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Eric Sattler - One of the best experts on this subject based on the ideXlab platform.
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Formulation of Sasol Isomerized Paraffinic Kerosene Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester
Journal of Engineering for Gas Turbines and Power, 2017Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Peter Schihl, Eric SattlerAbstract: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.
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Formulation of Sasol IPK Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester (IQT)
ASME 2016 Internal Combustion Engine Division Fall Technical Conference, 2016Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Peter Schihl, Eric SattlerAbstract:This paper presents an approach to develop Sasol IPK (Iso-Paraffinic Kerosene) surrogate fuels for diesel engine application using Ignition Quality Tester (IQT). The methodology includes: 1) in-house developed MATLAB code to formulate the appropriate mixture blends, 2) Aspen HYSYS to develop the distillation curve and compares it to the target Sasol IPK fuel, 3) IQT to measure the derived cetane number (DCN) of surrogate fuels and compare it with the target Sasol IPK fuel, 4) analysis of autoignition and combustion characteristics for Sasol IPK surrogate fuels. The ignition delay, combustion gas pressure, and rate of heat release of Sasol IPK and its formulated surrogate fuel are analyzed and compared at five different charge temperatures. Furthermore, the apparent activation energies derived from chemical ignition delay of the surrogate fuel and Sasol IPK are determined and compared.
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An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion
Journal of Engineering for Gas Turbines and Power, 2015Co-Authors: Umashankar Joshi, Ziliang Zheng, Naeim A. Henein, Amit Shrestha, Eric SattlerAbstract: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 CFR 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 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 ignition delay (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.Copyright © 2014 by ASME
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An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion
Volume 1: Large Bore Engines; Fuels; Advanced Combustion; Emissions Control Systems, 2014Co-Authors: Umashankar Joshi, Ziliang Zheng, Naeim A. Henein, Amit Shrestha, Eric SattlerAbstract: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 CFR 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 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 ignition delay (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.
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Role of Volatility in the Development of JP-8 Surrogates for Diesel Engine Application
SAE International Journal of Fuels and Lubricants, 2014Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Amit Shrestha, Po I. Lee, Ming Chia Lai, Eric SattlerAbstract:Surrogates for JP8 have been developed in the high temperature gas phase environment of gas turbines. In diesel engines, the fuel is introduced in the liquid phase where volatility plays a major role in the formation of the combustible mixture and autoignition reactions that occur at relatively lower temperatures. In this paper, the role of volatility on the combustion of JP8 and five different surrogate fuels was investigated in the constant volume combustion chamber of the Ignition Quality Tester (IQT). IQT is used to determine the derived cetane number (DCN) of diesel engine fuels according to ASTM D6890. The surrogate fuels were formulated such that their DCNs matched that of JP8, but with different volatilities. Tests were conducted to investigate the effect of volatility on the autoignition and combustion characteristics of the surrogates using a detailed analysis of the rate of heat release immediately after the start of injection. In addition, the effect of volatility on the spray dynamics was investigated by Schlieren imaging in an optically accessible rapid compression machine (RCM). The images supported the conclusions made in the IQT tests. Furthermore, apparent activation energies of JP8 and surrogate fuels were determined based on the chemical delay periods, which could be considered as a new parameter for developing surrogate fuel. Sector: Automotive
Naeim A. Henein - One of the best experts on this subject based on the ideXlab platform.
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EXPERIMENTAL VALIDATION OF A 3-COMPONENT SURROGATE FOR SASOL-IPK IN SINGLE CYLINDER DIESEL ENGINE AND IQT
Journal of Engineering for Gas Turbines and Power, 2018Co-Authors: Samy A. Alkhayat, Naeim A. Henein, Manan Trivedi, Sampad Mukhopadhyay, Peter SchihlAbstract: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.
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Formulation of Sasol Isomerized Paraffinic Kerosene Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester
Journal of Engineering for Gas Turbines and Power, 2017Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Peter Schihl, Eric SattlerAbstract: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.
