Moaz Al-lehaibi | Umm Al-Qura University, Makkah, Saudi Arabia (original) (raw)

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Papers by Moaz Al-lehaibi

Research paper thumbnail of Impact Analysis of the Key Engine Parameters on Piston Lubrication and Friction Performance in Diesel Engines Using GT-SUITE Program

Research paper thumbnail of 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 paper thumbnail of Comparison of Transient Spray Characteristics of N-dodecane and OME 3 Using Large Eddy Simulation

Research Square (Research Square), Apr 15, 2024

Research paper thumbnail of Enhancing Thermal Efficiency of Passive Solar Heating Systems Through Copper-Chip Integration: Experimental Investigation and Analysis

Research paper thumbnail of Comparative Study of Oxymethylene Ether 3 (OME3) in Isobaric Combustion Mode: Numerical Study

Research Square (Research Square), Mar 21, 2024

Research paper thumbnail of Laminar burning speed measurments of methane /air/carbon dioxide mixtures

Research paper thumbnail of Flame structure and laminar burning speed of gas to liquid fuel air mixtures at moderate pressures and high temperatures

Research paper thumbnail of 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.

Research paper thumbnail of Comparative Study of Spark-Ignited and Pre-Chamber Hydrogen-Fueled Engine: A Computational Approach

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

Research paper thumbnail of Investigation of the Engine Combustion Network Spray A Characteristics using Eulerian and Lagrangian Models

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 C1 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.

Research paper thumbnail of 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

Research paper thumbnail of Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach

Research paper thumbnail of Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach

Research paper thumbnail of Investigation of the Engine Combustion Network Spray C Characteristics at High Temperature and High-Pressure Conditions Using Eulerian Model

SAE Technical Paper Series, 2021

Research paper thumbnail of 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

Research paper thumbnail of 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 ...

Research paper thumbnail of Effectiveness and tolerability of formoterol plus glycopyrronium combination in patients with chronic obstructive pulmonary disease: FINE registry

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...

Research paper thumbnail of Fuel flexibility potential for isobaric combustion in a compression ignition engine: A computational study

Research paper thumbnail of 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.

Research paper thumbnail of A comprehensive combustion chemistry study of n-propylcyclohexane

Research paper thumbnail of Impact Analysis of the Key Engine Parameters on Piston Lubrication and Friction Performance in Diesel Engines Using GT-SUITE Program

Research paper thumbnail of 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 paper thumbnail of Comparison of Transient Spray Characteristics of N-dodecane and OME 3 Using Large Eddy Simulation

Research Square (Research Square), Apr 15, 2024

Research paper thumbnail of Enhancing Thermal Efficiency of Passive Solar Heating Systems Through Copper-Chip Integration: Experimental Investigation and Analysis

Research paper thumbnail of Comparative Study of Oxymethylene Ether 3 (OME3) in Isobaric Combustion Mode: Numerical Study

Research Square (Research Square), Mar 21, 2024

Research paper thumbnail of Laminar burning speed measurments of methane /air/carbon dioxide mixtures

Research paper thumbnail of Flame structure and laminar burning speed of gas to liquid fuel air mixtures at moderate pressures and high temperatures

Research paper thumbnail of 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.

Research paper thumbnail of Comparative Study of Spark-Ignited and Pre-Chamber Hydrogen-Fueled Engine: A Computational Approach

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

Research paper thumbnail of Investigation of the Engine Combustion Network Spray A Characteristics using Eulerian and Lagrangian Models

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 C1 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.

Research paper thumbnail of 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

Research paper thumbnail of Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach

Research paper thumbnail of Numerical investigation of n-dodecane ECN spray and combustion characteristics using the one-way coupled Eulerian-Lagrangian approach

Research paper thumbnail of Investigation of the Engine Combustion Network Spray C Characteristics at High Temperature and High-Pressure Conditions Using Eulerian Model

SAE Technical Paper Series, 2021

Research paper thumbnail of 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

Research paper thumbnail of 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 ...

Research paper thumbnail of Effectiveness and tolerability of formoterol plus glycopyrronium combination in patients with chronic obstructive pulmonary disease: FINE registry

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...

Research paper thumbnail of Fuel flexibility potential for isobaric combustion in a compression ignition engine: A computational study

Research paper thumbnail of 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.

Research paper thumbnail of A comprehensive combustion chemistry study of n-propylcyclohexane