Gas-to-Liquid Sprays at Different Injection and Ambient Conditions

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Dung Ngoc Nguyen ◽  
Hiroaki Ishida ◽  
Masahiro Shioji
Keyword(s):  
Oxygen Concentration ◽  
Ignition Delay ◽  
Alternative Fuels ◽  
Ambient Pressure ◽  
Cetane Number ◽  
Combustion Characteristics ◽  
Gas Oil ◽  
Ambient Conditions ◽  
Ignition Quality ◽  
Gas To Liquid

Alternative fuels exhibit potential as a clean fuel and suitable to address problems of energy security and environmental pollution. The main objective of this research was to provide the fundamental data of ignition delay and combustion characteristics for gas-to-liquid (GTL) fuels. Experiments were carried out in a constant-volume vessel under diesel-engine conditions to study the effects of various injection and ambient conditions on ignition and combustion characteristics. The results showed that all tested fuels exhibited similar ignition-delay trends: Ignition delay increased as ambient temperature, ambient pressure, and oxygen concentration decreased. The result of changing injection pressures and nozzle-hole diameters did not significantly affect ignition-delay values for all tested fuels. The variation in ignition-delay values was small at temperatures higher than 700 K but large at temperatures less than 700 K. In addition, the result showed that GTL fuels with high cetane number corresponded to shorter ignition delay and smoother heat-release rate than those for gas-oil (conventional diesel fuel) at the same temperature, pressure, and oxygen concentration. The blend GTL fuel improved ignition quality and combustion than that of gas-oil. Shadowgraph images showed that GTL fuels exhibited shorter spray penetration and mixed with the hot air quicker than gas-oil. In addition, GTL fuels showed suitability for premixed charge compression-ignition operations owing to ignitability at low temperature. The obtained results provide useful information for finding the optimal conditions for the design and control of diesel engines fuelled by synthetic GTL fuels.

Formulation of Sasol Isomerized Paraffinic Kerosene Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Ziliang Zheng ◽  
Tamer Badawy ◽  
Naeim Henein ◽  
Peter Schihl ◽  
Eric Sattler
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Cetane Number ◽  
Surrogate Fuels ◽  
Cycle Simulation ◽  
Ignition Quality ◽  
Surrogate Fuel ◽  
Ignition Quality Tester

Sasol isomerized paraffinic kerosene (IPK) is a coal-derived synthetic fuel under consideration as a blending stock with jet propellant 8 (JP-8) for use in military equipment. However, Sasol IPK is a low ignition quality fuel with derived cetane number (DCN) of 31. The proper use of such alternative fuels in internal combustion engines (ICEs) requires the modification in control strategies to operate engines efficiently. With computational cycle simulation coupled with surrogate fuel mechanism, the engine development process is proved to be very effective. Therefore, a methodology to formulate Sasol IPK surrogate fuels for diesel engine application using ignition quality tester (IQT) is developed. An in-house developed matlab code is used to formulate the appropriate mixture blends, also known as surrogate fuel. And aspen hysys is used to emulate the distillation curve of the surrogate fuels. The properties of the surrogate fuels are compared to those of the target Sasol IPK fuel. The DCNs of surrogate fuels are measured in the IQT and compared with the target Sasol IPK fuel at the standard condition. Furthermore, the ignition delay, combustion gas pressure, and rate of heat release (RHR) of Sasol IPK and its formulated surrogate fuels are analyzed and compared at five different charge temperatures. In addition, the apparent activation energies derived from chemical ignition delay of the surrogate fuel and Sasol IPK are determined and compared.

