Effects of Fuel-Side N2, CO2, H2O Dilution on Combustion Characteristics and NOx Formation of Syngas Turbulent Nonpremixed Jet Flames

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Liying Zhuo ◽  
Yong Jiang ◽  
Rong Qiu ◽  
Jiangtao An ◽  
Wu Xu
Keyword(s):  
International Workshop ◽  
Flame Structure ◽  
Flame Temperature ◽  
Nonpremixed Flames ◽  
Nox Formation ◽  
Extinction Process ◽  
Turbulent Nonpremixed ◽  
Fuel Mixtures ◽  
The One ◽  
Good Agreement

The effects of the three fuel-side diluents N2, CO2, and H2O on the accurate flame structure and NOx formation characteristics of the turbulent syngas nonpremixed flames are investigated using the one-dimensional-turbulence (ODT) model. For nonpremixed flames, the fuel mixtures consist of H2, CO and three diluents: N2, H2O, and CO2. The proportion of diluents is varied from 10% to 30% while the H2/CO ratio is kept as a constant at 0.75 all the time. Mass fraction of main species and temperature of 30% N2 basic dilution case predicted by the ODT model are compared with the tests measuring results obtained by International Workshop on Measurements and Computation of Turbulent Nonpremixed Flames, and it is found that the results are in good agreement. Numerical results indicate that the CO2 diluted flames have the largest reduction on flame temperature as well as the NOx emission, while H2O is more effective than N2. For CO2 and H2O dilution flames, flame structure becomes unstable with an obvious lift phenomenon. Since ODT captures the flame extinction process, flames added with CO2 and H2O not only have a lower extinction temperature but also the reignition process is slower.

Aspect Ratio Effects on Partially Premixed Flames From Elliptic Burners in Coflow

2006 ◽  
Author(s):  
P. Hariharan ◽  
C. Periasamy ◽  
S. R. Gollahalli
Keyword(s):  
Flame Structure ◽  
Flame Temperature ◽  
Premixed Flames ◽  
Combustion Products ◽  
Jet Flame ◽  
Aspect Ratios ◽  
Partially Premixed Flames ◽  
Partially Premixed ◽  
Comparison Measurements ◽  
Good Agreement

In this paper, partially premixed flames of propane-hydrogen blends from elliptic burner geometries in coflow environment have been experimentally studied. Two different elliptic burner geometries with aspect ratios (AR) of 3:1 and 4:1 were used. A circular burner with the same discharge area as that of the elliptic burner was employed for comparison. Measurements were taken at stoichiometric and three other equivalence ratios. Global flame characteristics such as visible height, emission indices, and flame radiation were measured. Flame structure data such as transverse profiles of inflame concentrations of combustion products and local flame temperature were also measured at three axial locations in the flame. Results indicate that elliptic burner flames were shorter, more radiating, and produced lower NO and CO emissions than the corresponding circular burner flames. Results from the inflame measurements of NO and CO were in good agreement with the corresponding global data. Further, the 4:1 AR elliptic burners exhibited a twin-jet flame structure at fuel-rich conditions. The twin-flame structure was evident from the inflame measurements of temperature and combustion species. This study suggests that the combination of elliptic burner geometry and coflow reduces NO and CO emissions from combustion systems, which could potentially lead to cleaner environment.

The Effects of Fuel Mixtures in Nonpremixed Combustion for a Bluff-Body Flame

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Lu Chen ◽  
Francine Battaglia
Keyword(s):  
Bluff Body ◽  
Turbulence Models ◽  
Industrial Applications ◽  
Oh Radicals ◽  
No Production ◽  
Nonpremixed Flames ◽  
No Emission ◽  
Nonpremixed Combustion ◽  
Turbulent Nonpremixed ◽  
Fuel Mixtures

A numerical investigation is presented assessing the effects of hydrogen compositions and nonflammable diluent mixtures on the combustion and NO emission characteristics of syngas nonpremixed flames for a bluff-body burner. An assessment of turbulent nonpremixed modeling techniques is presented and is compared with the experiments of Correa and Gulati (1992, “Measurements and Modeling of a Bluff Body Stabilized Flame,” Combust. Flame, 89(2), pp. 195–213). The realizable k–ε and the Reynolds stress (RSM) turbulence models were found to perform the best. As a result, increased hydrogen content caused the radial velocity and strain rate to decrease, which was important for mixing whereby NO production decreased. Also, the effectiveness of nonflammable diluent mixtures of N2, CO2, and H2O was characterized in terms of the ability to reduce NO emission in syngas nonpremixed flames. Results indicated that CO2 was the most effective diluent to reduce NO emission and H2O was more effective than N2. CO2 produced low levels of OH radical, which made CO2 the most effective diluent. Although H2O increased OH radicals, it was still effective to reduce thermal NO because of its high specific heat. It will be numerically shown that hydrogen concentration in the H2/CO/N2 flame does not significantly affect temperature but dramatically decreases NO emission, which is important for industrial applications that can use hydrogen in syngas flames.

