Simultaneous Imaging of OH* Chemiluminescence and Flame Luminosity of Diesel and Biodiesel Spray Combustion

2011 ◽  
Author(s):  
Ji Zhang ◽  
Tiegang Fang
Keyword(s):  
Ambient Temperature ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Combustion Process ◽  
Spray Combustion ◽  
Chemiluminescence Intensity ◽  
High Temperature Reaction ◽  
The Impact

The research on the spray combustion of diesel and biodiesel is vital to the understanding of emission formation and optimal utilization of fuel. This paper studies the biodiesel and diesel spray combustion in a constant volume chamber under different simulated diesel engine conditions. The ambient temperature at fuel injection varied from 800K to 1200K, while the ambient oxygen concentration was maintained at 21%. Simultaneous high speed imaging of OH* chemiluminescence and flame luminosity was employed to visualize the whole combustion process. Heat release rate was analyzed based on the measured combustion pressure. The apparent heat release rate analysis shows that biodiesel has a shorter ignition delay time than diesel, and biodiesel has a smaller cumulative heat release value due to its lower heating value. The overlaying image of OH* chemiluminescence and flame luminosity clearly identifies the high temperature reaction regions and soot formation regions. The line-of-sight images agree with the published observation that the hydroxyl radical is formed on the lean side of the flame edge. Decreasing ambient temperature greatly reduces the OH* chemiluminescence intensity of the diesel combustion, while the impact is smoother and milder for biodiesel combustion. Biodiesel shows a significantly lower level of flame luminosity than diesel under all conditions. These combined observations lead to a speculation that the soot oxidation process may serve as an important contributor to OH* chemiluminescence intensity for late stage combustion, and biodiesel shows a tendency to produce less soot than diesel under the investigated conditions.

Effects of Ambient Temperature and Oxygen Concentration on Soot Evolution in Diesel Spray Combustion

Volume 4 ◽  
2004 ◽  
Author(s):  
Yi Xu ◽  
Chia-Fon F. Lee
Keyword(s):  
Ambient Temperature ◽  
Heat Release ◽  
Oxygen Concentration ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Premixed Combustion ◽  
Ambient Oxygen ◽  
Lower Heat ◽  
Soot Measurement

A newly developed Forward Illumination Light Extinction (FILE) soot measurement technique was applied in a constant volume spray chamber to study the effects of ambient temperature and oxygen concentration on soot evolution in diesel combustion. The FILE technique with the capability of two-dimensional time-resolved quantitative soot measurement provides the much-needed information to investigate the soot formation mechanism. The ambient temperatures of 1200K, 1000K and 800K were tested to study the temperature effects on soot formation. A decrease of ambient temperature results in a longer ignition delay, which promotes a larger premixed combustion zone combining with higher heat release rates. The change of ambient temperature from 1200K to 800K increases the fuel portion burnt in the premixed combustion period. At 800K, combustion is dominated by the premixed combustion and much less soot is formed. Diesel combustion with 21% and 15% ambient oxygen concentration was also studied. With lower ambient oxygen concentration, the combustion process is basically not changed, but expands into a longer time span with a lower heat release rate. The lower heat release rate results in a lower flame temperature, which benefits the NOx emission control. However, with about the same amount of soot within the flame, and much longer soot life, soot has more chance to escape to the exhaust.

Influence of the Spatial and Temporal Interaction Between Diesel Pilot and Directly Injected Natural Gas Jet on Ignition and Combustion Characteristics

2017 ◽  
Author(s):  
Georg Fink ◽  
Michael Jud ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Gas Jet ◽  
Injection Timing ◽  
Release Rates ◽  
Temporal Interaction ◽  
The Impact