Ignition Delay and Combustion Characteristics of Gaseous Fuel Jets

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Dung Ngoc Nguyen ◽  
Hiroaki Ishida ◽  
Masahiro Shioji
Keyword(s):  
Natural Gas ◽  
Ambient Temperature ◽  
Ignition Delay ◽  
Internal Combustion Engines ◽  
Ambient Pressure ◽  
Combustion Characteristics ◽  
Spontaneous Ignition ◽  
Ambient Conditions ◽  
Mixture Formation ◽  
Gaseous Fuels

Gaseous fuels, such as hydrogen and natural gas, are utilized in internal combustion engines for spark-ignition operation. To improve thermal efficiency and to ensure control at good heat-release rates, combustion systems with direct-injection and spontaneous-ignition operation may be preferable. The main objective of this research was to provide fundamental data for the ignition and combustion of hydrogen, natural gas, and methane. Experiments were conducted in a constant-volume combustion vessel to investigate the effects of ambient temperature on ignition delay and combustion characteristics for various injector and ambient conditions. Experimental results showed that all gaseous fuels exhibited similar ignition-delay trends: ignition delay (τ) increased as ambient temperature (Ti) decreased. Among these fuels, hydrogen jets exhibited much shorter τ than natural gas and methane jets at the same Ti and could be ignited at a lower temperature, Ti=780 K. A shorter ignition delay of hydrogen may be attained by controlling the mixture formation by lowering the injection pressure (pj), enlarging the nozzle-hole diameter (dN), increasing the ambient pressure (pi), and increasing the oxygen mole fraction (rO2). In contrast, the methane jet exhibited the longest τ over the whole range of Ti and suffered from misfiring at a higher Ti of 910 K. For natural gas, ignition delay was observed to be shorter than that for methane, owing to a small amount of butane with good ignitability. More specifically, the ignition delay of natural gas differed slightly when dN and pj varied but changed drastically when pi and rO2 decreased. Based on these data, the feasibility of gaseous fuels for compression-ignition engines is discussed from the viewpoint of mixture formation and chemical reaction.

Effect of n-heptane and n-decane on exhaust odour in direct injection diesel engines

2005 ◽  
Vol 219 (4) ◽  
pp. 565-571 ◽  
Author(s):  
M M Roy
Keyword(s):  
Direct Effect ◽  
Diesel Fuel ◽  
Diesel Engines ◽  
Ignition Delay ◽  
Boiling Point ◽  
Alternative Fuels ◽  
Direct Injection ◽  
Cetane Number ◽  
Mixture Formation ◽  
Incomplete Combustion

This study investigated the effect of n-heptane and n-decane on exhaust odour in direct injection (DI) diesel engines. The prospect of these alternative fuels to reduce wall adherence and overleaning, major sources of incomplete combustion, as well as odorous emissions has been investigated. The n-heptane was tested as a low boiling point fuel that can improve evaporation as well as wall adherence. However, the odour is a little worse with n-heptane and blends than that of diesel fuel due to overleaning of the mixture. Also, formaldehyde (HCHO) and total hydrocarbon (THC) in the exhaust increase with increasing n-heptane content. The n-decane was tested as a fuel with a high cetane number that can improve ignition delay, which has a direct effect on wall adherence and overleaning. However, with n-decane and blends, the odour rating is about 0.5-1 point lower than for diesel fuel. Moreover, the aldehydes and THC are significantly reduced. This is due to less wall adherence and proper mixture formation.

An Ignition Delay Study of Category A and C Aviation Fuel

2015 ◽  
Author(s):  
Kyungwook Min ◽  
Daniel Valco ◽  
Anna Oldani ◽  
Tonghun Lee
Keyword(s):  
Ignition Delay ◽  
Cetane Number ◽  
Test Chamber ◽  
Combustion Characteristics ◽  
Aviation Fuel ◽  
Jet Fuels ◽  
Fuel Blend ◽  
Auto Ignition ◽  
Alternative Aviation Fuels ◽  
Pressure Trace