Reduction of NOx Formation by Water Sprays in Strained Two-Stage Flames

1997 ◽  
Vol 119 (4) ◽  
pp. 836-843 ◽  
Author(s):  
S. C. Li ◽  
N. Ilincic ◽  
F. A. Williams
Keyword(s):  
Diffusion Flames ◽  
Laser Sheet ◽  
Flame Structure ◽  
Flame Temperature ◽  
Temperature Fields ◽  
Two Stage ◽  
Two Phase ◽  
Nox Formation ◽  
Numerical Predictions ◽  
Water Sprays

Staged combustion can be employed to reduce the formation of CO and NOx, stabilize the flame, decrease the flame temperature, and create better working conditions in gas turbine combustors. To help understand influences of partial premixing and addition of water on NOx formation, we study two-stage flames in a counterflow spray burner. This paper reports experimental and theoretical results concerning two-stage combustion in which one feed stream is composed of a fuel-rich mixture of methane and air and the other is air. Water sprays are added to the air stream. This two-phase laminar counterflow configuration exhibits a green premixed flame, a blue diffusion flame, and a vaporization plane. All three are flat and parallel. The separation distances between them decrease with increasing equivalence ratio and strain rate. Flow visualization is provided through illumination by an argon ion laser sheet, velocity fields and spray structure are measured by a phase-doppler particle analyzer, concentration fields of major stable species are measured by gas chromatography of samples withdrawn from the flame, and temperature fields are measured by a thermocouple. Numerical integrations that employ a recent chemical-kinetic data base are performed to model the flame structure and NOx formation. Comparisons of experimental results with numerical predictions are made to test agreement. This work provides information on hydrocarbon combustion in both premixed flames and diffusion flames, indicates how NOx is formed in fuel-rich flames, and suggests how the pollutants can be reduced.

scholarly journals Reduction of NOx Formation by Water Sprays in Strained Two-Stage Flames

1996 ◽  
Author(s):  
S. C. Li ◽  
N. Ilincic ◽  
F. A. Williams
Keyword(s):  
Diffusion Flames ◽  
Laser Sheet ◽  
Flame Structure ◽  
Flame Temperature ◽  
Temperature Fields ◽  
Two Stage ◽  
Two Phase ◽  
Nox Formation ◽  
Numerical Predictions ◽  
Water Sprays

Staged combustion can be employed to reduce the formation of CO and NOx, stabilize the flame, decrease the flame temperature and create better working conditions in gas turbine combustors. To help understand influences of partial premixing and addition of water on NOx formation, we study two-stage flames in a counterflow spray burner. This paper reports experimental and theoretical results concerning two-stage combustion in which one feed stream is composed of a fuel-rich mixture of methane and air and the other is air. Water sprays are added to the air stream. This two-phase laminar counterflow configuration exhibits a green premixed flame, a blue diffusion flame and a vaporization plane. All three are flat and parallel. The separation distances between them decrease with increasing equivalence ratio and strain rate. Flow visualization is provided through illumination by an argon ion laser sheet, velocity fields and spray structure are measured by a phase-doppler particle analyzer, concentration fields of major stable species are measured by gas chromatography of samples withdrawn from the flame, and temperature fields are measured by a thermocouple. Numerical integrations which employ a recent chemical-kinetic data base are performed to model the flame structure and NOx formation. Comparisons of experimental results with numerical predictions are made to test agreement. This work provides information on hydrocarbon combustion in both premixed flames and diffusion flames, indicates how NOx is formed in fuel-rich flames and suggests how the pollutants can be reduced.

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

scholarly journals Estimation of the Noise Source Level of a Commercial Ship Using On-Board Pressure Sensors

2021 ◽  
Vol 11 (3) ◽  
pp. 1243
Author(s):  
Hongseok Jeong ◽  
Jeung-Hoon Lee ◽  
Yong-Hyun Kim ◽  
Hanshin Seol
Keyword(s):  
Noise Source ◽  
Pressure Sensors ◽  
Low Frequency ◽  
Frequency Resolution ◽  
Source Strength ◽  
Recording Time ◽  
Source Level ◽  
The One ◽  
Hydrophone Array ◽  
Good Agreement

The dominant underwater noise source of a ship is known to be propeller cavitation. Recently, attempts have been made to quantify the source strength using on-board pressure sensors near the propeller, as this has advantages over conventional noise measurement. In this study, a beamforming method was used to estimate the source strength of a cavitating propeller. The method was validated against a model-scale measurement in a cavitation tunnel, which showed good agreement between the measured and estimated source levels. The method was also applied to a full-scale measurement, in which the source level was measured using an external hydrophone array. The estimated source level using the hull pressure sensors showed good agreement with the measured one above 400 Hz, which shows potential for noise monitoring using on-board sensors. A parametric study was carried out to check the practicality of the method. From the results, it was shown that a sufficient recording time is required to obtain a consistent level at high frequencies. Changing the frequency resolution had little effect on the result, as long as enough data were provided for the one-third octave band conversion. The number of sensors affected the mid- to low-frequency data.

Study on the Effect of Adiabatic Flame Temperature on NOx Formation Using Ethanol Gasoline Blend in SI Engine

2013 ◽  
Vol 781-784 ◽  
pp. 2471-2475 ◽  
Author(s):  
B. M. Masum ◽  
M.A. Kalam ◽  
H.H. Masjuki ◽  
S. M. Palash
Keyword(s):  
Equivalence Ratio ◽  
Gasoline Engine ◽  
Flame Temperature ◽  
Inlet Temperature ◽  
Si Engine ◽  
Nox Formation ◽  
Adiabatic Flame Temperature ◽  
No Formation ◽  
Blended Fuel ◽  
Active Research

Active research and development on using ethanol fuel in gasoline engine had been done for few decades since ethanol served as a potential of infinite fuel supply. This paper discussed analytically and provides data on the effects of compression ratio, equivalence ratio, inlet temperature, inlet pressure and ethanol blend in cylinder adiabatic flame temperature (AFT) and nitrogen oxide (NO) formation of a gasoline engine. Olikara and Borman routines were used to calculate the equilibrium products of combustion for ethanol gasoline blended fuel. The equilibrium values of each species were used to predict AFT and the NO formation of combustion chamber. The result shows that both adiabatic flame temperature and NO formation are lower for ethanol-gasoline blend than gasoline fuel.

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