using turbulent flame propagation theory developed by Keck and coworkers, 1974. The model was adapted to work with gasoline-ethanol blends, following correlations presented by Bayraktar,2005. New sub-models were introduced for intake valve velocity and combustion efficiency. These allow simulating the effect of compression ratio, spark timing and fuel change. Results show good agreement with the ones in the original work as well as with experimental results in a Cooperative Fuels Research (CFR) engine.

scholarly journals Theoretical Analysis of the Mechanism of the 1,3-Dipolar Cycloaddition of Benzodiazepine with N-Aryl-C-ethoxycarbonylnitrilimine

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Khadija Nabih ◽  
Mohamed Maatallah ◽  
Abdesselam Baouid ◽  
Abdellah Jarid
Keyword(s):  
Energy Barrier ◽  
Addition Reaction ◽  
Cycloaddition Reaction ◽  
Reaction Medium ◽  
Dft Method ◽  
High Energy ◽  
Dipolar Cycloaddition ◽  
Concerted Mechanism ◽  
Heat Released ◽  
Good Agreement

In this work, the mechanism and regio- and no-periselectivity of the 1,3-dipolar cycloaddition reaction of 2,4-dimethyl-3H-1,5-benzodiazepine with N-aryl-C-ethoxycarbonylnitrilimine have been studied using the DFT method at the B3LYP/6-31G(d) level of theory. IRC calculations and activation energies show that this reaction follows an asynchronous concerted mechanism. The two C=N sites of 2,4-dimethyl-3H-1,5-benzodiazepine are easily reached by the dipole, and the energy barrier between the reagents and the transition states is too weak. The secondary barriers are traversed by the heat released in the reaction medium after the crossing of the first TS, which facilitates the addition reaction and does not require high energy. The obtained results of this study are in good agreement with experimental outcomes.

Study of Combustion Instabilities Imposed by Inlet Velocity Disturbance in Combustor Using LES

2009 ◽  
Author(s):  
Kenji Sato ◽  
Ed Knudsen ◽  
Heinz Pitsch
Keyword(s):  
Transfer Function ◽  
Flow Field ◽  
Heat Release ◽  
Combustion Chamber ◽  
Combustion Process ◽  
Variable Density ◽  
Combustion Model ◽  
Combustion Instabilities ◽  
Inlet Velocity ◽  
Good Agreement

Stable combustion is one of the most important requirements for the development of heavy duty gas turbine engines that comply with stringent environmental regulations at high firing temperatures. In this research, one of the typical combustion instabilities which is caused by an acoustically forced velocity disturbance is investigated using variable density LES simulations. The G-equation approach for LES is used as the combustion model [1], and an experiment by Balachandran et al. [2, 3] is selected for case study. The velocity profiles in the experimental combustion chamber are compared with experimentally measured data at non-reacting conditions and it is confirmed that these are in good agreement. At the reacting conditions, predicted flame shapes are compared with OH PLIF measurements. The transfer function of the heat release due to inlet velocity forcing at 40 Hz and 160 Hz frequencies is also compared with the experimental data. These are in good agreement, including the nonlinear response of heat release. The transfer function is highly related to the flow field. The non-linearity of the transfer function can be traced to the interaction of the flow field in the combustion chamber with the combustion process itself.

scholarly journals Combustion of a frozen bi-dispersed aluminum-water suspension

2018 ◽  
Vol 243 ◽  
pp. 00023 ◽  
Author(s):  
Vasiliy Poryazov ◽  
Aleksey Krainov
Keyword(s):  
Experimental Data ◽  
Water Vapor ◽  
Scientific Literature ◽  
Combustion Products ◽  
Combustion Model ◽  
Mass Ratio ◽  
Aluminum Particles ◽  
Water Suspension ◽  
Dispersed Aluminum ◽  
Good Agreement

This paper presents a combustion model of nano- and microsized aluminum mixture frozen in water. The model takes into account combustion of aluminum particles in water vapor, the motion of combustion products, the temperature and velocity differences between particles and gas. The obtained results of the combustion rate depending on pressure and mass ratio between dispersed Al powders are in good agreement with the experimental data described in scientific literature.

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