In this paper, pilot-ignited high pressure dual-fuel (HPDF) combustion of a natural gas jet is investigated on a fundamental basis by applying two separate single-hole injectors to a rapid compression expansion machine (RCEM). A Shadowgraphy system is used for optical observations, and the combustion progress is assessed in terms of heat release rates. The experiments focus on the combined influence of injection timing and geometrical jet arrangement on the jet interaction and the impact on the combustion process. In a first step, the operational range for successful pilot self-ignition and transition to natural gas jet combustion is determined, and the restricting phenomena are identified by analyzing the shadowgraph images. Within this range, the combustion process is assessed by evaluation of ignition delays and heat release rates. Strong interaction is found to delay or even prohibit pilot ignition, while it facilitates a fast and stable onset of the gas jet combustion. Furthermore, it is shown that the heat release rate is governed by the time of ignition with respect to the start of natural gas injection — as this parameter defines the level of premixing. Evaluation of the time of gas jet ignition within the operability map can therefore directly link a certain spatial and temporal interaction to the resulting heat release characteristics. It is finally shown that controlling the heat release rate through injection timing variation is limited for a certain angle between the two jets.

Fundamental Study of Diesel-Piloted Natural Gas Direct Injection Under Different Operating Conditions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Georg Fink ◽  
Michael Jud ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Gas Jet ◽  
Ignition And Combustion

Natural gas as an alternative fuel in engine applications substantially reduces both pollutant and greenhouse gas emissions. High pressure dual fuel (HPDF) direct injection of natural gas and diesel pilot has the potential to minimize methane slip from gas engines and increase the fuel flexibility, while retaining the high efficiency of a diesel engine. Speed and load variations as well as various strategies for emission reduction entail a wide range of different operating conditions. The influence of these operating conditions on the ignition and combustion process is investigated on a rapid compression expansion machine (RCEM). By combining simultaneous shadowgraphy (SG) and OH* imaging with heat release rate analysis, an improved understanding of the ignition and combustion process is established. At high temperatures and pressures, the reduced pilot ignition delay and lift-off length minimize the effect of natural gas jet entrainment on pilot mixture formation. A simple geometrical constraint was found to reflect the susceptibility for misfiring. At the same time, natural gas ignition is delayed by the early pilot ignition close to the injector tip. The shape of heat release is only marginally affected by the operating conditions and mainly determined by the degree of premixing at the time of gas jet ignition. Luminescence from the sooting natural gas flame is generally only detected after the flame extends across the whole gas jet at peak heat release rate. Termination of gas injection at this time was confirmed to effectively suppress soot formation, while a strongly sooting pilot seems to intensify soot formation within the natural gas jet.

Effect of type of organic modifier on the clay layered-based nanocomposites flammability and toxic gases emission

2020 ◽  
pp. 089270572093593
Author(s):  
Nour Fathi Attia ◽  
M Nour ◽  
M Hassan ◽  
G Mohamed ◽  
H Oh ◽  
...  
Keyword(s):  
Heat Release ◽  
Polymer Nanocomposites ◽  
Heat Release Rate ◽  
Release Rate ◽  
Mass Loss Rate ◽  
Combustion Process ◽  
Average Mass ◽  
Toxic Gases ◽  
Clay Layers ◽  
The Impact

Well dispersed polyethylene (PE) nanocomposites were developed. Montmorillonite (MMT) as aluminosilicate clay layers was modified using organic silanes of different side chains. The MMT was grafted using 3-(trimethoxysilyl)propylamine, N-[3-(trimethoxysilyl)propyl]ethylenediamine, and trimethoxyvinylsilane. The modification process of MMT using organic different silanes was elucidated using microscopic, thermogravimetric, spectroscopic, and X-ray diffraction tools. Then, the developed organoclays were dispersed uniformly in PE matrix producing well exfoliated and dispersed polymer nanocomposites. The mass loadings of dispersed organoclay were varied and the impact of organic silane structure was studied. Thermal stability and flammability properties of the developed polymer nanocomposites were evaluated. The peak heat release rate and average heat release rate were reduced by 48% and 61%, respectively compared to virgin polymer. Also, the average mass loss rate was significantly reduced by 50%. This is in addition to reduction in emission of carbon monoxide (CO) and carbon dioxide (CO2) by 45% and 56%, respectively. The effect of side chain of organosilane on the performance of modified clay layers was studied. The toxicity of gases evolved during combustion process of PE and their polymer nanocomposites were evaluated using Fourier transform infrared connected to cone calorimeter. Additionally, the influence of organic silane on the pyrolysis and toxic gases emission was further studied.

