A Proposed Biodiesel Combustion Kinetics Based on the Computational Fluid Dynamics Results in an Ignition Quality Tester

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Mahmoud Elhalwagy ◽  
Chao Zhang
Keyword(s):  
Methyl Ester ◽  
Ignition Delay ◽  
Methyl Esters ◽  
Direct Injection ◽  
Combustion Process ◽  
Major Fatty Acid ◽  
Combustion Behavior ◽  
Ignition Quality ◽  
Reaction Constants ◽  
Ignition Quality Tester

In this paper, five biodiesel global combustion decomposition steps are added to a surrogate mechanism to accurately represent the chemical kinetics of the decomposition of different levels of saturation of biodiesel, which are represented by five major fatty acid methyl esters. The reaction constants were tuned based on the results from the numerical simulations of the combustion process in an ignition quality tester (IQT) in order to obtain accurate cetane numbers. The prediction of the complete thermophysical properties of the five constituents is also carried out to accurately represent the physics of the spray and vaporization processes. The results indicated that the combustion behavior is controlled more by the spray and breakup processes for saturated biodiesel constituents than by the chemical delay, which is similar to the diesel fuel combustion behavior. The chemical delay and low temperature reactions were observed to have greater effects on the combustion and ignition delay for the cases of the unsaturated biodiesels. The comparison between the physical ignition delay and overall ignition delay between the saturated and unsaturated biodiesel constituents has also confirmed those stronger effects for the physical delay in the saturated compounds as compared to the unsaturated compounds. The validation of the proposed model is conducted for the simulations of two direct injection diesel engines using palm methyl ester and rape methyl ester.

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.

Combustion Characteristics of Biodiesel Derived from Palm and Rapeseed Oil

2013 ◽  
Vol 448-453 ◽  
pp. 1633-1636
Author(s):  
Xiu Chen ◽  
Lei Chen ◽  
Yin Nan Yuan ◽  
Yong Bin Lai ◽  
Xing Qiao ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Chemical Composition ◽  
Methyl Ester ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Combustion Process ◽  
Acid Methyl Ester ◽  
Combustion Characteristics ◽  
Combustion Characteristic ◽  
Acid Methyl

The chemical composition of palm and rapeseed biodiesel (fatty acid methyl ester, FAME) was analyzed by gas chromatography-mass spectrometry. Combustion characteristics of biodiesel were studied by thermogravimetry-differential scanning calorimetry and collision theory. Combustion characteristic index C was put forward for describing biodiesel combustion characteristic. The reactive atom combustion mechanism was put forward. Biodiesel combustion process comprised three steps, viz., volatilizing, dissociating and combining. First, biodiesel volatilizes, viz., FAME (liquid) volatilize and became FAME (gas). Second, FAME, O2 and N2 molecular were dissociated into C*, H*, O* and N* reactive atoms. Third, C*, H* and N* reacted, respectively, with O* to CO2, CO, H2O and NOx, and released energy. The study showed that the biodiesel was mainly composed of FAME: C14:0-C24:0, C16:1-C22:1, C18:2 and C18:3. Biodiesel had a good burnability. Combustion characteristic indexes of palm methyl ester (PME) and rapeseed methyl ester (RME) were 4.97E-05 and 3.65E-05, respectively. The combustion characteristic had relation to chemical composition. The combustion characteristic of biodiesel was better with increasing saturated fatty acid methyl esters and length of carbon-chain, and was poorer with increasing unsaturated fatty acid methyl esters and unsaturated degree. The combustion characteristic of PME was better than that of RME.

The Shock Tube Autoignition of Biodiesels and Biodiesel Components

2013 ◽  
Author(s):  
Weijing Wang ◽  
Matthew A. Oehlschlaeger
Keyword(s):  
High Temperature ◽  
Methyl Ester ◽  
Shock Tube ◽  
Ignition Delay ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Oh Radicals ◽  
Reflected Shock ◽  
Ignition Delay Times ◽  
Delay Times

The autoignition of fatty-acid methyl ester biodiesels and methyl ester biodiesel components was studied in gas-phase shock tube experiments. Ignition delay times for two reference methyl ester biodiesel fuels, derived from methanol-based transesterification of soybean oil and animal fats, and four primary constituents of all methyl ester biodiesels, methyl palmitate, methyl stearate, methyl oleate, and methyl linoleate, were measured behind reflected shock waves for fuel/air mixtures at temperatures ranging from 900 to 1350 K and at pressures around 10 and 20 atm. Ignition delay times were determined by monitoring pressure and chemiluminescence from electronically-excited OH radicals around 310 nm. The results show similarity in ignition delay times for all methyl ester fuels considered, irrespective of the variations in organic structure, at the high-temperature conditions studied and also similarity in high-temperature ignition delay times for methyl esters and n-alkanes.

Investigation of Papaya Seed Methyl Ester Blended Diesel for Emission Reduction in Direct Injection Engines

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
J. Hemanandh ◽  
S. Ganesan ◽  
A. Shaik Fiaz ◽  
P. Gunasekar
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Emission Reduction ◽  
Seed Oil ◽  
Methyl Esters ◽  
Direct Injection ◽  
Direct Injection Engines ◽  
Full Load ◽  
Toxic Gases ◽  
Papaya Seed

The diesel engines are emitting toxic gases which affect the greenhouse gases. In this research, the methyl esters were extracted from waste papaya seed oil using transesterification process. The Direct Injection Kirloskar diesel engine at constant speed of 1500 rpm and compression ratio of 17.5:1 was used to test the fuel. The injection nozzle holes were varied from 3 to 4 holes. The emissions were recorded using AVL gas analyser. The 20% blend with 4-hole nozzle shows reduction in NOx, CO and CO2 emissions at full load. The performance is increased for 30% blend at full load.

