Study of the Characteristic of Diesel Spray Combustion and Soot Formation Using Laser-Induced Incandescence (LII)

2012 ◽  
Author(s):  
Xiaobei Cheng ◽  
Liang Chen ◽  
Fangqin Yan
Keyword(s):  
Soot Formation ◽  
Diesel Spray ◽  
Spray Combustion ◽  
Laser Induced Incandescence

Two-dimensional imaging of ignition and soot formation processes in a diesel flame

2005 ◽  
Vol 6 (1) ◽  
pp. 21-42 ◽  
Author(s):  
H Kosaka ◽  
T Aizawa ◽  
T Kamimoto
Keyword(s):  
Soot Formation ◽  
Diesel Spray ◽  
Oxidation Reactions ◽  
Soot Particles ◽  
Nozzle Orifice ◽  
Spray Flame ◽  
Soot Precursor ◽  
Planar Laser ◽  
Laser Induced Incandescence ◽  
Ambient Gas

The processes of ignition and formation of soot precursor and soot particles in a diesel spray flame achieved in a rapid compression machine (RCM) were imaged two-dimensionally using the laser sheet techniques. For the two-dimensional imaging of time and of location where ignition first occurs in a diesel spray, planar laser-induced fluorescence (PLIF) of formaldehyde was applied to a diesel spray in an RCM. Formaldehyde has been hypothesized to be one of the stable intermediate species marking the start of oxidation reactions in a transient spray under compression ignition conditions. In this study, the laser-induced fluorescence (LIF) images of the formaldehyde formed in a diesel fuel spray during the ignition process have been obtained by exciting formaldehyde with the third harmonic of a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser. The LIF images of formaldehyde in a spray revealed that the time when the first fluorescence is detected is almost identical with the time when the total heat release due to low-temperature oxidation reactions equals the heat absorption by fuel vaporization in the spray. The formaldehyde level rose steadily until the high-temperature reaction phase of diesel spray ignition. At the start of this ‘hot-ignition’ phase, the formaldehyde concentration fell rapidly, thus signalling the end of the low-temperature ignition phase. Increases in the initial ambient gas temperatures advanced the hot-ignition starting time. The first hot ignition occurred in the periphery of spray head at initial ambient gas temperatures between 580 and 660 K. When the ambient gas temperature was increased to 790 K, the position of the first ignition moved to the central region of the spray head. For the investigation of soot formation processes in a diesel spray flame, simultaneous imaging of the soot precursor and soot particles in a transient spray flame in an RCM was conducted by PLIF and by planar laser-induced incandescence (PLII) techniques. The third harmonic (355 nm) and the fundamental (1064 nm) laser pulses from an Nd:YAG laser, between which a delay of 44 ns was imposed by 13.3 m of optical path difference, were used to excite LIF from the soot precursor and laser-induced incandescence (LII) from soot particles in the spray flame. The LIF and the LII were separately imaged by two image-intensified charge-coupled device cameras with identical detection wavelengths of 400 nm and bandwidths of 80 nm. The LIF from the soot precursor was mainly located in the central region of the spray flame between 40 and 55 mm (between 270 and 370 times the nozzle orifice diameter d°) from the nozzle orifice. The LII from soot particles was observed to surround the soot precursor LIF region and to extend downstream. The first appearance of the LIF from the soot precursor in the spray flame preceded the appearance of the LII from soot particles. The intensity of the LIF from the soot precursor reached its maximum immediately after rich premixed combustion. In contrast, the intensity of the LII from soot particles increased gradually and reached its maximum after the end of injection. Measured LIF spectra, of the soot precursor in the spray flame, were very broad with the peak between 430 and 460 nm.

Evaluation of Soot Production Near a Cold Surface for an Impinged Diesel Spray Combustion

2020 ◽  
Author(s):  
Zhihao Zhao ◽  
Le Zhao ◽  
Seong-Young Lee
Keyword(s):  
Mass Fraction ◽  
Internal Combustion Engines ◽  
Soot Formation ◽  
Leading Edge ◽  
Ambient Air ◽  
Diesel Spray ◽  
Spray Combustion ◽  
Ambient Conditions ◽  
Cold Surface ◽  
Soot Mass

Abstract Spray impingement in internal combustion engines has received great attentions. Such a phenomenon is especially important for diesel spray because the spray and combustion characteristics are significantly altered by the impingement. In this study, numerical investigations of impinged reacting spray jets in a constant volume combustion chamber were performed to understand the spray and flame structure under high pressure and high temperature conditions. The 3-D computational fluid dynamics (CFD) CONVERGE code was selected as the numerical tool to perform Large-eddy simulations (LES) to understand the process of spray combustion-wall interaction. CFD models were validated against experimental results in terms of spray penetration and ignition delay at inert and reacting spray conditions. The temperature and soot mass fraction profiles near the impinging plate were investigated for 900 and 1000 K ambient conditions. It was found that soot mass fraction is generally increased near the impinging plate as the temperature is decreased. The heat transfer from the flame to the plate makes the temperature close to the wall more favorable for soot formation. A dense soot core was observed at the leading edge when the injection was still happening because the vortex there took the opportunity from existing burned gas to new fuel to meet the ambient air. A soot layer was observed stick on the wall as the air was hard to entrain the flame all the way to the plate side.

scholarly journals The effect of oxygenated fuel properties on diesel spray combustion and soot formation

2017 ◽  
Vol 180 ◽  
pp. 276-283 ◽  
Author(s):  
Wonah Park ◽  
Seunghyun Park ◽  
Rolf D. Reitz ◽  
Eric Kurtz
Keyword(s):  
Soot Formation ◽  
Fuel Properties ◽  
Diesel Spray ◽  
Spray Combustion ◽  
Oxygenated Fuel

A phenomenological model for the prediction of soot formation in diesel spray combustion

2004 ◽  
Vol 136 (3) ◽  
pp. 270-282 ◽  
Author(s):  
Feng Tao ◽  
Valeri I Golovitchev ◽  
Jerzy Chomiak
Keyword(s):  
Phenomenological Model ◽  
Soot Formation ◽  
Diesel Spray ◽  
Spray Combustion
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