scholarly journals Effects of Turbulence on the Combustion Properties of Partially Premixed Flames of Canola Methyl Ester and Diesel Blends

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
N. Dhamale ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Reynolds Number ◽  
Methyl Ester ◽  
Alternative Energy ◽  
Volume Fraction ◽  
Energy Resource ◽  
Soot Volume Fraction ◽  
Air Entrainment ◽  
Combustion Properties ◽  
Partially Premixed ◽  
Emission Index

Canola methyl ester (CME) is a biofuel that is a renewable alternative energy resource and is produced by the transesterification of canola oil. The objective of this study was to document the effects of turbulence on the combustion characteristics of blends of CME and No 2 diesel fuel in a partially-premixed flame environment. The experiments were conducted with mixtures of pre-vaporized fuel and air at an initial equivalence ratio of 7 and three burner exit Reynolds numbers, 2700, 3600, and 4500. Three blends with 25, 50, and 75% volume concentration of CME were studied. The soot volume fraction was highest for the pure diesel flames and did not change significantly with Reynolds number due to the mutually compensating effects of increased carbon input rate and increased air entrainment as the Reynolds number was increased. The global NOx emission index was highest and the CO emission index was the lowest for the pure CME flame, and varied non-monotonically with biofuel content in the blend The mean temperature and the NOx concentration at three-quarter flame height were generally correlated, indicating that the thermal mechanism of NOx formation was dominant in the turbulent biofuel flames also.

Combustion Properties of Partially-Premixed Turbulent Flames of Soy Methyl Ester and Diesel Blends

2010 ◽  
Author(s):  
Nikhil S. Dhamale ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Reynolds Number ◽  
Methyl Ester ◽  
Alternative Energy ◽  
Turbulent Flame ◽  
Energy Resource ◽  
Turbulent Flames ◽  
Flame Height ◽  
Combustion Properties ◽  
Partially Premixed ◽  
Soy Methyl Ester

Soy methyl ester (SME) is a biofuel that is a renewable alternative energy resource and is produced by the transesterification of soy oil; it is carbon-neutral and low in sulphur content. The objective of this study was to document the combustion characteristics of blends of SME and No 2 diesel fuel in a partially-premixed turbulent flame environment. The experiments were conducted at an initial equivalence ratio of 7 and three Reynolds numbers (based on the injector diameter and the bulk burner-exit velocity of the air/fuel mixture): 2700, 3600 and 4500. Three blends, B25, B50 and B75 corresponding to 25, 50 and 75% volume concentration of SME were studied. The liquid fuel was completely vaporized and mixed with air before exiting the burner. The radiative heat fraction measured in the SME flames was lower than the corresponding value in pure diesel flames and increased with Reynolds number. The global emission measurements indicated that the NOx emissions from the SME-diesel blend flames were lower than those from the pure diesel flame. At quarter and half flame height the temperature peaked at the edge of the flame where as for three quarters the temperature peaked at the centerline of the flame. In-flame NOx concentrations decreased with an increase in Reynolds number. The CO emission index decreased with the increase in the SME concentration in the fuel blend and decreased with the increase in Reynolds number.

Laminar Flame Characteristics of Partially Premixed Palm Methyl Ester Gas Flames

2013 ◽  
Author(s):  
Diego Romero ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Volume Fraction ◽  
Laminar Flame ◽  
Soot Volume Fraction ◽  
Fuel Flow ◽  
Combustion Properties ◽  
Emission Index ◽  
Palm Methyl Ester

Palm methyl ester (PME) is a renewable biofuel that is produced by the transesterification of palm oil; it is a popular alternative fuel used in the transportation sector. The objective of this investigation was to study the combustion characteristics of flames of pre-vaporized diesel and PME in a laminar flame environment at initial equivalence ratios of 2, 3 and 7 and to isolate the factors attributable to chemical structure of the fuel. The equivalence ratio was changed by altering the fuel flow rate, while maintaining the air flow rate constant. The global CO emission index of the PME flames was significantly lower than that of the diesel flames; however, the global NO emission index was comparable. The radiative fraction of heat release and the soot volume fraction were lower for the PME flames compared to the diesel flames. The peak temperatures were comparable at an equivalence ratio of 2, but at higher equivalence ratios, the peak temperatures in the PME flames were higher. The measurements highlight the differences in the combustion properties of biofuels and petroleum fuels and the coupling effects of equivalence ratio.