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Formulation of Sasol IPK Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester (IQT)
ASME 2016 Internal Combustion Engine Division Fall Technical Conference, 2016Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Peter Schihl, Eric SattlerAbstract:This paper presents an approach to develop Sasol IPK (Iso-Paraffinic Kerosene) surrogate fuels for diesel engine application using Ignition Quality Tester (IQT). The methodology includes: 1) in-house developed MATLAB code to formulate the appropriate mixture blends, 2) Aspen HYSYS to develop the distillation curve and compares it to the target Sasol IPK fuel, 3) IQT to measure the derived cetane number (DCN) of surrogate fuels and compare it with the target Sasol IPK fuel, 4) analysis of autoignition and combustion characteristics for Sasol IPK surrogate fuels. The ignition delay, combustion gas pressure, and rate of heat release of Sasol IPK and its formulated surrogate fuel are analyzed and compared at five different charge temperatures. Furthermore, the apparent activation energies derived from chemical ignition delay of the surrogate fuel and Sasol IPK are determined and compared.
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An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion
Journal of Engineering for Gas Turbines and Power, 2015Co-Authors: Umashankar Joshi, Ziliang Zheng, Naeim A. Henein, Amit Shrestha, Eric SattlerAbstract: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 CFR 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 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 ignition delay (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.Copyright © 2014 by ASME
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An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion
Volume 1: Large Bore Engines; Fuels; Advanced Combustion; Emissions Control Systems, 2014Co-Authors: Umashankar Joshi, Ziliang Zheng, Naeim A. Henein, Amit Shrestha, Eric SattlerAbstract: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 CFR 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 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 ignition delay (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.
Ziliang Zheng - One of the best experts on this subject based on the ideXlab platform.
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Formulation of Sasol Isomerized Paraffinic Kerosene Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester
Journal of Engineering for Gas Turbines and Power, 2017Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Peter Schihl, Eric SattlerAbstract: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.
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Formulation of Sasol IPK Surrogate Fuel for Diesel Engine Application Using an Ignition Quality Tester (IQT)
ASME 2016 Internal Combustion Engine Division Fall Technical Conference, 2016Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Peter Schihl, Eric SattlerAbstract:This paper presents an approach to develop Sasol IPK (Iso-Paraffinic Kerosene) surrogate fuels for diesel engine application using Ignition Quality Tester (IQT). The methodology includes: 1) in-house developed MATLAB code to formulate the appropriate mixture blends, 2) Aspen HYSYS to develop the distillation curve and compares it to the target Sasol IPK fuel, 3) IQT to measure the derived cetane number (DCN) of surrogate fuels and compare it with the target Sasol IPK fuel, 4) analysis of autoignition and combustion characteristics for Sasol IPK surrogate fuels. The ignition delay, combustion gas pressure, and rate of heat release of Sasol IPK and its formulated surrogate fuel are analyzed and compared at five different charge temperatures. Furthermore, the apparent activation energies derived from chemical ignition delay of the surrogate fuel and Sasol IPK are determined and compared.
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An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion
Journal of Engineering for Gas Turbines and Power, 2015Co-Authors: Umashankar Joshi, Ziliang Zheng, Naeim A. Henein, Amit Shrestha, Eric SattlerAbstract: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 CFR 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 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 ignition delay (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.Copyright © 2014 by ASME
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An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion
Volume 1: Large Bore Engines; Fuels; Advanced Combustion; Emissions Control Systems, 2014Co-Authors: Umashankar Joshi, Ziliang Zheng, Naeim A. Henein, Amit Shrestha, Eric SattlerAbstract: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 CFR 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 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 ignition delay (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.
