Measurements of soot temperature and KL factor for spray combustion of biomass derived renewable fuels

Energy ◽  
2015 ◽  
Vol 91 ◽  
pp. 758-771 ◽  
Author(s):  
Wei Jing ◽  
Zengyang Wu ◽  
Weibo Zhang ◽  
Tiegang Fang
Keyword(s):  
Spray Combustion ◽  
Soot Temperature ◽  
Renewable Fuels ◽  
Kl Factor

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

2016 ◽  
Author(s):  
Wei Jing ◽  
Zengyang Wu ◽  
William L. Roberts ◽  
Tiegang Fang
Keyword(s):  
Diesel Fuel ◽  
Formation Process ◽  
Fuel Injection ◽  
Soot Formation ◽  
Injection Pressure ◽  
Soot Temperature ◽  
Renewable Diesel ◽  
Constant Volume Combustion Chamber ◽  
Kl Factor ◽  
Soot Measurement

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel, however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.

Comparison of Soot Evolution Using High-Speed CMOS Color Camera and Two-Color Thermometry in an Optical Diesel Engine Fueled With B20 Biodiesel Blend and Ultra-Low Sulfur Diesel

2011 ◽  
Author(s):  
Kan Zha ◽  
Radu-Catalin Florea ◽  
Marcis Jansons
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Soot Formation ◽  
Soot Temperature ◽  
Piston Bowl ◽  
Ultra Low Sulfur Diesel ◽  
Wall Impingement ◽  
Kl Factor ◽  
Biodiesel Blend ◽  
Low Sulfur

Biodiesel is a desirable alternative fuel for the diesel engine due to its low engine-out soot emission tendency. When blended with petroleum-based diesel fuels, soot emissions generally decrease in proportion to the volume fraction of biodiesel in the mixture. While comparisons of engine-out soot measurements between biodiesel blends and petroleum-based diesel have been widely reported, in-cylinder soot evolution has not been experimentally explored to the same extent. To elucidate the soot emission reduction mechanism of biodiesel, a single-cylinder optically-accessible diesel engine was used to compare the in-cylinder soot evolution when fueled with ultra-low sulfur diesel (ULSD) to that using a B20 biodiesel blend (20% vol/vol biodiesel ASTM D6751-03A). Soot temperature and KL factors are simultaneously determined using a novel two-color optical thermometry technique implemented with a high-speed CMOS color camera having wide-band Bayer filters. The crank-angle resolved data allows quantitative comparison of the rate of in-cylinder soot formation. High-speed spray images show that B20 has more splashing during spray wall impingement than ULSD, distributing rebounding fuel droplets over a thicker annular ring interior to the piston bowl periphery. The subsequent soot luminescence is observed by high-speed combustion imaging and soot temperature and KL factor measurements. B20 forms soot both at low KL magnitudes over large areas between fuel jets, and at high values among remnants of the fuel spray, along its axis and away from the bowl edge. In contrast, ULSD soot luminescence is observed exclusively as pool burning on the piston bowl surfaces resulting from fuel wall impingement. The soot KL factor evolution during B20 combustion indicates earlier and significantly greater soot formation than with ULSD. B20 combustion is also observed to have a greater soot oxidation rate which results in lower engine-out soot emissions. Measured soot temperatures near 1875K were similar for the two fuels for the duration of combustion. For both fuels, higher fuel injection pressure led to lower late-cycle soot KL levels. The trends of soot natural luminosity correlated well with the trends of soot KL factor, suggesting that relatively simple measurements of combustion luminosity may provide somewhat quantitative information about in-cylinder soot formation and oxidation. The apparent rate of heat release (ARHR) analysis under steady skip-fire conditions indicates that B20 combustion is less sensitive to wall temperature than that observed with ULSD due to a lesser degree of pool burning. B20 was found to have both a shorter ignition delay and shorter combustion duration than ULSD.

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Kan Zha ◽  
Radu-Catalin Florea ◽  
Marcis Jansons
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Soot Formation ◽  
Soot Temperature ◽  
Soot Emission ◽  
Piston Bowl ◽  
Crank Angle ◽  
Wall Impingement ◽  
Kl Factor ◽  
Biodiesel Blend

Biodiesel is a desirable alternative fuel for the diesel engine due to its low engine-out soot emission tendency. When blended with petroleum-based diesel fuels, soot emissions generally decrease in proportion to the volume fraction of biodiesel in the mixture. While comparisons of engine-out soot measurements between biodiesel blends and petroleum-based diesel have been widely reported, in-cylinder soot evolution has not been experimentally explored to the same extent. To elucidate the soot emission reduction mechanism of biodiesel, a single-cylinder optically-accessible diesel engine was used to compare the in-cylinder soot evolution when fueled with ultra-low sulfur diesel (ULSD) to that using a B20 biodiesel blend (20% vol./vol. biodiesel ASTM D6751-03A). Soot temperature and KL factors are simultaneously determined using a novel two-color optical thermometry technique implemented with a high-speed CMOS color camera having wide-band Bayer filters. The crank-angle resolved data allows quantitative comparison of the rate of in-cylinder soot formation. High-speed spray images show that B20 has more splashing during spray wall impingement than ULSD, distributing rebounding fuel droplets over a thicker annular ring interior to the piston bowl periphery. The subsequent soot luminescence is observed by high-speed combustion imaging and soot temperature and KL factor measurements. B20 forms soot both at low KL magnitudes over large areas between fuel jets, and at high values among remnants of the fuel spray, along its axis and away from the bowl edge. In contrast, ULSD soot luminescence is observed exclusively as pool burning on the piston bowl surfaces resulting from spray wall impingement. The soot KL factor evolution during B20 combustion indicates earlier and significantly greater soot formation than with ULSD. B20 combustion is also observed to have a greater soot oxidation rate, which results in lower late-cycle soot emissions. For both fuels, higher fuel injection pressure led to lower late-cycle soot KL levels. The apparent rate of heat release (ARHR) analysis under steady skip-fire conditions indicates that B20 combustion is less sensitive to wall temperature than that observed with ULSD due to a lesser degree of pool burning. B20 was found to have both a shorter ignition delay and shorter combustion duration than ULSD.

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Wei Jing ◽  
Zengyang Wu ◽  
William L. Roberts ◽  
Tiegang Fang
Keyword(s):  
Diesel Fuel ◽  
Formation Process ◽  
Fuel Injection ◽  
Soot Formation ◽  
Injection Pressure ◽  
Soot Temperature ◽  
Renewable Diesel ◽  
Constant Volume Combustion Chamber ◽  
Kl Factor ◽  
Soot Measurement

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case. but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel; however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.

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