Moaz Al-lehaibi - Profile on Academia.edu (original) (raw)
Papers by Moaz Al-lehaibi
Impact Analysis of the Key Engine Parameters on Piston Lubrication and Friction Performance in Diesel Engines Using GT-SUITE Program
Mechanika, Jun 28, 2024
The Effect of Adding Hybrid Nanoparticles (Al2O3-TiO2) on the Performance of Parabolic Trough Solar Collectors Using Different Thermal Oils and Molten Salts
Case studies in thermal engineering, May 1, 2024
Research Square (Research Square), Apr 15, 2024
There have been continuing efforts in the Engine Combustion Network (ECN) community to understand... more There have been continuing efforts in the Engine Combustion Network (ECN) community to understand the detailed spray characteristics by investigating several standard diesel injectors. With the increasing interest in the use of alternative and renewable fuels, the present study conducted large eddy simulations with dynamic structure subgrid closure in the Eulerian volume-of-fluid (VOF) framework to identify the characteristics of oxymethylene ethers (OME), which has distinct physical and chemical properties leading to low soot emissions. In particular, the spray features of n-dodecane and OME3 were compared and analyzed in terms of their transient dynamics following the nozzle opening. ECN Spray A, C, and D were considered to assess the effects of nozzle convergence factor and nozzle diameter. The measured nozzle geometries by the Argonne National Laboratory were adopted to mimic the internal flow development. Due to the higher density of OME3, it generates a higher projected density, but a lower injection velocity is obtained. This behavior is attributed to its higher mass inertia. The diverging Spray C injector induces a significantly lower projected density and mass flow rate than the converging Spray D injector owing to cavitation just after the sharp nozzle inlet corner. By comparison, the Spray A injector generates the lowest projected density and mass flow rate for its smallest nozzle diameter. Various fuels demonstrate similar flow fields, evidenced by the significantly similar pressure distribution. The OME3 cases lead to a slightly higher temperature distribution within the nozzle channel, which is attributed to the lower turbulent kinetic energy and thus the slower heat transfer process.
Enhancing Thermal Efficiency of Passive Solar Heating Systems Through Copper-Chip Integration: Experimental Investigation and Analysis
Land Fill Gas (LFG) and Biogas are mixtures of methane (CH4) / carbon dioxide (CO2) that can be u... more Land Fill Gas (LFG) and Biogas are mixtures of methane (CH4) / carbon dioxide (CO2) that can be used as energy source in combustors. The presence of CO2 reduces the energy content per unit mass of these gases and negatively impacts the combustion stability. Laminar burning speeds of simulated LFG have been measured in this study. The experiments were conducted in a constant volume cylindrical chamber with the aid of a Z-shaped Schlieren/shadowgraph system. Pressure rise data during the flame propagation were recorded through pressure transducer on the cylindrical chamber wall and were the main input into the thermodynamic model used to measure the laminar burning speed. A high-speed CMOS camera capable of taking pictures up to 40,000 frames per second was used to determine the cellularity of the flame. Pictures of the CH4/air/ CO2 flames for different equivalence ratios and carbon dioxide percentages were taken. As the CO2 mole fraction increased the flame is less prone to become cellular. Fuel rich mixtures are less likely to become cellular than fuel lean mixtures. Experiments of CH4/air/ CO2 mixtures have been conducted to simulate LFG/Biogas and laminar burning speeds were measured. The testing sets included three CO2 mole fractions Xco2= 0%, 20%, and 30% at two initial pressures Pi= 1 atm and 2 atm. Moreover, the set covered three initial temperatures Ti =298 K, 330 K, and 360 K and three fuel air equivalence ratios of ϕ = 0.8,1.0, and 1.2. iii The effect of CO2 on laminar burning speed was determined. As the CO2 mole fraction increased from 0 to 30% the laminar burning speeds decreased. Moreover, data show that the laminar burning speed of CH4/air/ CO2 mixtures reduces with increasing pressure and increases with increasing temperature. The results show, the lowest laminar burning speed was measured at Pi = 2 atm, Ti = 298 K, ϕ = 0.8, and Xco2= 30%. iv ACKNOWKEDGMENT I would like to express my appreciation to Professor Hameed Metghalchi for his support and guidance during the learning journey at the combustion laboratory in Northeastern University. Moreover, I would like to extend my appreciation to the laboratory technician Kevin McCue and to my teammates Kevin Vien, Ziyu Wang, Guangying Yu, and Mohammed Alswat for their corporation and effort during the research process. My parents provided the love and the support that is crucial for me to keep pursuing knowledge and dream big. My wife, Nada Alsaeidi, kept encouraging me to keep a good balance between knowledge and my social life. My sweetest daughter, Lana, kept the smile on my face with her jokes. To my future me, never stop pursuing knowledge. Be wiser. Be smarter. Be happier. v
Fuel, 2017
