An Experimental Study on Combustion Dynamics and NOx Emission of a Swirl Stabilized Combustor with Secondary Fuel Injection

Biodiesel has gained popularity in diesel engines as a result of the rapid decline of fossil fuels and population growth. The processing of biodiesel from non-edible Moringa Oleifera was investigated using a single-step transesterification technique. Both fuels had their key physicochemical properties measured and investigated. In a common-rail diesel engine, the effects of MB50 fuel blend on the symmetric characteristics of engine-out responses were evaluated under five load settings and at 1000 rpm. As compared to standard diesel, MB50 increased brake thermal efficiency (BTE), and nitrogen oxides (NOx) emissions while lowering brake specific fuel consumption (BSFC), and smoke emissions for all engine loads. A further study of injection pressure and start of injection (SOI) timing for MB50 fuel was optimized using response surface methodology (RSM). The RSM optimization resulted in improved combustion dynamics due to symmetry operating parameters, resulting in a simultaneous decrease in NOx and smoke emissions without sacrificing BTE. RSM is an efficient optimization method for achieving optimal fuel injection parameter settings, as can be deduced. As a result, a clearer understanding of the use of MB50 fuel in diesel engines can be given, allowing for the best possible engine efficiency.

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Experimental Study of Catalyzed Diesel Particulate Filter with Exhaust Fuel Injection System for Heavy-Duty Diesel Engines

10.4271/2014-01-1496 ◽

2014 ◽

Cited By ~ 5

Author(s):

Tao Tang ◽

Dongxiao Cao ◽

Jun Zhang ◽

Yan-guang Zhao ◽

Shi-jin Shuai

Keyword(s):

Experimental Study ◽

Diesel Particulate Filter ◽

Fuel Injection ◽

Injection System ◽

Particulate Filter ◽

Fuel Injection System ◽

Heavy Duty ◽

Diesel Particulate ◽

Heavy Duty Diesel ◽

Catalyzed Diesel Particulate Filter

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Fuel NOx reduction by the combination of air staging and secondary fuel injection.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.52.3075 ◽

1986 ◽

Vol 52 (480) ◽

pp. 3075-3083

Author(s):

Tatsuyuki OKAMOTO ◽

Toshimi TAKAGI ◽

Satoshi FUJIWARA

Keyword(s):

Fuel Injection ◽

Nox Reduction ◽

Secondary Fuel ◽

Air Staging ◽

Fuel Nox

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Combustion Instability and Emission Control by Pulsating Fuel Injection

Journal of Turbomachinery ◽

10.1115/1.2749292 ◽

2008 ◽

Vol 130 (1) ◽

Cited By ~ 12

Author(s):

Christian Oliver Paschereit ◽

Ephraim Gutmark

Keyword(s):

High Frequency ◽

Fuel Injection ◽

Low Frequency ◽

Nox Emissions ◽

Modulation Amplitude ◽

Pulsation Frequency ◽

Symmetric Mode ◽

Instability Mode ◽

Secondary Fuel ◽

Symmetric Instability

Open-loop control methodologies were used to suppress symmetric and helical thermoacoustic instabilities in an experimental low-emission swirl-stabilized gas-turbine combustor. The controllers were based on fuel (or equivalence ratio) modulations in the main premixed combustion (premixed fuel injection (PMI)) or, alternatively, in the secondary pilot fuel. PMI included symmetric and asymmetric fuel injection. The symmetric instability mode responded to symmetric excitation only when the two frequencies matched. The helical fuel injection affected the symmetric mode only at frequencies that were much higher than that of the instability mode. The asymmetric excitation required more power to obtain the same amount of reduction as that required by symmetric excitation. Unlike the symmetric excitation, which destabilized the combustion when the modulation amplitude was excessive, the asymmetric excitation yielded additional suppression as the modulation level increased. The NOx emissions were reduced to a greater extent by the asymmetric modulation. The second part of the investigation dealt with the control of low frequency symmetric instability and high frequency helical instability by the secondary fuel injection in a pilot flame. Adding a continuous flow of fuel into the pilot flame controlled both instabilities. However, modulating the fuel injection significantly decreased the amount of necessary fuel. The reduced secondary fuel resulted in a reduced heat generation by the pilot diffusion flame and therefore yielded lower NOx emissions. The secondary fuel pulsation frequency was chosen to match the time scales typical to the central flow recirculation zone, which stabilizes the flame in the burner. Suppression of the symmetric mode pressure oscillations by up to 20dB was recorded. High frequency instabilities were suppressed by 38dB, and CO emissions reduced by using low frequency modulations with 10% duty cycle.

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