Effects of Equivalence Ratio on the Emission and Temperature Characteristics of Spray Flames of Jet A/Butanol Blends Under Lean Conditions

2012 ◽  
Author(s):  
Tanjir H. Ratul ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Equivalence Ratio ◽  
Flame Temperature ◽  
Nox Emission ◽  
Flame Height ◽  
Temperature Characteristics ◽  
Global Emission ◽  
Spray Flames ◽  
Index Level ◽  
Petroleum Fuels ◽  
Emission Index

Butanol is an attractive alternate fuel because it can be produced from renewable sources and has properties similar to those of petroleum fuels. Thus, blending butanol with petroleum fuels is a promising solution to reduce the dependence on petroleum fuels. In a previous study, we investigated the differences in the structure and emissions of Jet A and Butanol flames. The objective of this investigation was to study the emission and in-flame temperature characteristics of spray flames of Jet A/butanol blends at two equivalence ratios: 0.75 and 0.95. In addition to pure Jet A and pure butanol, blends of Jet A with 25%, 50% and 75% volumetric concentrations of butanol were used as fuel. The liquid fuel was atomized and combusted with air in a heated environment (479 K). The equivalence ratio was changed by altering the fuel flow rate, while maintaining the atomizing and coflow air flow rates constant, thus maintaining gas velocity field invariant. The global emission index of CO varied non-monotonically with the volume concentration of butanol in the blend at the lower equivalence ratio whereas the variation was gradual at the higher equivalence ratio. The global NOx emission index decreased monotonically as the butnaol content was increased at both equivalence ratios. The global NOx emission index level in the flames at equivalence ratio of 0.95 was higher than that at equivalence ratio of 0.75. At 25% flame height, the peak reaction zone was located off-axis; this radial location moved further away from the centerline as the equivalence ratio was increased. The peak temperatures were comparable in all the flames. The flames with butanol highlighted the effects of preferential vaporization of butanol.

Effect of Fuel Staged Proportion on NOX Emission Performance of Centrally Staged Combustor

2013 ◽  
Author(s):  
Fuqiang Liu ◽  
Yong Mu ◽  
Cunxi Liu ◽  
Jinhu Yang ◽  
Yanhui Mao ◽  
...  
Keyword(s):  
Equivalence Ratio ◽  
Flow Reactor ◽  
Flame Temperature ◽  
Plug Flow ◽  
Combustion Process ◽  
Chemical Reactor ◽  
Nox Emission ◽  
Wide Range ◽  
Pilot Fuel ◽  
Pollution Emissions

The low NOX emission technology has become an important feature of advanced aviation engine. A wide range of applications attempt to take advantage of the fact that staged combustion operating under lean-premixed-prevaporized (LPP) conditions can significantly decrease pollution emissions and improve combustion efficiency. In this paper a scheme with fuel centrally staged and multi-point injection is proposed. The mixing of fuel and air is improved, and the flame temperature is typically low in combustion zone, minimizing the formation of nitrogen oxides (NOX), especially thermal NOX. In terms of the field distribution of equivalence ratio and temperature obtained from Computational Fluid Dynamics (CFD), a chemical reactor network (CRN), including several different ideal reactor, namely perfectly stirred reactor (PSR) and plug flow reactor (PFR), is constructed to simulate the combustion process. The influences of the pilot equivalence ratio and percentage of pilot/main fuel on NOX and carbon monoxide (CO) emissions were studied by Chemical CRN model. Then the NOX emission in the staged combustor was researched experimentally. The effects of the amount of pilot fuel and primary fuel on pollution emissions were obtained by using gas analyzer. Finally, the effects of pilot fuel proportion on NOX emission were discussed in detail by comparing predicts of CRN and experimental results.

The Effect of Distance Between Fuel and Oxidizer Nozzles on NOx Emission From High Temperature Air Combustion

2011 ◽  
Author(s):  
Yuzuru Nada ◽  
Yasutomo Zenman ◽  
Takahiro Ito ◽  
Susumu Noda
Keyword(s):  
High Temperature ◽  
Flame Temperature ◽  
Dilution Effect ◽  
Nox Emission ◽  
Emission Characteristics ◽  
High Temperature Air Combustion ◽  
Flamelet Model ◽  
Scaling Parameters ◽  
Fuel Nozzle ◽  
Emission Index

This study describes NOx emission characteristics of a high temperature air combustion furnace operating with parallel jet burner system. In the parallel jet burner system, fuel nozzles are separated with a distance from an oxidizer nozzle. Objectives of this study are to clarify the effect of the distance between the fuel nozzle and the oxidizer nozzle on NOx emission. The emission index of NOx (EINOx) decreases with the increase in the distance. This is due to the dilution through entrainment of burned gas. A scaling concept is proposed to assess the dilution effect on the NOx emission. Scaling parameters employed here are the global residence time of fuel and the flame temperature evaluated on a modified flamelet model in which the dilution effect is included. The overall EINOx production rate is scaled with the flame temperature. This scaling indicates the importance of the distance between the nozzles for NOx emission.