Ignition delay of category A and C alternative aviation fuels have been investigated using a rapid compression machine (RCM). Newly introduced alternative jet fuels are not yet comprehensively understood in their combustion characteristics. Two of the category C fuels that will be primarily investigated in this study are Amyris Farnesane and Gevo Jet Fuel Blend. Amyris direct sugar to hydrocarbon (DSHC) fuel (POSF 10370) come from direct fermentation of bio feedstock sugar. Amyris DSHC is mainly composed of 2,6,10-trymethly dodecane, or farnesane. Gevo jet blend stock fuel is alcohol to jet (ATJ) fuel (POSF 10262) produced from bio derived butanol. Gevo jet blend stock is composed with iso-dodecane and iso-cetane, and has significantly low derived cetane number of 15. The experimental results are compared to combustion characteristics of conventional jet A fuels, including JP-8. Ignition delay, the important factor of auto ignition characteristic, is evaluated from pressure trace measured from the RCM at University of Illinois, Urbana-Champaign. The measurements are made at compressed pressure 20bar, intermediate and low compressed temperature, and equivalence ratio of unity and below. Direct test chamber charge method is used due to its reliable reproducibility of results. Compared to category A fuels, different combustion characteristics has been observed from category C fuels due to their irregular chemical composition.

Fuel-Sensitive Ignition Delay Models for a Local and Global Description of Direct Injection Internal Combustion Engines

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Kyoung Hyun Kwak ◽  
Claus Borgnakke ◽  
Dohoy Jung
Keyword(s):  
Ignition Delay ◽  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Cetane Number ◽  
Global Model ◽  
Local Model ◽  
Delay Model ◽  
Lower Accuracy ◽  
Delay Models ◽  
Single Calibration

Models for ignition delay are investigated and fuel-specific properties are included to predict the effects of different fuels on the ignition delay. These models follow the Arrhenius type expression for the ignition delay modified with the oxygen concentration and Cetane number to extend the range of validity. In this investigation, two fuel-sensitive spray ignition delay models are developed: a global model and a local model. The global model is based on the global combustion chamber charge properties including temperature, pressure, and oxygen/fuel content. The local model is developed to account for temporal and spatial variations in properties of separated spray zones such as local temperature, oxidizer, and fuel concentrations obtained by a quasi-dimensional multizone fuel spray model. These variations are integrated in time to predict the ignition delay. Often ignition delay models are recalibrated for a specific fuel but in this study, the global ignition delay model includes the Cetane number to capture ignition delay of various fuels. The local model uses Cetane number and local stoichiometric oxygen to fuel molar ratio. The model is therefore capable of predicting spray ignition delays for a set of fuels with a single calibration. Experimental dataset of spray ignition delay in a constant volume chamber is used for model development and calibration. The models show a good accuracy for the predicted ignition delay of four different fuels: JP8, DF2, n-heptane, and n-dodecane. The investigation revealed that the most accurate form of the models is from a calibration done for each individual fuel with only a slight decrease in accuracy when a single calibration is done for all fuels. The single calibration case is the more desirable outcome as it leads to general models that cover all the fuels. Of the two proposed models, the local model has a slightly better accuracy compared to the global model. Results for both models demonstrate the improvements that can be obtained for the ignition delay model when additional fuel-specific properties are included in the spray ignition model. Other alternative fuels like synthetic oxygenated fuels were included in the investigation. These fuels behave differently such that the Cetane number does not provide the same explanation for the trend in ignition delay. Though of lower accuracy, the new models do improve the predictive capability when compared with existing types of ignition delay models applied to this kind of fuels.

Combustion Characteristics of a Dual Fuel Diesel Engine With Natural Gas (Influence of Cetane Number of Ignition Fuel)

2011 ◽  
Author(s):  
Yasufumi Yoshimoto ◽  
Eiji Kinoshita
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Cetane Number ◽  
Engine Performance ◽  
Mean Value ◽  
Combustion Characteristics ◽  
Combustion Stability ◽  
Dual Fuel ◽  
Gas Oil ◽  
Performance And Emission