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Role of Volatility in the Development of JP-8 Surrogates for Diesel Engine Application
SAE International Journal of Fuels and Lubricants, 2014Co-Authors: Ziliang Zheng, Naeim A. Henein, Tamer Badawy, Amit Shrestha, Po I. Lee, Ming Chia Lai, Eric SattlerAbstract:Surrogates for JP8 have been developed in the high temperature gas phase environment of gas turbines. In diesel engines, the fuel is introduced in the liquid phase where volatility plays a major role in the formation of the combustible mixture and autoignition reactions that occur at relatively lower temperatures. In this paper, the role of volatility on the combustion of JP8 and five different surrogate fuels was investigated in the constant volume combustion chamber of the Ignition Quality Tester (IQT). IQT is used to determine the derived cetane number (DCN) of diesel engine fuels according to ASTM D6890. The surrogate fuels were formulated such that their DCNs matched that of JP8, but with different volatilities. Tests were conducted to investigate the effect of volatility on the autoignition and combustion characteristics of the surrogates using a detailed analysis of the rate of heat release immediately after the start of injection. In addition, the effect of volatility on the spray dynamics was investigated by Schlieren imaging in an optically accessible rapid compression machine (RCM). The images supported the conclusions made in the IQT tests. Furthermore, apparent activation energies of JP8 and surrogate fuels were determined based on the chemical delay periods, which could be considered as a new parameter for developing surrogate fuel. Sector: Automotive
Bradley T Zigler - One of the best experts on this subject based on the ideXlab platform.
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Comparing Cetane Number Measurement Methods
ASME 2020 Internal Combustion Engine Division Fall Technical Conference, 2020Co-Authors: Riley C. Abel, Matthew A Ratcliff, Jon Luecke, Bradley T ZiglerAbstract:Abstract Cetane number is one of the most important fuel performance metrics for mixing controlled compression-ignition “diesel” engines, quantifying a fuel’s propensity for autoignition when injected into end-of-compression-type temperature and pressure conditions. The historical default and referee method on a Cooperative Fuel Research (CFR) engine configured with indirect fuel injection and variable compression ratio is cetane number (CN) rating. A subject fuel is evaluated against primary reference fuel blends, with heptamethylnonane defining a low-reactivity endpoint of CN = 15 and hexadecane defining a high-reactivity endpoint of CN = 100. While the CN scale covers the range from zero (0) to 100, typical testing is in the range of 30 to 65 CN. Alternatively, several constant-volume combustion chamber (CVCC)-based cetane rating devices have been developed to rate fuels with an equivalent derived cetane number (DCN) or indicated cetane number (ICN). These devices measure ignition delay for fuel injected into a fixed volume of high-temperature and high-pressure air to simulate end-of-compression-type conditions. In this study, a range of novel fuel compounds are evaluated across three CVCC methods: the Ignition Quality Tester (IQT), Fuel Ignition Tester (FIT), and Advanced Fuel Ignition Delay Analyzer (AFIDA). Resulting DCNs and ICNs are compared for fuels within the normal diesel fuel range of reactivity, as well as very high (∼100) and very low DCNs/ICNs (∼5). Distinct differences between results from various devices are discussed. This is important to consider because some new, high-efficiency advanced compression-ignition (CI) engine combustion strategies operate with more kinetically controlled distributed combustion as opposed to mixing controlled diffusion flames. These advanced combustion strategies may benefit from new fuel chemistries, but current rating methods of CN, DCN, and ICN may not fully describe their performance. In addition, recent evidence suggests ignition delay in modern on-road diesel engines with high-pressure common rail fuel injection systems may no longer directly correlate to traditional CN fuel ratings. Simulated end-of-compression conditions are compared for CN, DCN, and ICN and discussed in the context of modern diesel engines to provide additional insight. Results highlight the potential need for revised and/or multiple fuel test conditions to measure fuel performance for advanced CI strategies.