Gas to liquid (GTL) fuel, synthesized from natural gas through Fisher-Tropsch (F-T) process, has ... more Gas to liquid (GTL) fuel, synthesized from natural gas through Fisher-Tropsch (F-T) process, has gained significant attention due to its cleaner combustion characteristics when compared to conventional fuels. Combustion properties such as flame structure and laminar burning speed of GTL/air mixture premixed flames have been investigated. The GTL fuel used in this research was provided by Air Force Research Laboratory (AFRL), designated by Syntroleum S-8, which was derived from natural gas via F-T process. A mixture of 32% iso-octane, 25% n-decane, and 43% n-dodecane by volume is considered as the surrogates of GTL fuel for filling process. Experiments were conducted using a cylindrical chamber to study the flame structure and a spherical chamber for laminar burning speeds measurement. The cylindrical chamber was set up in a Z-shape schlieren system coupled with a high-speed CMOS camera that was used to capture evolutionary behavior of flames at up to 40,000 frames per second. Pressure rise as a function of time during the flame propagation in the spherical vessel was the primary input of the multi-shell thermodynamic model used to calculate the laminar burning speed for the smooth flames. Power law correlations over a wide range of pressures (from 0.5 atm up to 4.3 atm), temperatures (from 490 K up to 620 K), and equivalence ratios (from 0.7 to 1.2) have been developed for laminar burning speeds of GTL/air flames. Experimental burning speed results have been compared with simulation values obtained by the solution of one dimensional steady premixed flame code from CANTERA using Ranzi's chemical kinetics mechanisms. Comparisons show very good agreement with the available experimental data in this study.
Numerical investigation of the effect of injection strategy on a high-pressure isobaric combustion engine
International Journal of Engine Research, Nov 25, 2021
High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has t... more High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has the prospect to achieve higher thermal efficiency compared to conventional diesel combustion. This work numerically explored the effects of various injection strategies on the combustion and emission characteristics of isobaric combustion. The study developed a mathematical model to predict the injection rate profile. After validations, extensive simulations were conducted with a peak pressure of up to 300 bar – mimicking the high-pressure unit of DCEE. Several major engine design parameters such as the exhaust recirculation gas (EGR) rate, engine speed, injection strategy, and intake pressure were varied and evaluated. The results demonstrated that a higher EGR rate resulted in a higher exhaust loss but a lower heat transfer loss owing to the lower combustion temperature, so the thermal efficiency exhibited a firstly growing and then declining trend. Besides, a higher engine speed generated a higher thermal efficiency due to the shorter combustion duration and thus lower heat transfer loss. Consequently, a peak thermal efficiency of 47.5% was achieved at EGR = 50% and 1800 rpm. The high-pressure cylinder performance can also be improved with an appropriate introduction of the isochoric combustion, but its impact on the whole DCEE setup needs further investigation.
Energies, Nov 26, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
SAE technical paper series, Mar 29, 2022
This work presents a numerical study of the Spray A (n-dodecane) characteristics using Eulerian a... more This work presents a numerical study of the Spray A (n-dodecane) characteristics using Eulerian and Lagrangian models in a finitevolume framework. The standard k- turbulence model was applied for the spray simulations. For Eulerian simulations, the X-ray measured injector geometries from the Engine Combustion Network (ECN) were employed. The High-Resolution Interface Capturing (HRIC) scheme coupled with a cavitation model was utilized to track the fluid-gas interface. Simulations under both the cool and hot ambient conditions were performed. The effects of various grid sizes, turbulence constants, nozzle geometries, and initial gas volume within the injector sac on the modeling results were evaluated. As indicated by the Eulerian simulation results, no cavitation was observed for the Spray A injector; a minimum mesh size of 15.6 m could achieve a reasonably convergent criterion; the nominal nozzle geometry predicted similar results to the X-ray measured nozzle geometry. For both the Eulerian and Lagrangian simulations, the higher C1 value of the turbulence model resulted in the lower turbulent kinetic energy, longer jet penetration, and spray cone angle. Since the Eulerian-Lagrangian coupled method has the advantage over spray distribution at the nozzle exit, it predicted a significantly better near-nozzle mixture distribution compared to the conventional Lagrangian model at a non-vaporizing condition. By employing an initial gas volume fraction of 30% within the injector sac as recommended by the Engine Combustion Network committee, the Eulerian-Lagrangian coupled method could well reproduce the experimental rate of injection profile, fuel mixture distributions, and spray penetrations at a vaporizing condition. Furthermore, the higher injection pressure promoted the vapor penetration, but it had limited effects on the liquid penetration owing to the competitive relationship between the higher spray momentum and evaporation rate. The higher ambient temperature reduced the liquid penetration for the higher evaporation rate, but it had limited effects on the vapor penetration since the spray momentum and ambient density were kept unchanged.