This paper investigates the performance, exhaust emissions, and combustion characteristics of a dual fuel diesel engine fueled by CNG (compressed natural gas) as the main fuel. The experiments used standard ignition fuels prepared by n-hexadecane and heptamethylnonane which are used to define the ignitability of diesel combustion, and focused on the effects of fuels with better ignitability than ordinary gas oil such as fuels with higher cetane numbers, 70 and 100. Compared with gas oil ignition, a standard ignition fuel with C.N. 100 showed shorter ignition delays, and lower NOx exhaust concentrations, and engine noise. The results also showed that regardless of ignition fuel, misfiring occurred when the CNG supply was above 75%. While the CNG ratio where misfiring occurs lowered somewhat with increasing C.N., the combustion stability (defined as the standard deviation in the cycle to cycle variation of IMEP divided by the mean value of IMEP) was little influenced. In summary, the results show that the influence of the ignitability on the engine performance and emission characteristics of the dual fuel operation is relatively small when the ignition fuel has C.N., and similar to or higher than ordinary gas oil.

scholarly journals An Extensive Analysis of Biodiesel Blend Combustion Characteristics under a Wide-Range of Thermal Conditions of a Cooperative Fuel Research Engine

2020 ◽  
Vol 12 (18) ◽  
pp. 7666
Author(s):  
Vu H. Nguyen ◽  
Minh Q. Duong ◽  
Kien T. Nguyen ◽  
Thin V. Pham ◽  
Phuong X. Pham
Keyword(s):  
Alternative Fuels ◽  
Fossil Fuels ◽  
Fuel Injection ◽  
Cetane Number ◽  
Thermal Conditions ◽  
Combustion Characteristics ◽  
Mixing Rate ◽  
Start Of Injection ◽  
Wide Range ◽  
Physical And Chemical

Examining the influence of thermal conditions in the engine cylinder at the start of fuel injection on engine combustion characteristics is critically important. This may help to understand physical and chemical processes occurring in engine cycles and this is relevant to both fossil fuels and alternative fuels like biodiesels. In this study, six different biodiesel–diesel blends (B0, B10, B20, B40, B60 and B100 representing 0, 10, 20, 40, 60 and 100% by volume of biodiesel in the diesel–biodiesel mixtures, respectively) have been successfully tested in a cooperative fuel research (CFR) engine operating under a wide range of thermal conditions at the start of fuel injection. This is a standard cetane testing CFR-F5 engine, a special tool for fuel research. In this study, it was further retrofitted to investigate combustion characteristics along with standard cetane measurements for those biodiesel blends. The novel biodiesel has been produced from residues taken from a palm cooking oil manufacturing process. It is found that the cetane number of B100 is almost 30% higher than that of B0 and this could be attributed to the oxygen content in the biofuel. Under similar thermal conditions at the start of injection, it is observed that the influence of engine load on premixed combustion is minimal. This could be attributable to the well-controlled intake air temperature in this special engine and therefore the evaporation and mixing rate prior to the start of combustion is similar under different loading conditions. Owing to higher cetane number (CN), B100 is more reactive and auto-ignites up to 3 degrees of crank angle (DCA) earlier compared to B0. It is generally observed in this study that B10 shows a higher maximum value of in-cylinder pressure compared to that of B0 and B20. This could be evidence for lubricant enhancement when operating the engine with low-blending ratio mixtures like B10 in this case.

Investigation on the spray development, the combustion characteristics and the emissions of Fischer–Tropsch fuel and diesel fuel from direct coal liquefaction

2017 ◽  
Vol 231 (13) ◽  
pp. 1829-1837 ◽  
Author(s):  
Yiqiang Pei ◽  
Jing Qin ◽  
Yuli Dai ◽  
Kun Wang
Keyword(s):  
Diesel Fuel ◽  
Ignition Delay ◽  
Cetane Number ◽  
Combustion Process ◽  
Physicochemical Characteristics ◽  
Combustion Characteristics ◽  
Coal Liquefaction ◽  
Fischer Tropsch ◽  
Planar Laser ◽  
Direct Coal Liquefaction

