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 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 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.

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 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.

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

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Aritra Chakraborty ◽  
Satya R. Chakravarthy
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Premixed Flames ◽  
Soot Volume Fraction ◽  
Premixed Flame ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Wide Range ◽  
Partially Premixed Flames ◽  
Partially Premixed

This paper reports an investigation of soot formation in ethylene–air partially premixed flames (PPFs) over a wide range of premixedness. An axisymmetric co-flow configuration is chosen to establish PPFs from the fully nonpremixed 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 both the streams are maintained constant under all conditions. The soot volume fraction is estimated by light attenuation method, and laser-induced incandescence (LII) is performed to map the soot distribution in the flow field. The soot volume fraction is observed to exhibit an “S”-type trend as the conditions are traversed from near the premixed to the nonpremixed regimes. That is, when traversing from the nonpremixed to near-premixed regime, below 60% fuel flow rate in core, the soot volume fraction drops drastically. The onset of sooting in the PPFs is clearly seen to be at the tip of the rich-premixed flame (RPF) branch of their triple flame structure, which advances upstream toward 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 (LPF) branch of the triple flame. LII 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.

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.

Combustion Properties of Spray Flames of Canola Methyl Ester and Diesel Blends

2011 ◽  
Author(s):  
Cristian Aldana ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Flame Temperature ◽  
Combustion Products ◽  
Phase Reaction ◽  
Fuel Blend ◽  
Fuel Blends ◽  
No Formation ◽  
Spray Flames ◽  
Combustion Properties ◽  
No Emissions

Canola methyl ester (CME) is a biofuel that is produced by the transesterification of canola oil; it is renewable, carbon-neutral and low in sulfur content. The objective of this study was to document the combustion characteristics of spray flames of CME and No 2 diesel (petroleum fuel) blends. Three blends with 25%, 50% and 75% volume concentration of CME were studied. The fuel was atomized and mixed with air in a heated environment at a supply equivalence ratio of 0.62. Measurements of global CO and NO emissions, inflame temperature and in-flame concentrations of combustion products were made. The near-injector homogeneous gas-phase reaction zone increased in size with the addition of CME. The global CO and NO emissions decreased with the increase in CME content in the fuel blend. The in-flame NO concentration profiles and flame temperature profiles followed similar trends, suggesting that the thermal mechanism of NO formation was dominant in these flames.

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.

Two-Dimensional Imaging of Soot Volume Fraction in Pulsed Diffusion Flames by Laser-Induced Incandescence

2006 ◽  
Author(s):  
H. Sapmaz ◽  
C. Ghenai
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Volume Fraction ◽  
Two Dimensional ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Laser Induced Incandescence ◽  
Pulsed Flames

Laser-Induced Incandescence (LII) is used in this study to measure soot volume fractions in steady and flickering ethylene diffusion flames burning at atmospheric pressure. Better understanding of flickering flame behavior also promises to improve understanding of turbulent combustion systems. A very-high-speed solenoid valve is used to force the fuel flow rate with frequencies between 10 Hz and 200 Hz with the same mean fuel flow rate of steady flame. Periodic flame flickers are captured by two-dimensional phase-locked emission and LII images for eight phases (0°–360°) covering each period. LII spectra scan for minimizing C2 swan band emission and broadband molecular florescence, a calibration procedure using extinction measurements, and corrections for laser extinction and LII signal trapping are carried out towards developing reliable LII for quantitative applications. A comparison between the steady and pulsed flames results and the effect of the oscillation frequency on soot volume fraction for the pulsed flames are presented.

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