Investigation of the Engine Combustion Network Spray C Characteristics at High Temperature and High-Pressure Conditions Using Eulerian Model
SAE Technical Paper Series, Sep 5, 2021
Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach
Fuel, 2023
Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach
Fuel
Investigation of the Engine Combustion Network Spray C Characteristics at High Temperature and High-Pressure Conditions Using Eulerian Model
SAE Technical Paper Series, 2021
Computational Investigation of the Effects of Injection Strategy and Rail Pressure on Isobaric Combustion in an Optical Compression Ignition Engine
SAE Technical Paper Series, 2021
The high-pressure isobaric combustion has been proposed as the most suitable combustion mode for ... more The high-pressure isobaric combustion has been proposed as the most suitable combustion mode for the double compre4ssion expansion engine (DCEE) concept. Previous experimental and simulation studies have demonstrated an improved efficiency compared to the conventional diesel combustion (CDC) engine. In the current study, isobaric combustion was achieved using a single injector with multiple injections. Since this concept involves complex phenomena such as spray to spray interactions, the computational models were extensively validated against the optical engine experiment data, to ensure high-fidelity simulations. The considered optical diagnostic techniques are Mie-scattering, fuel tracer planar laser-induced fluorescence (PLIF), and natural flame luminosity imaging. Overall, a good agreement between the numerical and experimental results was obtained. Upon validation, the optimized models have been used to conduct a comparative study between the conventional diesel combustion (CDC) and the isobaric combustion cases with different pressure levels, in terms of engine performance and emissions. Compared to the CDC case, the isobaric combustion cases led to a lower NOx emission but higher sooting tendency due to the increased diffusion combustion feature, although most of the soot was oxidized in the later engine cycle. To further reduce soot emission, the effects of various rail pressures and injector holes number were evaluated. The results indicated that the higher injection pressure was more effective in soot reduction for the isobaric combustion case but it deteriorated the thermal efficiency. It was also found that increasing the number of injector holes from the reference six to ten led to the lowest soot emission without significantly affecting the efficiency
Investigation of the Cryogenic Nitrogen and Non-Cryogenic N-Dodecane and Ammonia Injections using a Real-Fluid Modelling Approach
SAE International Journal of Advances and Current Practices in Mobility
In modern compression ignition engines, the dense liquid fuel is directly injected into high pres... more In modern compression ignition engines, the dense liquid fuel is directly injected into high pressure and temperature atmosphere, so the spray transitions from subcritical to supercritical conditions. To gain better control of the spray-combustion heat release process, it is important to have a physically accurate description of the spray development process. This work explored the effect of real-fluid thermodynamics in the computational prediction of multiphase flow for two non-ideal situations: the cryogenic nitrogen and non-cryogenic n-dodecane and ammonia sprays. Three real-fluid equations of state (EoS) such as the Soave-Redlich-Kwong (SRK), Peng-Robinson (PR), and Redlich-Kwong-Peng-Robinson (RKPR) coupled with the real-fluid Chung transport model were implemented in OpenFoam to predict the real-fluid thermodynamic properties. Validations against the CoolProp database were conducted. The RKPR EoS demonstrated an overall better predictive performance compared to the SRK and PR ...