Laminar Partially Premixed Flames of Blends of Pre-Vaporized Jet-A Fuel and Palm Methyl Ester

2014 ◽  
Author(s):  
Arun Balakrishnan ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Flow Rate ◽  
Volume Fraction ◽  
Air Flow ◽  
Soot Volume Fraction ◽  
Flame Length ◽  
Phase Reaction ◽  
Combustion Properties ◽  
Partially Premixed ◽  
Palm Methyl Ester

Biofuels, such as palm methyl ester (PME), are attractive alternates to petroleum fuels. In order to isolate the effects of fuel chemistry on the combustion properties, laminar partially premixed pre-vaporized flames of blends of Jet-A and PME (volume concentrations of 25%, 50%, 75% PME) were studied. A stainless steel circular tube (ID of 9.5 mm) served as the burner. The liquid fuel was supplied with a syringe pump into a high temperature (390°C) air flow to vaporize it completely without coking. The fuel flow rate was maintained constant and the air flow rate adjusted to obtain burner-exit equivalence ratios of 2, 3 and 7. The global flame properties including flame length, CO and NO emission indices, radiative heat fraction and in-flame properties including gas concentration (CO, CO2, NO, O2), temperature and soot volume fraction were measured. The near-burner homogeneous gas-phase reaction zone increased in length with the addition of PME at all equivalence ratios. The concentration and global emission measurements highlight the non-monotonic variation of properties with the volume concentration of PME in the fuel. The fuel-bound oxygen of PME affected the combustion properties significantly.

Laminar Flame Characteristics of Partially Premixed Prevaporized Palm Methyl Ester and Diesel Flames

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
D. Romero ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Volume Fraction ◽  
Laminar Flame ◽  
Soot Volume Fraction ◽  
Fuel Flow ◽  
Combustion Properties ◽  
Emission Index ◽  
Palm Methyl Ester

Palm methyl ester (PME) is a renewable biofuel that is produced by the transesterification of palm oil and is a popular alternative fuel used in the transportation sector, particularly in Asia. The objective of this investigation was to study the combustion characteristics of flames of prevaporized number 2 diesel and PME in a laminar flame environment at initial equivalence ratios of 2, 3, and 7 and to isolate the factors attributable to chemical structure of the fuel. The equivalence ratio was changed by altering the fuel flow rate, while maintaining the air flow rate constant. The global CO emission index of the PME flames was significantly lower than that of the diesel flames; however, the global NO emission index was comparable. The radiative fraction of heat release and the soot volume fraction were lower for the PME flames compared to those in the diesel flames. The peak temperatures were comparable in both flames at an equivalence ratio of 2, but at higher equivalence ratios, the peak temperatures in the PME flames were higher. The measurements highlight the differences in the combustion properties of biofuels and petroleum fuels and the coupling effects of equivalence ratio.

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.

scholarly journals Soot Volume Fraction Measurements by Auto-Compensating Laser-Induced Incandescence in Diffusion Flames Generated by Ethylene Pool Fire

2021 ◽  
Vol 7 ◽  
Author(s):  
Juan J. Cruz ◽  
Ignacio Verdugo ◽  
Nicolás Gutiérrez-Cáceres ◽  
Felipe Escudero ◽  
Rodrigo Demarco ◽  
...  
Keyword(s):  
Burning Rate ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Air Entrainment ◽  
Pool Fire ◽  
Mass Burning Rate ◽  
Data Set ◽  
Pool Surface ◽  
Laser Induced Incandescence ◽  
Radiation Feedback