scholarly journals Experimental study of a laminar premixed LFG/air flame in a slot burner using Mach-Zehnder interferometry

2016 ◽  
Vol 20 (5) ◽  
pp. 1649-1660 ◽  
Author(s):  
Ashrafi Najafian ◽  
Mehdi Ashjaee
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Temperature Field ◽  
Equivalence Ratio ◽  
Volume Fraction ◽  
Flame Temperature ◽  
Flame Height ◽  
Effect Of Temperature ◽  
Noticeable Effect ◽  
Present Measurement

An experimental study was conducted to investigate the influence of Reynolds number and equivalence ratio on flame temperature field and thermal flame height of laminar premixed LFG fuel. Mach-Zehnder interferometry technique is used to obtain an insight to the overall temperature field. The slot burner with large aspect ratio (L/W), length of L=60 mm and width of W=6 mm was used to eliminate the three- dimensional effect of temperature field. Two kinds of mixed fuels, LFG70 (70%CH4- 30%CO2 on volume basis) and LFG50 (50%CH4- 50%CO2) were used to investigate flame characteristics under the test conditions of 100 ? Re ? 600 and 0.7 ? ? ? 1.3. The present measurement reveals that the variation of maximum flame temperature with increment of Reynolds number is mainly due to heat transfer effects and is negligible. On the other hand, the equivalence ratio and fuel composition have a noticeable effect on flame temperature. In addition, the results show that the LFG flames compared to the CH4 ones have a lower flame temperature. With increment of CO2 volume fraction at lean combustion, thermal flame height is augmented while at stoichiometric and rich combustion, its value reduced. Thermal flame height augments linearly by Reynolds number increase, while its increment at rich mixture is higher and the effect of Reynolds number at lean mixtures is insignificant. For validation of experimental results from Mach-Zehnder Interferometry, K-type thermocouples are used at peripherally low and moderate isotherm lines.

Combustion Characteristics of Spray Flames of Canola Methyl Ester/Diesel Blends in a Furnace

2013 ◽  
Author(s):  
Cory D. Morton ◽  
Victor H. Tran ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Heat Release ◽  
Volume Fraction ◽  
Flame Temperature ◽  
Soot Volume Fraction ◽  
Combustion Characteristics ◽  
Spray Flame ◽  
Spray Flames ◽  
Refractory Bricks ◽  
Emission Index

The combustion characteristics of spray flames of canola methyl ester (CME) and blends with diesel fuel within a re-radiating environment were studied. The combustion chamber was lined with refractory bricks that were preheated to about 725 K (1305 °R). The flow rates of the fuels provided a constant heat release rate of about 7.33 kW (25,000 BTU/hr) at atmospheric pressure. Measurements of flame temperature, in-flame concentrations, global emissions, flame radiation and soot volume fraction were taken. The global CO emission index was significantly lower in the biofuel blend spray flames compared to that of the diesel spray flame. The global NO emission index was comparable for all spray flames, which agreed with peak flame temperature and in-flame NO concentration measurements. The radiative fraction of heat release was also comparable for all spray flames.

Effects of Atomization Condition on Flame Structure and Emission Characteristics of Burning Rich-Premixed Spray Jets

2007 ◽  
Author(s):  
Nobutoshi Nakachi ◽  
Masato Mikami ◽  
Naoya Kojima
Keyword(s):  
Equivalence Ratio ◽  
Droplet Diameter ◽  
Flame Structure ◽  
Flame Height ◽  
Exhaust Emission ◽  
Emission Characteristics ◽  
Combustion Modes ◽  
Atomization Condition ◽  
Emission Index ◽  
Blue Flame

Flame structure and emission characteristics of burning premixed spray were experimentally studied for different atomization conditions. Two combustion modes with and without an internal flame were observed. As Sauter mean droplet diameter became larger than a specific value, the internal flame appeared inside the external group flame. The existence of the internal flame was affected by the equivalence ratio of premixed spray jet, too. As Sauter mean droplet diameter was increased, the average flame height increased but the average blue-flame height decreased. These tendencies were same for different equivalence ratios of premixed spray jet. As the equivalence ratio of premixed spray jet was increased, the average flame height increased but the average blue-flame height did not vary very much. Exhaust emission characteristics were also affected both by Sauter mean droplet diameter and the equivalence ratio of premixed spray jet. As Sauter mean droplet diameter was increased, the emission index of CO (EICO) increased. EINO took maximum at Sauter mean droplet diameter of about 60 μm ∼ 80 μm. These tendencies in terms of Sauter mean droplet diameter were same for different equivalence ratios of premixed spray jet. EICO concentration showed low values without the internal flame.

