Loading...
Search for:
direct-injection
0.006 seconds
Total 26 records
Lean partially premixed combustion investigation of methane direct-injection under different characteristic parameters
, Article ASME 2013 Internal Combustion Engine Division Fall Technical Conference, ICEF 2013, Dearborn, MI, 13 October 2013 through 16 October 2013 ; Volume 1 , 2013 ; 9780791856093 (ISBN) ; Metghalchi, H ; Hannani, S. K ; Hemmati, H ; Ebrahimi, R ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2013
Abstract
The effects of hydrogen addition, diluent addition, injection pressure, chamber pressure, chamber temperature and turbulence intensity on methane-air partially premixed turbulent combustion have been studied experimentally using a constant volume combustion chamber (CVCC). The fuel-air mixture was ignited by centrally located electrodes at given spark delay times of 1, 5, 40, 75 and 110 milliseconds. Experiments were performed for a wide range of hydrogen volumetric fractions (0% to 40%), exhaust gas recirculation (EGR) volumetric fractions (0% to 25% as a diluent), injection pressures (30-90 bar), chamber pressures (1-3 bar), chamber temperatures (298-432 K) and overall equivalence ratios...
Large eddy simulation of GDI single-hole and multi-hole injector sprays with comparison of numerical break-up models and coefficients
, Article Journal of Applied Fluid Mechanics ; Volume 9, Issue 2 , 2016 , Pages 1013-1022 ; 17353572 (ISSN) ; Hosseini, V ; Afshin, H ; Allocca, L ; Baloo, M ; Sharif University of Technology
Isfahan University of Technology
2016
Abstract
In the present study the fuel spray of a gasoline direct injected engine with multi-hole injector is simulated. Simulation inputs data, injection flow rate and spray cone angle are obtained from previous experimental studies. Log-normal distribution with different standard deviation is used for initial droplet size as the primary break-up model in order to reach the agreement between experimental and calculated spray tip penetration. As the first step, only one plume of spray injected into a quiescent air environment is simulated and validated by varying break-up model and standard deviation. Then, with coefficient obtained from the single jet simulation all six spray jets are simulated...
Lean partially premixed combustion investigation of methane direct-injection under different characteristic parameters
, Article Journal of Energy Resources Technology, Transactions of the ASME ; Vol. 136, issue. 2 , 2014 ; ISSN: 01950738 ; Metghalchi, H ; Hannani, S. K ; Hemmati, H ; Ebrahimi, R ; Sharif University of Technology
Abstract
The effects of hydrogen addition, diluent addition, injection pressure, chamber pressure, chamber temperature and turbulence intensity on methane-air partially premixed turbulent combustion have been studied experimentally using a constant volume combustion chamber (CVCC). The fuel-air mixture was ignited by centrally located electrodes at given spark delay times of 1, 5, 40, 75, and 110 ms. Experiments were performed for a wide range of hydrogen volumetric fractions (0% to 40%), simulated diluent volumetric fractions (0% to 25% as a diluent), injection pressures (30-90 bar), chamber pressures (1-3 bar), chamber temperatures (298-432 K) and overall equivalence ratios of 0.6, 0.8, and 1.0....
Manufacturing Constant Volume Combustion Chamber and Simulation and Analysis of the Flame front Development
, M.Sc. Thesis Sharif University of Technology ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
The application of internal combustion engine is vast in different context, such as transportation and power generation. Therefore to investigation of these objects and the importance of flame front development, a combustion chamber with constant volume is designed and manufactured. The chamber designing is based on the experimental knowledge and numerical simulation of chamber and glasses. The combustion chamber made of stainless steel and contained transparent quartz glasses in both side of it to provide the ability of using schlieren photography method and investigation of flame. The great advantage of present chamber is the capability of different type of combustion, including fuel and...
Experimental and Theoretical Investigation of Mixture Formation in CNG Direct Injection of Spark Ignition
, Ph.D. Dissertation Sharif University of Technology ; Saidi, Mohammad Hasan (Supervisor) ; Mozafari, Ali Asghar (Supervisor)
Abstract
Due to increasing of internal combustion engine applications in metropolitan, reduction of emission is one of the challenging issues for engine companies. Natural gas is a promising fuel for the strict legislation of emission in many countries. Vast variety of natural gas sources in Iran and also lower carbon to hydrogen content of natural gas motivates us to use this fuel for engine application. Using natural gas also helps to increase the variety of fuel basket in Iran. Present research has focused on mixture formation and injection characteristics of natural gas direct injection engine. Injection and mixture formation in direct injection engines is very important for good combustion and...