Diesel fuel is largely consumed by transportation services, and diesel fuel from direct coal liquefaction and Fischer–Tropsch fuel have been produced as alternatives in coal-rich areas. However, the physicochemical characteristics of the two fuels are not quite the same as those of diesel fuel derived from crude oil. Therefore, the spray development, the combustion characteristics and the emissions of diesel fuel from direct coal liquefaction, Fischer–Tropsch fuel and commercial diesel fuel were studied in this paper. The spray development was investigated by using planar laser-induced fluorescence, and the results showed that the spray characteristics of coal-liquefied fuel were similar to those of commercial diesel fuel. Diesel fuel from direct coal liquefaction has a longer ignition delay and a higher heat release rate from premixed combustion than commercial diesel fuel does because of its lower cetane number at low loads. However, the same combustion characteristics with commercial diesel fuel can be achieved by mixing diesel fuel from direct coal liquefaction and Fischer–Tropsch fuel in a ratio of 3 to 1. With increasing engine load, the in-cylinder temperature and the pressure increased which reduced the effect of the cetane number on the ignition delay and the combustion process. The regulated emissions from Fischer–Tropsch fuel were the lowest of these fuels; the unregulated emissions measured by Fourier transform infrared spectroscopy, however, were slightly higher than those of the other two fuels.

scholarly journals Relationship between Fuel Properties and Cetane Response of Cetane Improver for Non-Aromatic and Aromatic Fuels Used In A Single Cylinder Heavy Duty Diesel Engine

2019 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Sensitivity Analysis ◽  
Diesel Engine ◽  
Ignition Delay ◽  
Cetane Number ◽  
Fuel Properties ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Ignition Quality ◽  
Main Factors ◽  
Heavy Duty Diesel

Ignition improver additives are used to improve the ignition quality, or reduce the ignition delay; i.e. the time between when fuel is injected and time when combustion start is different this difference in time is minimize by additive is called cetane improver (CN). The Cetane Number (CN) is the most widely accepted measure of ignition quality to get desired value of centane number some additive are used hence ignition improvers are usually characterized by the fact that at what extent they can increase CN. By increasing cetane number we have two benefits that it helps smoother combustion and lower emissions. Fuel properties are always considered as one of the main factors to diesel engines concerning performance of cetane improver. There are still challenges for researchers to identify the most correlating and non-correlating fuel properties and their effects on cetane improver .In this study to derive the most un-correlating and correlating properties. In parallel, sensitivity analysis was performed for the fuel properties as well as to effect on performance of cetane improver

scholarly journals Experimental Study of the Effect of Intake Oxygen Concentration on Engine Combustion Process and Hydrocarbon Emissions with N-Butanol-Diesel Blended Fuel

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1310 ◽  
Author(s):  
Wei Tian ◽  
Yunlu Chu ◽  
Zhiqiang Han ◽  
Xiang Wang ◽  
Wenbin Yu ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Ignition Delay ◽  
Cetane Number ◽  
Combustion Process ◽  
Delay Period ◽  
Blended Fuel ◽  
The Difference ◽  
Hc Emissions ◽  
Oxygen Medium ◽  
Ignition Delay Period

This paper summarizes a study based on a modified, light, single-cylinder diesel engine and the effects of the physicochemical properties for n-butanol-diesel blended fuel on the combustion process and hydrocarbon (HC) emissions in the intake at a medium speed and moderate load in, an oxygen-rich environment (Coxy = 20.9–16%), an oxygen-medium environment (Coxy = 16–12%), and an oxygen-poor environment (Coxy = 12–9%). The results show that the ignition delay period is the main factor affecting the combustion process and it has a decisive influence on HC emissions. In an oxygen-medium environment, combustion duration affected by the cetane number is the main reason for the difference in HC emissions between neat diesel fuel (B00) and diesel/n-butanol blended fuel (B20), and its influence increases as the intake oxygen concentration decreases. In an oxygen-poor environment, in-cylinder combustion temperature affected by the latent heat of vaporization is the main reason for the difference in HC emissions between B00 and B20 fuels, and its influence increases as the intake oxygen concentration decreases. By comparing B20 fuel with diesel/n-butanol/2-ethylhexyl nitrate blended fuel (B20 + EHN), the difference in the ignition delay period caused by the difference in the cetane number is the main reason for the difference in HC emissions between B20 and B20 + EHN fuels in oxygen-poor environment, and the effect of this influencing factor gradually increases as the intake oxygen concentration decreases.

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