Atomization Characteristics, Global Emissions, and Temperature in Biofuel and Petroleum Fuel Spray Flames

2008 ◽  
Author(s):  
Jaime A. Erazo ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Ambient Pressure ◽  
Flame Temperature ◽  
Combustion Products ◽  
Petroleum Fuel ◽  
Global Emission ◽  
Spray Flame ◽  
Spray Flames ◽  
Temperature Levels ◽  
Atomization Characteristics ◽  
Global Emissions

Spray flame characteristics of canola methyl ester biofuel (CME) and petroleum fuel (No. 2D) are described. An enclosed spray flame in a heated co-flow air environment at ambient pressure was studied. A single nozzle, swirl-type, air-blast atomizer with a nozzle diameter of 300 microns was used to create the spray. The spray droplet size and velocity distributions were measured using a two-component phase Doppler particle analyzer. In-flame temperature profiles were measured using a type-R thermocouple. Global emission indices of NO and CO were derived from concentration measurements in the combustion products. The overall equivalence ratio was kept at 0.75 to simulate lean burning conditions. The changes in atomization air flow rate produced similar changes in atomization characteristics of both fuels. Emission indices of NO and CO for petroleum fuel were higher than those of the CME fuel. In-flame temperature levels were lower for the CME fuel than for the petroleum fuel at corresponding flame locations.

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.

Numerical Analysis of Equivalence Ratio Fluctuations in a Partially Premixed Gas Turbine Combustor Using Large Eddy Simulations

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Ping Wang ◽  
Qian Yu ◽  
Prashant Shrotriya ◽  
Mingmin Chen
Keyword(s):  
Reaction Mechanism ◽  
Equivalence Ratio ◽  
Flame Temperature ◽  
Premixed Flames ◽  
Large Eddy Simulations ◽  
Combustion Model ◽  
Inlet Channel ◽  
Large Eddy ◽  
Partially Premixed Flames ◽  
Partially Premixed

In the present work, the fluctuations of equivalence ratio in the PRECCINSTA combustor are investigated via large eddy simulations (LES). Four isothermal flow cases with different combinations of global equivalence ratios (0.7 or 0.83) and grids (1.2 or 1.8 million cells) are simulated to study the mixing process of air with methane, which is injected into the inlet channel through small holes. It is shown that the fluctuations of equivalence ratio are very large, and their ranges are [0.4, 1.3] and [0.3, 1.2] for cases 0.83 and 0.7, respectively. For simulating turbulent partially premixed flames in this burner with the well-known dynamically thickened flame (DTF) combustion model, a suitable multistep reaction mechanism should be chosen aforehand. To do that, laminar premixed flames of 15 different equivalence ratios are calculated using three different methane/air reaction mechanisms: 2S_CH4_BFER, 2sCM2 reduced mechanisms and GRI-Mech 3.0 detailed reaction mechanism. The variations of flame temperature, flame speed and thickness of the laminar flames with the equivalence ratios are compared in detail. It is demonstrated that the applicative equivalence ratio range for the 2S_CH4_BFER mechanism is [0.5, 1.3], which is larger than that of the 2sCM2 mechanism [0.5, 1.2]. Therefore, it is recommended to use the 2S_CH4_BFER scheme to simulate the partially premixed flames in the PRECCINSTA combustion chamber.

Fuel Stratification Influence on NOx Emission in a Premixed Axial Reacting Jet-in-Crossflow at High Pressure

2021 ◽  
Vol 143 (12) ◽  
Author(s):  
Bernhard Stiehl ◽  
Tommy Genova ◽  
Michelle Otero ◽  
Scott Martin ◽  
Kareem Ahmed
Keyword(s):  
Equivalence Ratio ◽  
Vortex Pair ◽  
No Production ◽  
Nox Formation ◽  
Local Flow ◽  
Detailed Chemistry ◽  
Jet In Crossflow ◽  
Global Emission ◽  
Fuel Stratification ◽  
Jet Trajectory

Abstract Three reacting jet-in-crossflow (JiC) methane/air flames were numerically investigated in a lean axially staged combustor at a pressure of five atmospheres. A detailed chemistry Star-CCM+ computational fluid dynamics (CFD) model was used with 53 species considered and the result of turbulence-governed finite-rate modeling was validated with in-house experimental data. An optically accessible test section features three side windows, allowing local flow and flame analysis with particle image velocimetry (PIV) and CH* chemiluminescence as well as pressure, temperature, and species exit measurements. The research objective was to predict and verify NOx formation of the premixed 12.7 mm axial jet. Three headend temperature levels were investigated along with three premixed jets at lean (φJet = 0.75), near-stoichiometric (φJet = 1.07), and rich (φJet = 1.78) axial fuel line equivalence ratio. Based on the matching exit emission concentration, global emission benefits were investigated by adjustment of the fuel stratification. The perfectly premixed methane/air flames of this study were shown to ignite at the lee-side of the jet. For the elevated headend temperature level T = 1800 K, the flame extended beyond the windward jet trajectory and caused high axial NO production. For industry application, a firing temperature of 1920 K was achieved with a NOx optimized fuel split of 25%, combining a lean headend (φHeadend = 0.61) with a rich (φJet = 1.78) jet equivalence ratio. This operating point allowed minimization of the combustor residence time at temperatures above 1700 K as well as combustion in a compact flame at the jet lee-side along the counter rotating vortex pair.

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