The main characteristics of pool fire flames are flame height, air entrainment, pulsation of the flame, formation and properties of soot particles, mass burning rate, radiation feedback to the pool surface, and the amount of pollutants including soot released to the environment. In this type of buoyancy controlled flames, the soot content produced and their subsequent thermal radiation feedback to the pool surface are key to determine the self-sustainability of the flame, their mass burning rate and the heat release rate. The accurate characterization of these flames is an involved task, specially for modelers due to the difficulty of imposing adequate boundary conditions. For this reason, efforts are being made to design experimental campaigns with well-controlled conditions for their reliable repeatability, reproducibility and replicability. In this work, we characterized the production of soot in a surrogate pool fire. This is emulated by a bench-scale porous burner fueled with pure ethylene burning in still air. The flame stability was characterized with high temporal and spatial resolution by using a CMOS camera and a fast photodiode. The results show that the flame exhibit a time-varying propagation behavior with a periodic separation of the reactive zone. Soot volume fraction distributions were measured at nine locations along the flame centerline from 20 to 100 mm above the burner exit using the auto-compensating laser-induced incandescence (AC-LII) technique. The mean, standard deviation and probability density function of soot volume fraction were determined. Soot volume fraction presents an increasing tendency with the height above the burner, in spite of a local decrease at 90 mm which is approximately the position separating the lower and attached portion of the flame from the higher more intermittent one. The results of this work provide a valuable data set for validating soot production models in pool fire configurations.

Formation of Soot in Ethylene-Air Partially Premixed Flames Over a Wide Range of Premixedness

2017 ◽  
Author(s):  
Aritra Chakraborty ◽  
Satya R. Chakravarthy
Keyword(s):  
Volume Fraction ◽  
Premixed Flames ◽  
Soot Volume Fraction ◽  
Premixed Flame ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Wide Range ◽  
Partially Premixed Flames ◽  
Laser Induced Incandescence ◽  
Partially Premixed

This paper reports an investigation of soot formation in ethylene-air partially premixed flames over a wide range of premixedness. An axisymmetric co-flow configuration is chosen to establish partially premixed flames from the fully non-premixed to fully premixed conditions. Reducing the fuel flow rate as a percentage of the maximum from the core stream and supplying the same to the annular stream leads to stratification of the reactant concentrations. The thermal power, overall equivalence ratio, and the average velocity in the both streams are maintained constant under all conditions. The soot volume fraction is estimated by light attenuation method, and laser induced incandescence is performed to map the soot distribution in the flow field. The soot volume fraction is observed to exhibit a ‘S’-type trend as the conditions are traversed from near the premixed to the non-premixed regimes. That is, when traversing from the non-premixed to near-premixed regime, below 60% fuel flow rate in core, the soot volume fraction drops drastically. The onset of sooting in the partially premixed flames is clearly seen to be at the tip of the rich-premixed flame branch of their triple flame structure, which advances upstream towards the base of the flame as the premixing is reduced. The ‘S’-type variation is clearly the effect of partial premixing, more specifically due to the presence of the lean premixed flame branch of the triple flame. Laser induced incandescence intensities are insufficient to capture the upstream advance of the soot onset with decreased premixedness. So, a quick and inexpensive technique to isolate soot luminescence through flame imaging is presented in the paper involving quasi-simultaneous imaging with a 650 nm and a BG-3 filter using a normal color camera.

Effects of Jet Reynolds Number on the Performance of Axisymmetric and Nonaxisymmetric Gas Burner Flames

1999 ◽  
Author(s):  
Azfar Kamal ◽  
S. R. Gollahalli
Keyword(s):  
Reynolds Number ◽  
Heat Release ◽  
Flame Temperature ◽  
Air Entrainment ◽  
Flame Length ◽  
Temperature Profiles ◽  
Jet Flame ◽  
Burner Exit ◽  
Equivalent Area ◽  
Emission Index