International Journal of Advances in Medicine, 2020
Background: Long-term therapy for chronic obstructive pulmonary disease (COPD) is progressing fas... more Background: Long-term therapy for chronic obstructive pulmonary disease (COPD) is progressing fast. Dual bronchodilation with long-acting muscarinic antagonist (LAMA) and long-acting β2-agonist (LABA) fixed dose combinations (FDC) have been available over the past few years. To evaluate the real-world tolerability and effectiveness of formoterol plus glycopyrronium FDC inhaler, a post-marketing surveillance study was conducted in Indian population.Methods: This was an open-label, observational registry in which COPD patients, who were prescribed forglyn (a brand of FDC of glycopyrronium 25 mcg and formoterol fumarate dihydrate 6 mcg dry powder inhalation). The effectiveness, safety and tolerability of this LAMA/LABA combination were evaluated for 4, 8 and 12 weeks. The safety and tolerability was assessed based on the incidence of adverse events (AEs). Effectiveness was evaluated based on change in total symptom score from baseline to end of 12 weeks. The forced expiratory volume in...
Fuel flexibility potential for isobaric combustion in a compression ignition engine: A computational study
Fuel, 2022
Numerical investigation of the effect of injection timing under various equivalence ratios on energy and exergy terms in a direct injection SI hydrogen fueled engine
International Journal of Hydrogen Energy, 2013
High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has t... more High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has the prospect to achieve higher thermal efficiency compared to conventional diesel combustion. This work numerically explored the effects of various injection strategies on the combustion and emission characteristics of isobaric combustion. The study developed a mathematical model to predict the injection rate profile. After validations, extensive simulations were conducted with a peak pressure of up to 300 bar – mimicking the high-pressure unit of DCEE. Several major engine design parameters such as the exhaust recirculation gas (EGR) rate, engine speed, injection strategy, and intake pressure were varied and evaluated. The results demonstrated that a higher EGR rate resulted in a higher exhaust loss but a lower heat transfer loss owing to the lower combustion temperature, so the thermal efficiency exhibited a firstly growing and then declining trend. Besides, a higher engine speed generated a higher thermal efficiency due to the shorter combustion duration and thus lower heat transfer loss. Consequently, a peak thermal efficiency of 47.5% was achieved at EGR = 50% and 1800 rpm. The high-pressure cylinder performance can also be improved with an appropriate introduction of the isochoric combustion, but its impact on the whole DCEE setup needs further investigation.
A comprehensive combustion chemistry study of n-propylcyclohexane
Combustion and Flame
Ignition delay time measurements of diesel and gasoline blends
Combustion and Flame
Impact Analysis of the Key Engine Parameters on Piston Lubrication and Friction Performance in Diesel Engines Using GT-SUITE Program
Mechanika, Jun 28, 2024
The Effect of Adding Hybrid Nanoparticles (Al2O3-TiO2) on the Performance of Parabolic Trough Solar Collectors Using Different Thermal Oils and Molten Salts
Case studies in thermal engineering, May 1, 2024
Research Square (Research Square), Apr 15, 2024
There have been continuing efforts in the Engine Combustion Network (ECN) community to understand... more There have been continuing efforts in the Engine Combustion Network (ECN) community to understand the detailed spray characteristics by investigating several standard diesel injectors. With the increasing interest in the use of alternative and renewable fuels, the present study conducted large eddy simulations with dynamic structure subgrid closure in the Eulerian volume-of-fluid (VOF) framework to identify the characteristics of oxymethylene ethers (OME), which has distinct physical and chemical properties leading to low soot emissions. In particular, the spray features of n-dodecane and OME3 were compared and analyzed in terms of their transient dynamics following the nozzle opening. ECN Spray A, C, and D were considered to assess the effects of nozzle convergence factor and nozzle diameter. The measured nozzle geometries by the Argonne National Laboratory were adopted to mimic the internal flow development. Due to the higher density of OME3, it generates a higher projected density, but a lower injection velocity is obtained. This behavior is attributed to its higher mass inertia. The diverging Spray C injector induces a significantly lower projected density and mass flow rate than the converging Spray D injector owing to cavitation just after the sharp nozzle inlet corner. By comparison, the Spray A injector generates the lowest projected density and mass flow rate for its smallest nozzle diameter. Various fuels demonstrate similar flow fields, evidenced by the significantly similar pressure distribution. The OME3 cases lead to a slightly higher temperature distribution within the nozzle channel, which is attributed to the lower turbulent kinetic energy and thus the slower heat transfer process.