An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Umashankar Joshi ◽  
Ziliang Zheng ◽  
Amit Shrestha ◽  
Naeim Henein ◽  
Eric Sattler
Keyword(s):  
Activation Energy ◽  
Ignition Delay ◽  
Cetane Number ◽  
Ignition Process ◽  
Start Of Injection ◽  
Auto Ignition ◽  
Time Period ◽  
Ignition Quality ◽  
Ignition Quality Tester ◽  
Start Of Combustion

The auto-ignition process plays a major role in the combustion, performance, fuel economy, and emission in diesel engines. The auto-ignition quality of different fuels has been rated by its cetane number (CN) determined in the cooperative fuel research engine, according to ASTM D613. More recently, the ignition quality tester (IQT), a constant volume vessel, has been used to determine the derived cetane number (DCN) to avoid the elaborate, time consuming, and costly engine tests, according to ASTM D6890. The ignition delay (ID) period in these two standard tests and many investigations has been considered to be the time period between start of injection (SOI) and start of combustion (SOC). The ID values determined in different investigations can vary due to differences in instrumentation and definitions. This paper examines the different definitions and the parameters that effect ID period. In addition, the activation energy dependence on the ID definition is investigated. Furthermore, results of an experimental investigation in a single-cylinder research diesel engine will be presented, while the charge density is kept constant during the ID period. The global activation energy is determined and its sensitivity to the charge temperature is examined.

Experimental Validation of a Three-Component Surrogate for Sasol-Isoparaffinic Kerosene in Single Cylinder Diesel Engine and Ignition Quality Tester

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Samy Alkhayat ◽  
Manan Trivedi ◽  
Naeim Henein ◽  
Sampad Mukhopadhyay ◽  
Peter Schihl
Keyword(s):  
Diesel Engine ◽  
Experimental Validation ◽  
Cetane Number ◽  
Negative Temperature ◽  
Single Cylinder ◽  
Combustion Behavior ◽  
Auto Ignition ◽  
Temperature Combustion ◽  
Ignition Quality ◽  
Ignition Quality Tester

Surrogates development is important to extensively investigate the combustion behavior of fuels. Development of comprehensive surrogates has been focusing on matching chemical and physical properties of their target fuel to mimic its atomization, evaporation, mixing, and auto-ignition behavior. More focus has been given to matching the derived cetane number (DCN) as a measure of the auto-ignition quality. In this investigation, we carried out experimental validation of a three-component surrogate for Sasol-Isoparaffinic Kerosene (IPK) in ignition quality tester (IQT) and in an actual diesel engine. The surrogate fuel is composed of three components (46% iso-cetane, 44% decalin, and 10% n-nonane on a volume basis). The IQT experiments were conducted as per ASTM D6890-10a. The engine experiments were conducted at 1500 rpm, two engine loads, and two injection timings. Analysis of ignition delay (ID), peak pressure, peak rate of heat release (RHR), and other combustion phasing parameters showed a closer match in the IQT than in the diesel engine. Comparison between the surrogate combustion behavior in the diesel engine and IQT revealed that matching the DCN of the surrogate to its respective target fuel did not result in the same negative temperature coefficient (NTC) profile—which led to unmatched combustion characteristics in the high temperature combustion (HTC) regimes, despite the same auto-ignition and low temperature combustion (LTC) profiles. Moreover, a comparison between the combustion behaviors of the two fuels in the IQT is not consistent with the comparison in the diesel engine, which suggests that the surrogate validation in a single-cylinder diesel engine should be part of the surrogate development methodology, particularly for low ignition quality fuels.

scholarly journals Combustion and emission characteristics of diesel engine fuelled with rice bran oil methyl ester and its diesel blends

2008 ◽  
Vol 12 (1) ◽  
pp. 139-150 ◽  
Author(s):  
Rao Gattamaneni ◽  
Saravanan Subramani ◽  
Sampath Santhanam ◽  
Rajagopal Kuderu
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Heat Release ◽  
Vegetable Oils ◽  
Rice Bran ◽  
Ignition Delay ◽  
Rice Bran Oil ◽  
Direct Injection ◽  
Engine Fuel ◽  
Maximum Heat

There has been a worldwide interest in searching for alternatives to petroleum-derived fuels due to their depletion as well as due to the concern for the environment. Vegetable oils have capability to solve this problem because they are renewable and lead to reduction in environmental pollution. The direct use of vegetable oils as a diesel engine fuel is possible but not preferable because of their extremely higher viscosity, strong tendency to polymerize and bad cold start properties. On the other hand, Biodiesels, which are derived from vegetable oils, have been recently recognized as a potential alternative to diesel oil. This study deals with the analysis of rice bran oil methyl ester (RBME) as a diesel fuel. RBME is derived through the transesterification process, in which the rice bran oil reacts with methanol in the presence of KOH. The properties of RBME thus obtained are comparable with ASTM biodiesel standards. Tests are conducted on a 4.4 kW, single-cylinder, naturally aspirated, direct-injection air-cooled stationary diesel engine to evaluate the feasibility of RBME and its diesel blends as alternate fuels. The ignition delay and peak heat release for RBME and its diesel blends are found to be lower than that of diesel and the ignition delay decreases with increase in RBME in the blend. Maximum heat release is found to occur earlier for RBME and its diesel blends than diesel. As the amount of RBME in the blend increases the HC, CO, and soot concentrations in the exhaust decreased when compared to mineral diesel. The NOx emissions of the RBME and its diesel blends are noted to be slightly higher than that of diesel.

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