Abstract An investigation of the effects of burner exit Reynolds number (9,400–19,000) on the relative effects of burner geometry (circular and elliptic with an aspect ratio 2–4) in a propane jet flame is presented. Circular and elliptic burners of the equivalent area of a circular burner of diameter 5.02 mm were studied. Air entrainment into the nonreacting jets, emission indices of NO, NO2, and CO, visible flame length, flame temperature profiles, radiative fraction of heat release, and soot concentration were measured. Results show that an increase in Re decreases the benefits of higher air entrainment into the flame due to elliptic burner geometry. Similarly, the effects of changes in NO and CO emission indices level off at higher burner Re. The measurements of visible flame length, radiative fraction flame heat release, temperature profiles, and soot concentrations corroborate and offer the explanations for the observed emission index results.

scholarly journals Soot Emission Reduction in a Biogas-DME Hybrid Dual-Fuel Engine

2020 ◽  
Vol 10 (10) ◽  
pp. 3416
Author(s):  
Bui Van Ga ◽  
Pham Quoc Thai
Keyword(s):  
Equivalence Ratio ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Pollutant Emissions ◽  
Dual Fuel ◽  
Soot Emission ◽  
Combustion Mode ◽  
Operating Condition ◽  
Diesel Injection ◽  
Combustion Properties

Combustion characteristics and harmful emissions with emphasized soot emission in the new concept of a biogas-dimethyl ether (DME) hybrid dual-fuel engine were analyzed. The effects of DME content, biogas compositions and diesel injection were examined. At any biogas composition, a rise in DME content in the fuel mixture leads to an increase in indicative engine cycle work (Wi) and NOx but a decrease in CO and soot volume fraction (fv). The effects of DME on Wi and soot volume fraction are more significant for poor biogas than for rich biogas, contrary to its effect tendency on CO and NOx concentrations. With a given operating condition and DME content, the biogas compositions slightly affect the performance and emission of a biogas-DME hybrid dual-fuel engine. At a fixed global equivalence ratio, the reduction of diesel injection leads to an increase in Wi and NOx concentration but a decrease in CO and soot volume fraction. The lower the diesel injection is, the more significant the effects of DME content on the combustion properties and pollutant emissions are. At a given operating condition and the same global equivalence ratio, the biogas-DME PCCI combustion mode is more advantageous than biogas-DME dual-fuel combustion mode. The substitution of diesel pilot ignition by DME pilot ignition in a biogas-DME hybrid dual engine is the optimal solution for both performance improvement and pollution emissions reduction.

Combustion Characteristics of Partially Premixed Prevaporized Palm Methyl Ester and Jet A Fuel Blends

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
A. Balakrishnan ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Equivalence Ratio ◽  
Volume Concentration ◽  
Laminar Flame ◽  
Combustion Characteristics ◽  
Phase Reaction ◽  
No Emission ◽  
Combustion Properties ◽  
Emission Index ◽  
Palm Methyl Ester

Palm methyl ester (PME) is an attractive alternate biofuel produced by the transesterification of palm oil with methanol. This paper is a sequel to our earlier papers on the comparison of the flame structure and emission characteristics of neat PME with those of petroleum-derived fuels (No. 2 diesel and neat Jet A). Blends of prevaporized Jet A fuel and PME (25%, 50%, and 75% by volume) were studied in a laminar flame environment at burner-exit equivalence ratios of 2, 3, and 7. The global combustion characteristics including flame length, CO and NO emission indices, radiative heat fraction, and in-flame profiles of species concentration (CO, CO2, NO, and O2), temperature, and soot volume concentration were measured. The global CO emission index decreased significantly with the PME content in the blend at an equivalence ratio of 7; a 30% reduction was observed with the addition of 25% PME by volume, and a further reduction of 25% was observed with the addition of another 25% PME. The global NO emission index of the neat PME flame was 35% lower than that of the Jet A flame at an equivalence ratio of 2. The near-burner homogeneous gas-phase reaction zone increased in length with the addition of PME at all equivalence ratios. The concentration measurements highlighted the nonmonotonic variation of properties with the volume concentration of PME in the fuel blend. The fuel-bound oxygen and hydrogen of PME affected the combustion properties significantly.

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