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The impact of physicochemical property interactions of iso-octane/ethanol blends on ignition timescales
Fuel, 2018Co-Authors: Cesar L. Barraza-botet, Jon Luecke, Bradley T Zigler, Margaret S. WooldridgeAbstract:Abstract This work presents new measurements of liquid fuel ignition delay times of iso -octane and ethanol fuel blends obtained from an ignition Quality Tester at the National Renewable Energy Laboratory (NREL IQT), which are compared to previous ignition delay data from the University of Michigan rapid compression facility (UM RCF), at the same experimental conditions. Pressure-time histories were used to determine liquid fuel ignition delays at global stoichiometric non-premixed conditions for iso -octane, ethanol and iso -octane/ethanol blends of 25, 50, 75% by volume in mixtures of 10% oxygen diluted in nitrogen. Temperatures ranging from 880 to 970 K were studied at a pressure of 10 atm. By comparing total ignition delay times from the NREL IQT with chemical ignition delay times from the UM RCF, the contributions of physical phenomena were quantified as representative time scales for spray injection, breakup and evaporation processes, and for gas-phase turbulent mixing. Regression analyses were developed for ignition time scales as function of blend level and charge temperature. Non-dimensional analyses were also carried out to determine the relative effects of physical time scales with respect to chemical ignition delay times.
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effects of iso octane ethanol blend ratios on the observance of negative temperature coefficient behavior within the ignition Quality Tester
Fuel, 2016Co-Authors: Gregory E Bogin, Eric Osecky, Matthew A Ratcliff, Jon Luecke, Bradley T ZiglerAbstract:Abstract An ignition delay study investigating the reduction in low temperature heat release (LTHR) and negative temperature coefficient (NTC) region with increasing ethanol concentration in binary blends of ethanol/isooctane was conducted in the Ignition Quality Tester (IQT). The IQT is advantageous for studying multi-component fuels such as iso -octane/ethanol which are difficult to study at lower temperatures covering the NTC region in traditional systems (e.g., shock tubes, rapid compression machines, etc.). The high octane numbers and concomitant long ignition delay times of ethanol and iso -octane are ideal for study in the IQT allowing the system to reach a quasi-homogeneous mixture; allowing the effect of fuel chemistry on ignition delay to be investigated with minimal impact from the fuel spray due to the relatively long ignition times. NTC behavior from iso -octane/ethanol blends was observed for the first time using an IQT. Temperature sweeps of iso -octane/ethanol volumetric blends (100/0, 90/10, 80/20, 50/50, and 0/100) were conducted from 623 to 993 K at 0.5, 1.0 and 1.5 MPa and global equivalence ratios ranging from 0.7 to 1.0. Ignition of the iso -octane/ethanol blends in the IQT was also modeled using a 0-D homogeneous batch reactor model. Significant observations include: (1) NTC behavior was observed for ethanol/ iso -octane fuel blends up to 20% ethanol. (2) Ethanol produced shorter ignition delay times than iso -octane in the high temperature region. (3) The initial increase in ethanol from 0% to 10% had a lesser impact on ignition delay than increasing ethanol from 10% to 20%. (4) The 0-D model predicts that at 0.5 and 1.0 MPa ethanol produces the shortest ignition time in the high-temperature regime, as seen experimentally.
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Investigation of Iso-octane Ignition and Validation of a Multizone Modeling Method in an Ignition Quality Tester
Energy & Fuels, 2016Co-Authors: Eric Osecky, Gregory E Bogin, Matthew A Ratcliff, Jon Luecke, Bradley T Zigler, Stephanie M. Villano, Anthony M DeanAbstract:An ignition Quality Tester was used to characterize the autoignition delay times of iso-octane. The experimental data were characterized between temperatures of 653 and 996 K, pressures of 1.0 and 1.5 MPa, and global equivalence ratios of 0.7 and 1.05. A clear negative temperature coefficient behavior was seen at both pressures in the experimental data. These data were used to characterize the effectiveness of three modeling methods: a single-zone homogeneous batch reactor, a multizone engine model, and a three-dimensional computational fluid dynamics (CFD) model. A detailed 874 species iso-octane ignition mechanism (Mehl, M.; Curran, H. J.; Pitz, W. J.; Westbrook, C. K. Chemical kinetic modeling of component mixtures relevant to gasoline. Proceedings of the European Combustion Meeting; Vienna, Austria, April 14–17, 2009) was reduced to 89 species for use in these models, and the predictions of the reduced mechanism were consistent with ignition delay times predicted by the detailed chemical mechanism acr...