Numerical Modeling of Ethanol & Gasoline Direct Injection Spary in an Combustion Chamber
, M.Sc. Thesis Sharif University of Technology ; Saidi, Mohammad Hassan (Supervisor) ; Mozafari, Ali Asghar (Supervisor)
Abstract
First studies in internal combustion engines have focused on increasing engine power and efficiency, reducing engine volume and improving fuel quality. However, nowadays most studies are concentrated on decreasing exhaust emissions and usage of regenerative fuels while maintaining engine size, efficiency and power. Surveying fuel type in direct injection engines, requires investigation of microscopic and macroscopic spray characteristics including spray tip penetration, spray cone angle, spray area and sauter mean diameter, since these parameters determine air-fuel mixture quality. In this study, spray of ethanol as a regenerative fuel that reduces emissions such as NOx and CO is...
Fundamental study of spray and partially premixed combustion of methane/air mixture
, Article ASME 2012 Internal Combustion Engine Division Fall Technical Conference, ICEF 2012 ; 2012 , Pages 417-426 ; 9780791855096 (ISBN) ; Metghalchi, H ; Moghaddas, A ; Hannani, S. K ; Ebrahimi, R ; Sharif University of Technology
2012
Abstract
This study presents fundamentals of spray and partially premixed combustion characteristics of directly injected methane inside a constant volume combustion chamber (CVCC). The constant volume vessel is a cylinder with inside diameter of 135 mm and inside height of 135 mm. Two end of the vessel are equipped with optical windows. A high speed complementary metal oxide semiconductor (CMOS) camera capable of capturing pictures up to 40, 000 frames per second is used to observe flow conditions inside the chamber. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel-air mixture in the vessel, similar to that in a compressed natural gas (CNG) direct...
Experimental investigation of spray characteristics of a modified bio-diesel in a direct injection combustion chamber
, Article Experimental Thermal and Fluid Science ; 2016 ; 08941777 (ISSN) ; Saidi, M. H ; Hajinezhad, A ; Mozafari, A. A ; Sharif University of Technology
Elsevier Inc
2016
Abstract
Macroscopic and microscopic characteristics of spray of a Modified Bio-diesel Fuel (MBF), applying direct injection system have been explored and compared with those of conventional diesel fuel. MBF is a new combination of bio-diesel, molasses bio-ethanol, and water, which has been kept as a single-phase bio-fuel, employing an emulsifier. Lower emissions and production costs, higher oxygen content and cetane number are the key advantages of the MBF to be replaced by conventional fossil fuels in internal combustion engines. Applying atomization model, the spray atomization properties such as Ohnesorge number and Sauter Mean Diameter (SMD) have been investigated. Air entrainment analysis has...
Experimental investigation of spray characteristics of a modified bio-diesel in a direct injection combustion chamber
, Article Experimental Thermal and Fluid Science ; Volume 81 , 2017 , Pages 445-453 ; 08941777 (ISSN) ; Saidi, M. H ; Hajinezhad, A ; Mozafari, A. A ; Sharif University of Technology
Elsevier Inc
2017
Abstract
Macroscopic and microscopic characteristics of spray of a Modified Bio-diesel Fuel (MBF), applying direct injection system have been explored and compared with those of conventional diesel fuel. MBF is a new combination of bio-diesel, molasses bio-ethanol, and water, which has been kept as a single-phase bio-fuel, employing an emulsifier. Lower emissions and production costs, higher oxygen content and cetane number are the key advantages of the MBF to be replaced by conventional fossil fuels in internal combustion engines. Applying atomization model, the spray atomization properties such as Ohnesorge number and Sauter Mean Diameter (SMD) have been investigated. Air entrainment analysis has...
Waste heat recovery of the turbocharged engine employing vortex tube for improving transient cold start
, Article Journal of Mechanical Science and Technology ; Volume 36, Issue 2 , 2022 , Pages 1015-1024 ; 1738494X (ISSN) ; Chitsaz, I ; Hanani, S. K ; Monemi, M ; Sharif University of Technology
Korean Society of Mechanical Engineers
2022
Abstract
Most of the vehicle pollutants during emission tests are raised from catalyst inefficiency during cold start. Catalysts usually convert harmful emissions only when their temperature reaches around 250 °C to 350 °C. In this research, the vortex tube is implemented to recover the waste heat energy of exhaust gas during the cold start to improve catalyst heating. The experiments are conducted on the turbocharged direct-injection gasoline engine to extract the boundary conditions of numerical simulations. Numerical simulations are performed to evaluate the effects of different hot exhaust mass fractions on the flow regime and waste heat recovery. The results reveal that the level of turbulence...