Enhancing Thermal Efficiency of Passive Solar Heating Systems Through Copper-Chip Integration: Experimental Investigation and Analysis
Land Fill Gas (LFG) and Biogas are mixtures of methane (CH4) / carbon dioxide (CO2) that can be u... more Land Fill Gas (LFG) and Biogas are mixtures of methane (CH4) / carbon dioxide (CO2) that can be used as energy source in combustors. The presence of CO2 reduces the energy content per unit mass of these gases and negatively impacts the combustion stability. Laminar burning speeds of simulated LFG have been measured in this study. The experiments were conducted in a constant volume cylindrical chamber with the aid of a Z-shaped Schlieren/shadowgraph system. Pressure rise data during the flame propagation were recorded through pressure transducer on the cylindrical chamber wall and were the main input into the thermodynamic model used to measure the laminar burning speed. A high-speed CMOS camera capable of taking pictures up to 40,000 frames per second was used to determine the cellularity of the flame. Pictures of the CH4/air/ CO2 flames for different equivalence ratios and carbon dioxide percentages were taken. As the CO2 mole fraction increased the flame is less prone to become cellular. Fuel rich mixtures are less likely to become cellular than fuel lean mixtures. Experiments of CH4/air/ CO2 mixtures have been conducted to simulate LFG/Biogas and laminar burning speeds were measured. The testing sets included three CO2 mole fractions Xco2= 0%, 20%, and 30% at two initial pressures Pi= 1 atm and 2 atm. Moreover, the set covered three initial temperatures Ti =298 K, 330 K, and 360 K and three fuel air equivalence ratios of ϕ = 0.8,1.0, and 1.2. iii The effect of CO2 on laminar burning speed was determined. As the CO2 mole fraction increased from 0 to 30% the laminar burning speeds decreased. Moreover, data show that the laminar burning speed of CH4/air/ CO2 mixtures reduces with increasing pressure and increases with increasing temperature. The results show, the lowest laminar burning speed was measured at Pi = 2 atm, Ti = 298 K, ϕ = 0.8, and Xco2= 30%. iv ACKNOWKEDGMENT I would like to express my appreciation to Professor Hameed Metghalchi for his support and guidance during the learning journey at the combustion laboratory in Northeastern University. Moreover, I would like to extend my appreciation to the laboratory technician Kevin McCue and to my teammates Kevin Vien, Ziyu Wang, Guangying Yu, and Mohammed Alswat for their corporation and effort during the research process. My parents provided the love and the support that is crucial for me to keep pursuing knowledge and dream big. My wife, Nada Alsaeidi, kept encouraging me to keep a good balance between knowledge and my social life. My sweetest daughter, Lana, kept the smile on my face with her jokes. To my future me, never stop pursuing knowledge. Be wiser. Be smarter. Be happier. v
Fuel, 2017
Gas to liquid (GTL) fuel, synthesized from natural gas through Fisher-Tropsch (F-T) process, has ... more Gas to liquid (GTL) fuel, synthesized from natural gas through Fisher-Tropsch (F-T) process, has gained significant attention due to its cleaner combustion characteristics when compared to conventional fuels. Combustion properties such as flame structure and laminar burning speed of GTL/air mixture premixed flames have been investigated. The GTL fuel used in this research was provided by Air Force Research Laboratory (AFRL), designated by Syntroleum S-8, which was derived from natural gas via F-T process. A mixture of 32% iso-octane, 25% n-decane, and 43% n-dodecane by volume is considered as the surrogates of GTL fuel for filling process. Experiments were conducted using a cylindrical chamber to study the flame structure and a spherical chamber for laminar burning speeds measurement. The cylindrical chamber was set up in a Z-shape schlieren system coupled with a high-speed CMOS camera that was used to capture evolutionary behavior of flames at up to 40,000 frames per second. Pressure rise as a function of time during the flame propagation in the spherical vessel was the primary input of the multi-shell thermodynamic model used to calculate the laminar burning speed for the smooth flames. Power law correlations over a wide range of pressures (from 0.5 atm up to 4.3 atm), temperatures (from 490 K up to 620 K), and equivalence ratios (from 0.7 to 1.2) have been developed for laminar burning speeds of GTL/air flames. Experimental burning speed results have been compared with simulation values obtained by the solution of one dimensional steady premixed flame code from CANTERA using Ranzi's chemical kinetics mechanisms. Comparisons show very good agreement with the available experimental data in this study.