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Effects of iso-octane/ethanol blend ratios on the observance of negative temperature coefficient behavior within the Ignition Quality Tester
Fuel, 2016Co-Authors: Gregory E Bogin, Eric Osecky, Matthew A Ratcliff, Jon Luecke, Bradley T ZiglerAbstract:Abstract An ignition delay study investigating the reduction in low temperature heat release (LTHR) and negative temperature coefficient (NTC) region with increasing ethanol concentration in binary blends of ethanol/isooctane was conducted in the Ignition Quality Tester (IQT). The IQT is advantageous for studying multi-component fuels such as iso -octane/ethanol which are difficult to study at lower temperatures covering the NTC region in traditional systems (e.g., shock tubes, rapid compression machines, etc.). The high octane numbers and concomitant long ignition delay times of ethanol and iso -octane are ideal for study in the IQT allowing the system to reach a quasi-homogeneous mixture; allowing the effect of fuel chemistry on ignition delay to be investigated with minimal impact from the fuel spray due to the relatively long ignition times. NTC behavior from iso -octane/ethanol blends was observed for the first time using an IQT. Temperature sweeps of iso -octane/ethanol volumetric blends (100/0, 90/10, 80/20, 50/50, and 0/100) were conducted from 623 to 993 K at 0.5, 1.0 and 1.5 MPa and global equivalence ratios ranging from 0.7 to 1.0. Ignition of the iso -octane/ethanol blends in the IQT was also modeled using a 0-D homogeneous batch reactor model. Significant observations include: (1) NTC behavior was observed for ethanol/ iso -octane fuel blends up to 20% ethanol. (2) Ethanol produced shorter ignition delay times than iso -octane in the high temperature region. (3) The initial increase in ethanol from 0% to 10% had a lesser impact on ignition delay than increasing ethanol from 10% to 20%. (4) The 0-D model predicts that at 0.5 and 1.0 MPa ethanol produces the shortest ignition time in the high-temperature regime, as seen experimentally.
S. Mani Sarathy - One of the best experts on this subject based on the ideXlab platform.
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Ethanolic gasoline, a lignocellulosic advanced biofuel
Sustainable Energy & Fuels, 2019Co-Authors: Mícheál Séamus Howard, Nimal Naser, S. Mani Sarathy, Gani Issayev, Aamir Farooq, Stephen DooleyAbstract:In line with society's growing need for a more sustainable fuel economy, various biofuels and alternative fuel formulations are being proposed. In this work, the ignition Quality of a novel tricomponent advanced biofuel is examined. Ethyl levulinate, diethyl ether and ethanol (EL/DEE/EtOH) result from the acid hydrolysis of lignocellulosic biomass in ethanol. In this paper, derived cetane numbers are established for a wide variety of blend fractions, using Ignition Quality Tester measurements. EL/DEE/EtOH mixtures of ignition Quality equivalent to market diesel and gasoline are identified. One mixture of Motor Octane Number (MON) 88.3 and Research Octane Number (RON) 95 is selected for detailed analysis in comparison to a FACE (Fuels for Advanced Combustion Engines) gasoline, as a representative of petroleum-derived gasoline, with a similar MON of 88.8 and RON of 94.4. Ignition delay times for the EL/DEE/EtOH gasoline fuel are measured using a rapid compression machine at equivalence ratios of 0.5 and 1.0, at 20 and 40 bar over a temperature range of 600–900 K. The data shows that at temperatures >800 K, the EL/DEE/EtOH fuel behaves quite similar to the petroleum derived gasoline, FACE-F. However, the tri-component biofuel shows a dramatically truncated extent of ignition reactivity at lower temperatures, with a total absence of low-temperature chemistry or negative temperature coefficient (NTC) region; in this respect this biofuel blend is very different to conventional gasoline. To understand this differing behaviour, a detailed chemical kinetic model is developed. Analysis of this model shows that ignition of the EL/DEE/EtOH blend is inhibited by the dominance of alkyl radical elimination pathways, which leads to a heightened rate of production of HO2 radicals. At high temperatures, while both fuels maintain a similar ignition delay time, the sensitivity analysis and the radical pool population shows that a different combustion mechanism is occurring for the EL/DEE/EtOH fuel, where ethyl and methyl radicals play a much more prominent role in the ignition process.
