Search for: combustion
Total 381 records
Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE 2004, Anaheim, CA, 13 November 2004 through 19 November 2004 ; 2004 , Pages 37-44 ; 079184708X (ISBN); 9780791847084 (ISBN) ; Ghafourian, A ; Abarham, M ; Saidi, M. H ; Sharif University of Technology
American Society of Mechanical Engineers 2004
A new experimental facility was designed, fabricated and tested to model and study the effect of bidirectional swirl flow on the rate of heat transfer to combustion chamber walls in many applications. Heat transfer to combustion chamber walls is an unwanted phenomenon. Reduction of this heat transfer can result in time and cost saving methods in design and fabrication of combustion chambers. The experimental study was performed by using propane and air with oxygen as fuel and oxidizer respectively. The location of injection ports and geometry of combustion chamber are flexible and could be varied. Tests were performed with different mass flow rates of fuel and oxidizer. For the same flow...
Welding of Al alloys through in situ fabrication of Al3Ni intermetallic compound using combustion synthesis, Article Synthesis and Reactivity in Inorganic, Metal-Organic and Nano-Metal Chemistry ; Volume 43, Issue 10 , Dec , 2013 , Pages 1390-1396 ; 15533174 (ISSN) ; Nasiri, H ; Khaki, J. V ; Mofrad, R. N ; Mohammadtaheri, M ; Sharif University of Technology
The exothermic reactions in Al+Ni system were used as a power source for welding of Al1100 alloy so that the obtained joint was reinforced with in situ produced Al3Ni intermetallic compound, simultaneously. Due to the combustion heat, the surfaces of the plates were melted down which, in turn, eventuated in formation of a strong surficial bond. The cross sections of joints were analyzed using optical microscopy, EDS-equipped scanning electron microscopy (SEM), and X-ray diffraction experiments. XRD and EDS results represented the Al3Ni intermetallic compound as the reaction product. The compressive shear strength of the joint was 20 MPa
Article Journal of Ceramic Processing Research ; Volume 13, Issue 3 , Jan , 2012 , Pages 221-225 ; 12299162 (ISSN) ; Rasouli, S ; Mohammadi, M. R ; Bovand, D ; Sharif University of Technology
Nano bioactive hydroxyapatite (Ca 10(PO 4) 6(OH) 2, HAp) ceramic powders have been synthesized by a microwave-assisted combustion method. The powders were synthesized using calcium nitrate tetrahydrate (as the source of calcium) and sodium phosphate dibasic anhydrous (as the source of phosphate ions). Glycine, citric acid and urea were used as fuesl. The influence of the fuel type on the structure and morphology of the samples was studied. Results by X-ray diffraction and Fourier-transform infrared spectroscopy showed the formation of hydroxyapatite as a major phase for all the samples. Using the Scherrer formula, the average crystallite size was found to be in the range of 10 to 28 nm....
De Gruyter 2018
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
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....
Effects of diverging angle and fuel molecular weight on NOx emissions in converging and diverging ducts, Article Journal of Engineering Research ; Volume 1, Issue 3 , 2013 , Pages 161-179 ; 23071885 (ISSN) ; Amiri, M ; Amiri, A ; Sharif University of Technology
The present paper developed and validated a numerical procedure for the calculation of turbulent combustive flows in converging and diverging ducts. Through simulation of the heat transfer processes, the amounts of production and spread of NOx pollutants were measured. Also, this paper reported the results of a numerical investigation of the effects of the fuel Molecular Weight on NOx emissions in converging and diverging ducts. The fuels which were examined were methane, naphtha, and kerosene. The differential equations in the Von-Misses coordinate system were transformed to a cross-stream coordinate system in order to concentrate more grid lines near wall boundaries. A marching integration...
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
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...
Heat transfer and energy analysis of a pusher type reheating furnace using Oxygen enhanced air for combustion, Article Journal of Iron and Steel Research International ; Volume 17, Issue 4 , 2010 , Pages 12-17 ; 1006706X (ISSN) ; Saidi, M. H ; Sharif University of Technology
Oxy-fuel firing is more energy efficient and environmental friendly than conventional air-fuel firing and its application to reheating furnaces has hegun since 1990s. A computational method was presented to predict the steady heat transfer to the billets and temperature distribution in a continuous pusher type reheating furnace in which combustion air was enhanced by oxygen. Radiation heat flux calculated from the radiation heat exchange within the furnace was modeled using the FVM considering the effects of furnace walls and billets. Energy consumption per ton of steel, production rate and thermal efficiency of furnace, and trend of NOx emission in various levels of oxygen enrichment were...