Numerical investigation of the effect of injection strategy on a high-pressure isobaric combustion engine
International Journal of Engine Research, Nov 25, 2021
High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has t... more High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has the prospect to achieve higher thermal efficiency compared to conventional diesel combustion. This work numerically explored the effects of various injection strategies on the combustion and emission characteristics of isobaric combustion. The study developed a mathematical model to predict the injection rate profile. After validations, extensive simulations were conducted with a peak pressure of up to 300 bar – mimicking the high-pressure unit of DCEE. Several major engine design parameters such as the exhaust recirculation gas (EGR) rate, engine speed, injection strategy, and intake pressure were varied and evaluated. The results demonstrated that a higher EGR rate resulted in a higher exhaust loss but a lower heat transfer loss owing to the lower combustion temperature, so the thermal efficiency exhibited a firstly growing and then declining trend. Besides, a higher engine speed generated a higher thermal efficiency due to the shorter combustion duration and thus lower heat transfer loss. Consequently, a peak thermal efficiency of 47.5% was achieved at EGR = 50% and 1800 rpm. The high-pressure cylinder performance can also be improved with an appropriate introduction of the isochoric combustion, but its impact on the whole DCEE setup needs further investigation.
Energies, Nov 26, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
SAE technical paper series, Mar 29, 2022
This work presents a numerical study of the Spray A (n-dodecane) characteristics using Eulerian a... more This work presents a numerical study of the Spray A (n-dodecane) characteristics using Eulerian and Lagrangian models in a finitevolume framework. The standard k- turbulence model was applied for the spray simulations. For Eulerian simulations, the X-ray measured injector geometries from the Engine Combustion Network (ECN) were employed. The High-Resolution Interface Capturing (HRIC) scheme coupled with a cavitation model was utilized to track the fluid-gas interface. Simulations under both the cool and hot ambient conditions were performed. The effects of various grid sizes, turbulence constants, nozzle geometries, and initial gas volume within the injector sac on the modeling results were evaluated. As indicated by the Eulerian simulation results, no cavitation was observed for the Spray A injector; a minimum mesh size of 15.6 m could achieve a reasonably convergent criterion; the nominal nozzle geometry predicted similar results to the X-ray measured nozzle geometry. For both the Eulerian and Lagrangian simulations, the higher C1 value of the turbulence model resulted in the lower turbulent kinetic energy, longer jet penetration, and spray cone angle. Since the Eulerian-Lagrangian coupled method has the advantage over spray distribution at the nozzle exit, it predicted a significantly better near-nozzle mixture distribution compared to the conventional Lagrangian model at a non-vaporizing condition. By employing an initial gas volume fraction of 30% within the injector sac as recommended by the Engine Combustion Network committee, the Eulerian-Lagrangian coupled method could well reproduce the experimental rate of injection profile, fuel mixture distributions, and spray penetrations at a vaporizing condition. Furthermore, the higher injection pressure promoted the vapor penetration, but it had limited effects on the liquid penetration owing to the competitive relationship between the higher spray momentum and evaporation rate. The higher ambient temperature reduced the liquid penetration for the higher evaporation rate, but it had limited effects on the vapor penetration since the spray momentum and ambient density were kept unchanged.
Investigation of the Engine Combustion Network Spray C Characteristics at High Temperature and High-Pressure Conditions Using Eulerian Model
SAE Technical Paper Series, Sep 5, 2021
Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach
Fuel, 2023
Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach
Fuel
Investigation of the Engine Combustion Network Spray C Characteristics at High Temperature and High-Pressure Conditions Using Eulerian Model
SAE Technical Paper Series, 2021
Computational Investigation of the Effects of Injection Strategy and Rail Pressure on Isobaric Combustion in an Optical Compression Ignition Engine
SAE Technical Paper Series, 2021
The high-pressure isobaric combustion has been proposed as the most suitable combustion mode for ... more The high-pressure isobaric combustion has been proposed as the most suitable combustion mode for the double compre4ssion expansion engine (DCEE) concept. Previous experimental and simulation studies have demonstrated an improved efficiency compared to the conventional diesel combustion (CDC) engine. In the current study, isobaric combustion was achieved using a single injector with multiple injections. Since this concept involves complex phenomena such as spray to spray interactions, the computational models were extensively validated against the optical engine experiment data, to ensure high-fidelity simulations. The considered optical diagnostic techniques are Mie-scattering, fuel tracer planar laser-induced fluorescence (PLIF), and natural flame luminosity imaging. Overall, a good agreement between the numerical and experimental results was obtained. Upon validation, the optimized models have been used to conduct a comparative study between the conventional diesel combustion (CDC) and the isobaric combustion cases with different pressure levels, in terms of engine performance and emissions. Compared to the CDC case, the isobaric combustion cases led to a lower NOx emission but higher sooting tendency due to the increased diffusion combustion feature, although most of the soot was oxidized in the later engine cycle. To further reduce soot emission, the effects of various rail pressures and injector holes number were evaluated. The results indicated that the higher injection pressure was more effective in soot reduction for the isobaric combustion case but it deteriorated the thermal efficiency. It was also found that increasing the number of injector holes from the reference six to ten led to the lowest soot emission without significantly affecting the efficiency
Investigation of the Cryogenic Nitrogen and Non-Cryogenic N-Dodecane and Ammonia Injections using a Real-Fluid Modelling Approach
SAE International Journal of Advances and Current Practices in Mobility
In modern compression ignition engines, the dense liquid fuel is directly injected into high pres... more In modern compression ignition engines, the dense liquid fuel is directly injected into high pressure and temperature atmosphere, so the spray transitions from subcritical to supercritical conditions. To gain better control of the spray-combustion heat release process, it is important to have a physically accurate description of the spray development process. This work explored the effect of real-fluid thermodynamics in the computational prediction of multiphase flow for two non-ideal situations: the cryogenic nitrogen and non-cryogenic n-dodecane and ammonia sprays. Three real-fluid equations of state (EoS) such as the Soave-Redlich-Kwong (SRK), Peng-Robinson (PR), and Redlich-Kwong-Peng-Robinson (RKPR) coupled with the real-fluid Chung transport model were implemented in OpenFoam to predict the real-fluid thermodynamic properties. Validations against the CoolProp database were conducted. The RKPR EoS demonstrated an overall better predictive performance compared to the SRK and PR ...
International Journal of Advances in Medicine, 2020
Background: Long-term therapy for chronic obstructive pulmonary disease (COPD) is progressing fas... more Background: Long-term therapy for chronic obstructive pulmonary disease (COPD) is progressing fast. Dual bronchodilation with long-acting muscarinic antagonist (LAMA) and long-acting β2-agonist (LABA) fixed dose combinations (FDC) have been available over the past few years. To evaluate the real-world tolerability and effectiveness of formoterol plus glycopyrronium FDC inhaler, a post-marketing surveillance study was conducted in Indian population.Methods: This was an open-label, observational registry in which COPD patients, who were prescribed forglyn (a brand of FDC of glycopyrronium 25 mcg and formoterol fumarate dihydrate 6 mcg dry powder inhalation). The effectiveness, safety and tolerability of this LAMA/LABA combination were evaluated for 4, 8 and 12 weeks. The safety and tolerability was assessed based on the incidence of adverse events (AEs). Effectiveness was evaluated based on change in total symptom score from baseline to end of 12 weeks. The forced expiratory volume in...
Fuel flexibility potential for isobaric combustion in a compression ignition engine: A computational study
Fuel, 2022
Numerical investigation of the effect of injection timing under various equivalence ratios on energy and exergy terms in a direct injection SI hydrogen fueled engine
International Journal of Hydrogen Energy, 2013
High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has t... more High-pressure isobaric combustion adopted in the double compression expansion engine (DCEE) has the prospect to achieve higher thermal efficiency compared to conventional diesel combustion. This work numerically explored the effects of various injection strategies on the combustion and emission characteristics of isobaric combustion. The study developed a mathematical model to predict the injection rate profile. After validations, extensive simulations were conducted with a peak pressure of up to 300 bar – mimicking the high-pressure unit of DCEE. Several major engine design parameters such as the exhaust recirculation gas (EGR) rate, engine speed, injection strategy, and intake pressure were varied and evaluated. The results demonstrated that a higher EGR rate resulted in a higher exhaust loss but a lower heat transfer loss owing to the lower combustion temperature, so the thermal efficiency exhibited a firstly growing and then declining trend. Besides, a higher engine speed generated a higher thermal efficiency due to the shorter combustion duration and thus lower heat transfer loss. Consequently, a peak thermal efficiency of 47.5% was achieved at EGR = 50% and 1800 rpm. The high-pressure cylinder performance can also be improved with an appropriate introduction of the isochoric combustion, but its impact on the whole DCEE setup needs further investigation.
A comprehensive combustion chemistry study of n-propylcyclohexane
Combustion and Flame
Ignition delay time measurements of diesel and gasoline blends
Combustion and Flame