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The influence of chemical composition on ignition delay times of gasoline fractions
Combustion and Flame, 2019Co-Authors: Nimal Naser, Suk Ho Chung, Eshan Singh, Abdul Gani Abdul Jameel, Abdul-hamid M. Emwas, S. Mani SarathyAbstract:Abstract Tailoring fuel properties to maximize the efficiency of internal combustion engines is a way towards achieving cleaner combustion systems. In this work, the ignition properties along with the chemical composition (expressed as functional groups) of various light distillate (e.g., gasoline) cuts were analyzed to better understand the properties of full boiling range fuels. Various distillation cuts were obtained with a spinning band distillation system, which were then tested in an ignition Quality Tester (IQT) to obtain their global chemical reactivity (i.e., ignition delay time (IDT)). The distillates were further analyzed with 1H nuclear magnetic resonance (NMR) spectroscopy to identify and quantify various functional groups present in them. Various gasolines of research grade with specific target properties set forth by the Coordinating Research Council (CRC) that are known as FACE (fuels for advanced combustion engines) gasolines were distilled. When fuels with low aromatic content were distilled, the higher boiling point (BP) range (i.e., higher molecular weight) fractions exhibited lower IDT. However, distilled fractions of fuels with high aromatic content showed an initial decrease in IDT with increasing BP, followed by drastic increase in IDT primarily due to increasing aromatic groups. This study provides an understanding of the contribution of various volatile fractions to the IDTs of a multicomponent fuel, which is of relevance to fuel stratification utilized in gasoline compression ignition (GCI) engines to tailor heat release rates.
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Ignition delay time sensitivity in ignition Quality Tester (IQT) and its relation to octane sensitivity
Fuel, 2018Co-Authors: Nimal Naser, S. Mani Sarathy, Suk Ho ChungAbstract:Abstract Cetane number (CN) is a commonly used metric to rate the ignition Quality of distillate fuels. In this work, a concept of sensitivity in ignition delay time (IDT) obtained with an ignition Quality Tester (IQT) is proposed, which is correlated to octane sensitivity (OS), i.e., the difference between research octane number (RON) and motor octane number (MON). The concept is based on the determination of IDT using the ASTM D6890 standard and IDT obtained at a temperature lower than that prescribed by the standard. The IDT measured at this lower temperature is referred to as IDT l , which is obtained via a calibration procedure similar to the ASTM D6890 standard, but with a higher value of reference IDT for calibration with n-heptane. The IDT h (measured at the derived cetane number (DCN) ASTM D6890 condition) of a given test fuel and a binary primary reference fuel (PRF) mixture of iso-octane and n-heptane was measured to identify a PRF with matching IDTh as the test fuel. The ratio of low temperature IDTs of the non-PRF test fuel and PRF, i.e., IDT l , non-PRF / IDT l , PRF was defined as IDT sensitivity (IDS), which was correlated with the OS of the test fuel. The RON and MON values of a wide range of fuel classes including surrogate fuels and fully blended practical fuels were estimated, and showed satisfactory agreement with measured RON/MON values. The RON values of many pure components that could not be measured with the standard test method ASTM D2699 were also estimated. Two certification diesels and Saudi Arabian pump grade diesel were also tested.
