Study on Diesel Low-Nitrogen or Nitrogen-Free Combustion Performance in Constant Volume Combustion Vessels and Contributory

This paper studies the combustion performance of diesel in constant volume combustion vessels under different conditions of mixed low-nitrogen (O2 and N2) or non-nitrogen (O2 and CO2) in varying proportions. The high-speed camera is used to shoot the combustion flame in the constant volume combustion vessel. The process and morphology of the combustion flame are amplified in both time and space to study and analyze the effects of different compositions and concentrations in gases on the combustion performance of diesel and conduct a study on the contributory factors in the performance of diesel with no nitrogen. According to the study, in the condition of low nitrogen, the O2 concentration is more than 60%, the ignition delay period is shortened, the combustion flame is bright and slender, it spreads quickly, and the blue flame appears when the O2 concentration reaches 70%; While for nitrogen-free combustion, only when the O2 concentration reaches 30% is the combustion close to the air condition; when the O2 concentration reaches 40%, the combustion condition is optimized obviously and the combustion flame is relatively slender compared to the air working condition. Similarly, with the increase of the O2 concentration, the ignition delay period of nitrogen-free diesel is shortened, the duration is extended, and the combustion performance is optimized. In addition, when the O2 concentration reaches 50%, with the decrease of the initial temperature, the ignition delay period is prolonged, and the duration is shortened obviously. When the temperature is lower than 700 K, there is no ignition. The increase of the diesel injection pressure is beneficial to optimize the ignition performance of diesel non-nitrogen combustion and shorten its ignition delay period and combustion duration. Related research has important guiding significance to optimize nitrogen-free combustion technology, which produces no NOx of the diesel engine.

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Simulation Study of Ignition Characteristics of Impinging Sprays in Constant Volume Chamber

Journal of University of Shanghai for Science and Technology ◽

10.51201/jusst/21/04201 ◽

2021 ◽

Vol 23 (04) ◽

pp. 70-81

Author(s):

Sanaur Rehman ◽

◽

Shah Shahood Alam ◽

Keyword(s):

Surface Temperature ◽

Simulation Study ◽

Ignition Delay ◽

Injection Pressure ◽

Delay Period ◽

Constant Volume ◽

Operating Conditions ◽

Air Pressure ◽

Hot Surface ◽

Ignition Delay Period

The present study involves the simulation of a constant volume, non-premixed, hot surface spray combustion of diesel fuel for a given set of injection pressure, compressed air pressure (cylinder air pressure) and hot surface temperature (hot plate temperature) and their effects on ignition delay period. Fuel injection pressure was varied from 100 bar – 300 bar in steps of 100 bar, cylinder air pressure in the range of 20 bar to 40 bar (in steps of 10 bar) and hot surface temperature from 623 K to 723 K (50 K steps). The problem was solved using 2D axisymmetric geometry. A structured mesh of about 1.24 lac nodal points was created and tested for grid independency. For solving flow behavior, a pressure solver was used with a turbulence model of k-ε with enhanced wall functions. While a volumetric eddy dissipation model was used to solve combustion phenomena. Ignition delay period was calculated with the help of static temperature versus time plot. It is found that keeping any two operating parameters constant, third operating parameter is inversely proportional to ignition delay period. The results of the present simulation study are in a fairly good agreement with the experimental studies at same operating conditions.

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Effect of Pilot Injection on Mixture Formation, Ignition Process and Flame Development in Diesel Combustion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.390.327 ◽

2013 ◽

Vol 390 ◽

pp. 327-332 ◽

Cited By ~ 1

Author(s):

Amir Khalid ◽

M. Jaat ◽

Izzuddin Zaman ◽

B. Manshoor ◽

Mas Fawzi

Keyword(s):

Ignition Delay ◽

High Speed ◽

Combustion Process ◽

Video Camera ◽

Delay Period ◽

Ignition Process ◽

Pilot Injection ◽

Mixture Formation ◽

Digital Video Camera ◽

Ignition Delay Period

The alternative combustion strategies with systematic control of mixture formation have provided new opportunities and considerable improvement in the combustion process and response to meet the stringent emissions standards. Purpose of this research is to investigate the influences of pilot injection on the fuel-air premixing especially during ignition delay period. During this period, the interaction between fuel spray and surrounding gas prior to ignition which linked to the improvement of mixture formation, ignition process and initial heat recovery thus predominantly influences the combustion process and exhaust emissions. This study investigates the effects of pilot injection using a rapid compression machine together with the schlieren photography and direct photography methods. The detail behavior of mixture formation during ignition delay period was investigated using the schlieren photography system with a high speed digital video camera. This method can capture spray evaporation, spray interference and mixture formation clearly with real images. Ignition process and flame development were investigated by direct photography method using a light sensitive high-speed color digital video camera. Pilot injection promotes mixture formation during ignition delay period and slower oxidation reaction and thus leads to earlier rise and lower peak heat release rate.

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Experimental investigations to predict optimistic biodiesel(s) and its optimistic operating conditions by varying ignition delay period and fuel spray pressures for lower emissions and better performance

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220917693 ◽

2020 ◽

Vol 234 (19) ◽

pp. 3890-3902

Author(s):

Vishal V Patil ◽

Ranjit S Patil

Keyword(s):

Methyl Ester ◽

Ignition Delay ◽

Seed Oil ◽

Delay Period ◽

Operating Conditions ◽

Experimental Investigations ◽

Rubber Seed Oil ◽

Rubber Seed ◽

Neem Seed Oil ◽

Ignition Delay Period

In this study, different characteristics of sustainable renewable biodiesels (those have a high potential of their production worldwide and in India) were compared with the characteristics of neat diesel to determine optimistic biodiesel for the diesel engine at 250 bar spray pressure. Optimistic fuel gives a comparatively lower level of emissions and better performance than other selected fuels in the study. Rubber seed oil methyl ester was investigated as an optimistic fuel among the other selected fuels such as sunflower oil methyl ester, neem seed oil methyl ester, and neat diesel. To enhance the performance characteristics and to further decrease the level of emission characteristics of fuel ROME, further experiments were conducted at higher spray (injection) pressures of 500 bar, 625 bar, and 750 bar with varying ignition delay period via varying its spray timings such as 8°, 13°, 18°, 23°, 28°, and 33° before top dead center. Spray pressure 250 bar at 23° before top dead center was investigated as an optimistic operating condition where fuel rubber seed oil methyl ester gives negligible hydrocarbon emissions (0.019 g/kW h) while its nitrogen oxide (NOX) emissions were about 70% lesser than those observed with neat diesel, respectively.

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