Numerical and Experimental Study of the Partially Premixed Combustion Used in a Compressed Natural Gas Spark-Ignition Direct-Injection Engine
, Ph.D. Dissertation Sharif University of Technology ; Kazemzadeh Hannani, Siamak (Supervisor) ; Ebrahimi, Reza (Supervisor) ; Metghalchi, Hamid (Co-Advisor)
Abstract
Direct injection spark ignition lean burn engine with stratified mixture is concerned recently and research and development are in its initial stage. In this thesis, at first a thermodynamic simulation of these engines was done for investigating of stratified mixture effects on combustion characterization and compare it with homogeneous one. In this modeling we use from turbulent flame speed model for mass burning rate analysis, multizone model for exact measuring of temperature distribution, full chemical kinetic model for emission concentrations and some proposed mixture formation for predicting of stratified mixture. The results shown that stratification is caused to improve combustion...
Experimental and Analytical Investigation of Bio-fuels Blends in the Direct Injection Engine
, Ph.D. Dissertation Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor) ; Mozaffari, Ali Asghar (Co-Advisor) ; Hajinezhad, Ahmad (Co-Advisor)
Abstract
The growing use of fossil fuels and their impacts on the environmental pollution, mostly originating from internal combustion engines, is one of the important issues in environmentally friendly energy management. One of the key solutions to improve engine performance and reduce exhaust emissions of internal combustion engines is direct injection of bio-fuels. In this regard, in the present study some new biofuels such as Bio-Norouzak, Modified Bio-Ethanol (MBE), and Modified Bio-Diesel (MBF) have been introduced and effects of different parameters on their sprays have been investigated experimentally and analytically. The literature survey shows there is not any comprehensive study on the...
Fuel Injection Parameters Optimisation to Obtain High Fuel Economy and Low Engine Emissions in a Gasoline Direct Injection Engine
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Hamid (Supervisor)
Abstract
Energy crisis is one of the crises which human beings face these days. Optimizing the operation of energy consuming machines is one of the most effective methods in decreasing energy consumption. Gasoline direct injection engines as new achievements in automobile and propulsion industry, reduce fuel consumption by increasing the engine efficiency. In these types of engines, a high pressure injector injects fuel directly into the combustion chamber instead of injecting fuel in intake ports. Thus, because of evaporation cooling, the mixture cools down, so the possibility of achieving higher compression ratios in higher engine speeds and loads, without occurrence of knock is provided. Increase...
Numerical Simulation of Spray and Combustion in a Gasoline Direct Injection (GDI) Engine
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor) ; Afshin, Hossein (Supervisor)
Abstract
Energy crisis is one of the crises which human beings face these days. Optimizing the operation of energy consuming machines is one of the most effective methods in decreasing energy consumption. Gasoline direct injection engines as new achievements in automobile and propulsion industry, reduce fuel consumption by increasing the engine efficiency. In these types of engines, a high pressure injector injects fuel directly into the combustion chamber instead of injecting fuel in intake ports. Thus, because of evaporation cooling, the mixture cools down, so the possibility of achieving higher compression ratios in higher engine speeds and loads, without occurrence of knock is provided. Increase...
Experimental & Numerical Investigations of the effects of the Intake Port Geometry on the In-Cylinder Flow of Direct Injection Spark Ignition Engine
, Ph.D. Dissertation Sharif University of Technology ; Shafii, Behshad (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
The design of inlet ports for spark ignition internal combustion engines has a direct and well-known influence on performance and emissions as a result of changes in volumetric efficiency and fuel burn rate.The design of ports is becoming more critical as SI engines are developed further to meet increasingly stringent exhaust emissions legislations. Lately further emphasis has been placed on port design by the re-emergence of the direct injection gasoline engine.
Due to lean burning, combustion instability and increasing the cycle to cycle variations, in the direct injection engine, combustion charactersitics will be improved by increasing the tumble in-cylinder flow and the turbulence...
Due to lean burning, combustion instability and increasing the cycle to cycle variations, in the direct injection engine, combustion charactersitics will be improved by increasing the tumble in-cylinder flow and the turbulence...