Article International Journal of Hydrogen Energy ; Volume 43, Issue 32 , 2018 , Pages 15551-15563 ; 03603199 (ISSN) ; Mardani, A ; Sharif University of Technology
Moderate or intense low-oxygen dilution (MILD) combustion is a novel combustion technology with the comparable chemical and turbulent mixing timescales. In the most of literatures, relatively expensive volume-based models are recommended for this combustion regime while this regime is not completely idealized homogenized reactor and nor strong flamelet like. This paper is focused on the assessment of the lower cost, flamelet approach for MILD condition. In this way, simplifying JHC burner of Dally et al. is considered to model using RANS approach. The effects of inclusion of unity versus non-unity Lewis numbers, radiation heat transfer, and various scalar dissipation rates are evaluated....
M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad ; Hejranfar, Kazem
Nowadays, one of the most important desires of the human being is to reduce his living environmental pollution. Using the diluted combustion systems in new gas turbines in order to produce the minimum amount of has been done to satisfy this desire. It should be noted that reducing this amount and using the lower flame temperature will result in some consequences. The most important problem occurred in industrial and aerial gas turbines are the instability of the combustion due to dilution of the fuel to air mixture which it results in heat release fluctuations. If the heat release fluctuations and acoustic pressure are in the same phases, the amplitude of the fluctuations will increase which...
Article Thermal Science ; Volume 19, Issue 1 , 2015 , Pages 21-34 ; 03549836 (ISSN) ; Tabejamaat, S ; Sharif University of Technology
Serbian Society of Heat Transfer Engineers 2015
In this paper, turbulent non-premixed CH4+H2 jet flame issuing into a hot and diluted co-flow air is studied numerically. This flame is under condition of the moderate or intense low-oxygen dilution combustion regime and related to published experimental data. The modelling is carried out using the EDC model to describe turbulence-chemistry interaction. The DRM-22 reduced mechanism and the GRI2.11 full mechanism are used to represent the chemical reactions of H2/methane jet flame. The flame structure for various O2 levels and jet Reynolds numbers are investigated. The results show that the flame entrainment increases by a decrease in O2 concentration at air side or jet Reynolds number. Local...
Article Journal of Engineering for Gas Turbines and Power ; Volume 129, Issue 2 , 2007 , Pages 622-624 ; 07424795 (ISSN) ; Saidi, M. H ; Jahangirian, S ; Abarham, M ; Sharif University of Technology
A new experimental facility was designed, fabricated, and tested to model and study the effect of bidirectional swirl flow on the rate of heat transfer to combustion chamber walls. Reduction of this heat transfer can result in time and cost of design and fabrication methods of combustion chambers. The experimental study was performed using propane and air with oxygen as fuel and oxidizer respectively. For similar flow rates, in cases where bidirectional flow was present, wall temperature reductions of up to 70% were observed. In cases where only some of the oxidizer was injected from the chamber end to generate the bidirectional swirl flow, the lowest wall temperature existed. This can be...
Ph.D. Dissertation Sharif University of Technology ; Saidi, Mohammad Hassan ; Mozafari, Ali Asghar ; Ghafourian, Akbar
Vortex engine has shown to be a credible substitute in thermal power and aerospace industries mainly due to their advantages such as better mixing, improved combustion, and considerable cooled walls of combustion chamber. The engine geometry and tangential inlet oxidizer create inner and outer vortices rotating in the same angular direction. The inner vortex moves from head to the end of engine in the axial direction and outer vortex moves in the opposite direction. In the vortex engine, vortices affect spray droplets and force them to have a spiral path and apply a centrifugal force on the droplets to push them towards sidewall. Also axial relative velocity of droplets and flow filed act as...
M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad
By creating constant volume combustion, the rotating detonation chamber increases efficiency compared to conventional constant pressure chambers. The RDC is smaller and mechanically more straightforward than the other detonation chambers, such as the pulse chamber. In the current research, an RDC with an outer diameter of 76 mm and an inner diameter of 64 mm, using hydrogen and air as fuel and oxidizer, has been successfully tested and data collected in the laboratory. Data acquisition has been made by high-frequency and pressure measurement facilities. In the following, the chamber has been optimized and improved by applying parametric studies (equivalence ratio, mass flow rate, channel...
An investigation on mechanical properties of Alumina-Zirconia-Magnesia spinel composite ceramics fabricated by gel-casting using solution combustion synthesized powder, Article Materials Science and Engineering A ; Volume 587 , 2013 , Pages 336-343 ; 09215093 (ISSN) ; Faghihi Sani, M. A ; Sharif University of Technology
Addition of spinel (MgAl2O4) to Al2O3-ZrO2 composite inhibits alumina grain growth and produces phase boundaries that leads to formation of a ceramic matrix composite with special mechanical properties such as high temperature superplastic deformation. However, the room temperature mechanical properties of Alumina-zirconia-magnesia spinel composite (AZM) such as fracture toughness were rarely investigated by researchers. In this research the AZM nanocomposite powders were synthesized via the solution combustion method. The dense AZM composite samples were fabricated through gelcasting process. Phase analysis studies were performed on both powder and sintered samples and the effects of spinel...