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A minimalist functional group (MFG) approach for surrogate fuel formulation
Combustion and Flame, 2018Co-Authors: Abdul Gani Abdul Jameel, Nimal Naser, Stephen Dooley, Gani Issayev, Aamir Farooq, Abdul-hamid M. Emwas, Manik Kumer Ghosh, Jamal Touitou, S. Mani SarathyAbstract:Abstract Surrogate fuel formulation has drawn significant interest due to its relevance towards understanding combustion properties of complex fuel mixtures. In this work, we present a novel approach for surrogate fuel formulation by matching target fuel functional groups, while minimizing the number of surrogate species. Five key functional groups; paraffinic CH3, paraffinic CH2, paraffinic CH, naphthenic CH CH2 and aromatic C CH groups in addition to structural information provided by the Branching Index (BI) were chosen as matching targets. Surrogates were developed for six FACE (Fuels for Advanced Combustion Engines) gasoline target fuels, namely FACE A, C, F, G, I and J. The five functional groups present in the fuels were qualitatively and quantitatively identified using high resolution 1H Nuclear Magnetic Resonance (NMR) spectroscopy. A further constraint was imposed in limiting the number of surrogate components to a maximum of two. This simplifies the process of surrogate formulation, facilitates surrogate testing, and significantly reduces the size and time involved in developing chemical kinetic models by reducing the number of thermochemical and kinetic parameters requiring estimation. Fewer species also reduces the computational expenses involved in simulating combustion in practical devices. The proposed surrogate formulation methodology is denoted as the Minimalist Functional Group (MFG) approach. The MFG surrogates were experimentally tested against their target fuels using Ignition Delay Times (IDT) measured in an Ignition Quality Tester (IQT), as specified by the standard ASTM D6890 methodology, and in a Rapid Compression Machine (RCM). Threshold Sooting Index (TSI) and Smoke Point (SP) measurements were also performed to determine the sooting propensities of the surrogates and target fuels. The results showed that MFG surrogates were able to reproduce the aforementioned combustion properties of the target FACE gasolines across a wide range of conditions. The present MFG approach supports existing literature demonstrating that key functional groups are responsible for the occurrence of complex combustion properties. The functional group approach offers a method of understanding the combustion properties of complex mixtures in a manner which is independent, yet complementary, to detailed chemical kinetic models. The MFG approach may be readily extended to formulate surrogates for other complex fuels.
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2-Methylfuran: A bio-derived octane booster for spark-ignition engines
Fuel, 2018Co-Authors: Eshan Singh, Heinz Pitsch, Vijai Shankar Bhavani Shankar, Rupali Tripathi, S. Mani SarathyAbstract:Abstract The efficiency of spark-ignition engines is limited by the phenomenon of knock, which is caused by auto-ignition of the fuel-air mixture ahead of the spark-initiated flame front. The resistance of a fuel to knock is quantified by its octane index; therefore, increasing the octane index of a spark-ignition engine fuel increases the efficiency of the respective engine. However, raising the octane index of gasoline increases the refining costs, as well as the energy consumption during production. The use of alternative fuels with synergistic blending effects presents an attractive option for improving octane index. In this work, the octane enhancing potential of 2-methylfuran (2-MF), a next-generation biofuel, has been examined and compared to other high-octane components (i.e., ethanol and toluene). A primary reference fuel with an octane index of 60 (PRF60) was chosen as the base fuel since it closely represents refinery naphtha streams, which are used as gasoline blend stocks. Initial screening of the fuels was done in an ignition Quality Tester (IQT). The PRF60/2-MF (80/20 v/v%) blend exhibited longer ignition delay times compared to PRF60/ethanol (80/20 v/v%) blend and PRF60/toluene (80/20 v/v%) blend, even though pure 2-MF is more reactive than both ethanol and toluene. The mixtures were also tested in a cooperative fuels research (CFR) engine under research octane number and motor octane number like conditions. The PRF60/2-MF blend again possesses a higher octane index than other blending components. A detailed chemical kinetic analysis was performed to understand the synergetic blending effect of 2-MF, using a well-validated PRF/2-MF kinetic model. Kinetic analysis revealed superior suppression of low-temperature chemistry with the addition of 2-MF. The results from simulations were further confirmed by homogeneous charge compression ignition engine experiments, which established its superior low-temperature heat release (LTHR) suppression compared to ethanol, resulting in better blending octane numbers. This work explores and provides a chemically sound explanation for the potential of 2-MF as an octane enhancer.