Fundamental Study of Diesel-Piloted Natural Gas Direct Injection Under Different Operating Conditions

2018 ◽  
Author(s):  
Georg Fink ◽  
Michael Jud ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Gas Jet ◽  
Ignition And Combustion

Natural gas as an alternative fuel in engine applications substantially reduces both pollutant and greenhouse gas emissions. High pressure dual fuel direct injection of natural gas and Diesel pilot has the potential to minimize methane slip from gas engines and increase the fuel flexibility, while retaining the high efficiency of a Diesel engine. Speed and load variations as well as various strategies for emission reduction entail a wide range of different operating conditions. The influence of these operating conditions on the ignition and combustion process is investigated on a rapid compression expansion machine. By combining simultaneous Shadowgraphy and OH* imaging with heat release rate analysis, an improved understanding of the ignition and combustion process is established. At high temperatures and pressures the reduced pilot ignition delay and lift-off length minimize the effect of natural gas jet entrainment on pilot mixture formation. A simple geometrical constraint was found to reflect the susceptibility for misfiring. At the same time natural gas ignition is delayed by the early pilot ignition close to the injector tip. The shape of heat release is only marginally affected by the operating conditions and mainly determined by the degree of premixing at the time of gas jet ignition. Luminescence from the sooting natural gas flame is generally only detected after the flame extends across the whole gas jet at peak heat release rate. Termination of gas injection at this time was confirmed to effectively suppress soot formation, while a strongly sooting pilot seems to intensify soot formation within the natural gas jet.

Influence of the Indicator Channel and Indicator Valve on the Heat Release Characteristics of Medium Speed Marine Diesel Engines

2013 ◽  
Vol 588 ◽  
pp. 149-156 ◽  
Author(s):  
Stanisław Polanowski ◽  
Rafał Pawletko ◽  
Kazimierz Witkowski
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Diesel Engines ◽  
Diagnostic Information ◽  
Injection System ◽  
Indicator Diagram ◽  
Medium Speed ◽  
Marine Diesel ◽  
The Impact

Analysis of the indicator diagram is the basis of technical state evaluation of marine diesel engines. The indicator diagram contains a large amount of diagnostic information. A major problem for the diagnostic use of the indicator diagram is the pressure sensor location. Indicator channel and valve may introduce significant distortions in the resulting pressure. The paper presents results of research conducted on the medium speed laboratory engine Al 25/30. Pressure measurement (indication) was made by the sensor placed directly in the cylinder (instead of starting air valve), before the indicator valve (with special Kistler adapter) and on the indicator valve. Distortion of heat release characteristics for the sensor placed on the indicator valve is important, but it is estimated that diagnostic information is not erased. For medium speed engines is to be expected the use of a portable pressure sensors placed on the indicator valve. For this reason, further research is needed to assess the impact of channels and valves on different cylinders. During the research the course of heat release rate q and the heat released Q were determined. The curve of heat release rate q is a full equivalent to fuel injection pressure curve in the fuel pipes. It allows identification of the failure of the injection system. The curve of Q allows such determination and assessment of internal efficiency of the cylinder.

scholarly journals Analysis on Pattern of Heat Release Rate in Two-Stroke Slow Speed Diesel Engine (2nd Report: Prediction of the Combustion Process)

2003 ◽  
Vol 38 (5) ◽  
pp. 303-308
Author(s):  
Takeshi Imahashi ◽  
Eiji Tomita ◽  
Sadami Yoshiyama ◽  
Kouji Moriyama
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Slow Speed

scholarly journals Effect of ratio between incoming cool air and outgoing hot gases on behaviour of compartment fire

2019 ◽  
pp. 326-326
Author(s):  
Olivier Zatao-Samedi ◽  
Abbo Oumarou ◽  
Jean M’Boliguipa ◽  
Mvogo Onguene ◽  
Ruben Mouangue
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Room Temperature ◽  
Data Acquisition System ◽  
Main Element ◽  
Compartment Fire ◽  
Release Rates ◽  
The Impact ◽  
Reduced Scale