Photocatalytic decolorization of methylene blue using immo bilized ZnO nanoparticles prepared by solution combustion method, Article Desalination and Water Treatment ; Volume 44, Issue 1-3 , May , 2012 , Pages 174-179 ; 19443994 (ISSN) ; Masoumbeigi, H ; Soltani, R. D. C ; Khataee, A. R ; Hashemiyan, S ; Sharif University of Technology
Taylor and Francis Inc 2012
Photocatalytic decolorization of methylene blue (MB) in aqueous solution was investigated using ZnO nanoparticles immobilized on glass plate. The ZnO nanoparticles were prepared by solution combustion method (SCM) using zinc nitrate as oxidant and glycine as fuel. In the slurry ZnO system the separation and recycling of the photocatalyst is practically difficult. Thus, the ZnO nanoparticles were immobilized on glass supports to solve this problem. The effects of process parameters like, catalyst loading, initial dye concentration, and UV-radiation intensity have been investigated. The best results of MB removal were reported in the 1800 μW cm-2 UVC using two layers immobilized ZnO...
Article Processes ; Volume 8, Issue 8 , 2020 ; Hakkaki Fard, A ; Firoozabadi, B ; Sharif University of Technology
MDPI AG 2020
The application of incinerators for the municipal solid waste (MSW) is growing due to the ability of such instruments to produce energy and, more specifically, reduce waste volume. In this paper, a numerical simulation of the combustion process with the help of the computational fluid dynamics (CFD) inside a portable (mobile) incinerator has been proposed. Such work is done to investigate the most critical parameters for a reliable design of a domestic portable incinerator, which is suitable for the Iranian food and waste culture. An old design of a simple incinerator has been used to apply the natural gas (NG), one of the available cheap fossil fuels in Iran. After that, the waste height,...
Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 27, Issue 2 , 2008 , Pages 93-101 ; 10219986 (ISSN) ; Kharrat, R ; Rashtchian, D ; Vossoughi, S ; Saraji, S ; Sharif University of Technology
In this work, the potential of auto-ignition of heavy oil during in-situ combustion (ISC) process was studied. Kinetic studies were carried out using Thermo Gravimetric Analyzer (TGA), Differential Scanning Calorimetry (DSC) and Accelerating Rate Calorimetric (ARC) techniques. Effects of oxygen partial pressure, reservoir pressure and clay on auto ignition condition were investigated on a number of different heavy oil samples from south west Iran mixed with silica sand or crushed carbonate rock and clay. Based on the experimental results obtained by TGA runs, the kinetic equation was derived for different oil samples in the presence of different sands. Effect of partial pressure of oxygen in...
Experimental investigation on the effects of swirlers configurations and air inlet partitioning in a partially premixed double high swirl gas turbine model combustor, Article Journal of Energy Resources Technology, Transactions of the ASME ; Volume 143, Issue 1 , 2021 ; 01950738 (ISSN) ; Rekabdarkolaei, B. A ; Rastaaghi, H. R ; Sharif University of Technology
American Society of Mechanical Engineers (ASME) 2021
In this work, a double-high swirl gas turbine model combustor (GTMC) has been experimentally investigated to identify the effects of air partitioning and swirlers geometry on combustion characteristics in terms of flame stability, exhaust gas temperature, NOx generation, and combustion efficiency. This high swirl model combustor is originally developed in the German Aerospace Center (DLR) and known as GTMC and recently reconstructed at Sharif University's Combustion Laboratory (named as SGTMC). Here, SGTMC run for liquefied petroleum gas (LPG) fuel and air oxidizer at room temperature and atmospheric pressure. Eleven different burner geometries, M1-M11, are considered for the aims of this...
Article Applicable Analysis ; Volume 77, Issue 3-4 , 2001 , Pages 405-418 ; 00036811 (ISSN) ; Razani, A ; Sharif University of Technology
The existence of travelling wave solution to equations of a viscous heat conducting combustible fluid is proved. The reactions are assumed to be one step exothermic reactions with a natural discontinuous reaction rate function. The problem is studied for a general gas. Instead of assuming the ideal gas conditions we consider a general thermodynamics which is described by a fairly mild set of hypotheses. Travelling waves for detonations reduce to specific heteroclinic orbits of a discontinuous system of ODE's. The existence proof for heteroclinic orbits corresponding to weak and strong detonation waves is carried out by some general topological arguments in ODE. The uniqueness and...