CFD based optimization of the mixture formation in spark ignition direct injection CNG engine
, Article Scientia Iranica ; Vol. 21, issue. 5 , 2014 , p. 1621-1634 ; Saidi, M. H ; Mozafari, A. A ; Sharif University of Technology
Abstract
This paper describes optimization of the combustion chamber geometry and injection timing of a new generation of EF7 engine, where CNG is directly injected to the combustion chamber, with the aim of providing the best mixture at low and high speeds. The Multi-Objective Genetic Algorithm (MOGA) is coupled with the KIVA Computational Fluid Dynamics (CFD) code, with grid generation, in order to maximize the flammable mass of the mixture. This would result in better combustion and improved fuel economy. The optimization variables related to the combustion chamber are seven geometry variables and injection timing. Through the present optimization, a great improvement in mixture distribution is...
Flux estimation by asymmetric carrier injection for sensorless direct torque control of PMSM
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 44-50 ; 9781467301114 (ISBN) ; Tahami, F ; Sharif University of Technology
2012
Abstract
The combination of direct torque control and permanent magnet synchronous motors (PMSMs) provides a highly dynamic drive. In this paper direct torque control method of PMSM is merged with a sensorless control algorithm and a robust flux observer is proposed which results in a high performance highly reliable drive. First a high frequency signal injection method within DTC algorithm is introduced to estimate the rotor position of PMSM. Then the method is modified in order to estimate stator dynamic inductances. The stator inductances are then used in a current model flux observer
Experimental and numerical investigation on the jet characteristics of spark ignition direct injection gaseous injector
, Article Applied Energy ; Volume 105 , 2013 , Pages 8-16 ; 03062619 (ISSN) ; Saidi, M. H ; Mozafari, A. A ; Hajialimohammadi, A ; Sharif University of Technology
2013
Abstract
Natural gas has widely been used as a fuel in conventional Diesel and spark ignition engines. The better understanding of injector parameters on the jet structure is helpful for the combustion optimization. This paper presents an experimental and numerical study on the jet structure of gaseous fuel injector in spark ignition direct injection engine by Schlieren technique and numerical procedure. Helium was injected through a gaseous injector at the different pressure ratios and nozzle diameters to understand the effects of nozzle geometry and pressure ratio for a dedicated correlation of CNG-SIDI injector. It was found that higher pressure ratio and exit nozzle diameter led to more tip...
Design and manufacturing of a constant volume test combustion chamber for jet and flame visualization of CNG direct injection
, Article Applied Mechanics and Materials ; Volume 217-219 , 2012 , Pages 2539-2545 ; 16609336 (ISSN) ; 9783037855027 (ISBN) ; Ahmadisoleymani, S. S ; Abdullah, A ; Asgari, O ; Rezai, F
2012
Abstract
Constant volume transparent test combustion chambers are extensively used for investigating injection and fuel burning properties of various combustion engines. Their configuration depends on the engine type and the research purpose. Material of components, shape and dimensions of the chamber and its parts, ease of use, accessibility, sealing and safety of the assembly are the parameters needed to be considered in designing the test cell. This paper explains, structural design of a test combustion chamber and its optical windows using finite element analysis of ANSYS 12.0 software for bearing high pressure variations and thermal shocks of combustion. It was designed for conducting CNG direct...
Magnetic resonance imaging tracking of stem cells in vivo using iron oxide nanoparticles as a tool for the advancement of clinical regenerative medicine
, Article Chemical Reviews ; Volume 111, Issue 2 , November , 2011 , Pages 253-280 ; 00092665 (ISSN) ; Hosseinkhani, H ; Hosseinkhani, M ; Boutry, S ; Simchi, A ; Shane Journeay, W ; Subramani, K ; Laurent, S ; Sharif University of Technology
2011
Abstract
Fetal stem cells, which can be isolated from the organs of fetuses, differentiate along multiple lineages. Their advantages over their adult counterparts include better intrinsic homing and engraftment and lower immunogenicity, and they are less ethically contentious. It is noteworthy that Mesenchymal Stem Cells (MSC) can be activated and mobilized at the site of damaged tissue. Since vascular delivery suffers from a pulmonary first pass effect, direct or systemic injection of MSCs into the damaged tissue is preferred, particularly in the case of versatile tissue ischemia. Ultrasound applies acoustic energy with a frequency above human hearing (20 kHz). Ultrasound imaging or sonography...