Many factors have an influence on the development of compartment fire notably on its heat release rate as well as on its capability to propagate and become a flashover situation. The main element which rapidly conveys fire from a compartment to another is hot smoke flowing out through openings of the compartment source of fire. The present work aims to experiment the impact of the variation of heat release rate of the source on the behaviour of fire. So, five fire tests with different heat release rates were thus carried out in a reduced scale room. Temperature of burned gases inside the room, were measured during tests by sensors connected to a data acquisition system. Results revealed that temperature of burned gases as well as its content in carbon monoxide, evolves differently according to two ranges of the incoming air/outgoing gases ratio. The first range of which the ratio is lower than 2, corresponds to the case where both parameters decrease rapidly. The second range of which the ratio is higher than 2, corresponds to the case where both parameters decrease moderately. The transition from the first to the second range, points out the passing from the ventilation-controlled fire to the fuel-controlled fire. A relation expressing the variation of the mass flow rate of outgoing burned gases according to the heat release rate of the fire source has been given.

Experimental and Theoretical Optimization of Combustion Chamber and Fuel Distribution for the Low Emission DI Diesel Engine

2001 ◽  
Author(s):  
Yoshiyuki Kidoguchi ◽  
Michiko Sanda ◽  
Kei Miwa
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Combustion Chamber ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Mixture Distribution ◽  
Initial Mixture ◽  
Injection Timing ◽  
Initial Heat

Abstract This study investigated the effect of combustion chamber geometry and initial mixture distribution on combustion process in a direct-injection diesel engine by means of experiment and CFD calculation. The high squish combustion chamber with squish lip could produce simultaneous reduction of NOx and particulate emissions with retarded injection timing in the real engine experiment. According to the CFD computation, the high squish combustion chamber with central pip is effective to continue combustion under the squish lip until the end of combustion and the combustion region forms rich and high turbulence atmosphere, which reduces NOx emissions. This chamber can also reduce initial burning because combustion continues under the squish lip. The CFD computation is also carried out in order to investigate the effect of initial mixture distribution on combustion process. The results suggest that mixture distribution affects the history of heat release rate. When fuel is distributed in the bottom or wide region in the combustion chamber, burned gas tends to spread to the cavity center and initial heat release rate becomes high. On the contrary, the high squish combustion chamber with central pip produces lower initial heat release rate because combustion with local rich condition continues long under the squish lip. Diffusion burning is promoted by high swirl motion in this chamber with keeping lower initial heat release rate.

scholarly journals Non-Chloride in Situ Preparation of Nano-Cuprous Oxide and Its Effect on Heat Resistance and Combustion Properties of Calcium Alginate

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1760 ◽  
Author(s):  
Peiyuan Shao ◽  
Peng Xu ◽  
Lei Zhang ◽  
Yun Xue ◽  
Xihui Zhao ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Heat Release ◽  
Hybrid Materials ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cuprous Oxide ◽  
Calcium Alginate ◽  
Combustion Process ◽  
Protective Layer ◽  
Combustion Properties

With Cu2+ complexes as precursors, nano-cuprous oxide was prepared on a sodium alginate template excluded of Cl− and based on which the calcium alginate/nano-cuprous oxide hybrid materials were prepared by a Ca2+ crosslinking and freeze-drying process. The thermal degradation and combustion behavior of the materials were studied by related characterization techniques using pure calcium alginate as a comparison. The results show that the weight loss rate, heat release rate, peak heat release rate, total heat release rate and specific extinction area of the hybrid materials were remarkably lower than pure calcium alginate, and the flame-retardant performance was significantly improved. The experimental data indicates that nano-cuprous oxide formed a dense protective layer of copper oxide, calcium carbonate and carbon by lowering the initial degradation temperature of the polysaccharide chain during thermal degradation and catalytically dehydrating to char in the combustion process, and thereby can isolate combustible gases, increase carbon residual rates, and notably reduce heat release and smoke evacuation.

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