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Effects of preheating temperature and dilution level of oxidizer, fuel composition and strain rate on NO emission characteristics in the syngas moderate or intense low oxygen?…

E Ebrahimi Fordoei, Kiumars Mazaheri
Journal PapersFuel , Volume 285 , 2021 February 1, {Pages 119118 }

Abstract

The aims of present study are to investigate the effective parameters in syngas MILD combustion, including preheating temperature and dilution level of oxidizer, syngas composition and flow structure on NO emission characteristics. For this purpose, counterflow syngas flame simulations are employed at the oxidizer preheating temperatures 1100–2100?K, oxygen mole fractions 2–12%, three syngas mixtures (10%H2/90%CO, 50%H2/50%CO, and 90%H2/10%CO) and the strain rate ranges 25–4000?s−1. Moreover, the effect of methane in the syngas composition as a diluent is studied on NO emission index. For the independence of the results from other parameters, simulations are performed at the equivalence ratio 1 and for the formation of reaction zone

Effects of hydrogen addition to methane on the thermal and ignition delay characteristics of fuel-air, oxygen-enriched and oxy-fuel MILD combustion

EE Fordoei, K Mazaheri, A Mohammadpour
Journal Papers , , {Pages }

Abstract

Thermo-hydrodynamic effects of the Ethylene reactive flow on convecting hot spots using LES

N Hajialigol, K Mazaheri, A Fattahi
Journal Papers , , {Pages }

Abstract

Effects of preheating temperature and dilution level of oxidizer, fuel composition and strain rate on NO emission characteristics in the syngas moderate or intense low oxygen …

EE Fordoei, K Mazaheri
Journal Papers , , {Pages }

Abstract

Maps of flame dynamics for premixed lean hydrogen-air combustion in a heated microchannel

Alireza Alipoor, Kiumars Mazaheri
Journal PapersEnergy , Volume 194 , 2020 March 1, {Pages 116852 }

Abstract

In the present work, flame dynamics are extracted for combustion of premixed lean hydrogen-air in a heated microchannel using numerical simulation. In this simulation, Navier-Stokes equations along with energy and species conservation equations are considered by formulation of low Mach number and with consideration of detail chemical kinetics. Regarding different conditions, three dynamics are observed in the microchannel which are periodic repetitive ignition-extinction, steady symmetric flame, and steady asymmetric flame. The effects of different parameters such as inlet velocity, equivalence ratio, and channel width are investigated on the flame dynamics. The periodic repetitive ignition-extinction dynamics is observed at low velocities

Large eddy simulation on combustion noise in a non-premixed turbulent free flame: Effect of oxygen enhancement

Faeze Ehsaniderakhshan, Kiumars Mazaheri, Yasser Mahmoudi
Journal PapersEnergy , Volume 210 , 2020 November 1, {Pages 118534 }

Abstract

Present work examines the effect of a low-level oxygen concentration enhancement in the oxidizer stream, on the generation of direct combustion noise in a non-premixed turbulent free flame. A hybrid approach utilizing a large eddy simulation, partially stirred reactor combustion model, and Lighthill analogy was employed to predict the sound pressure level in the farfield of the flame. Contributions of different noise sources, including heat release rate and, mole consumption and production rate fluctuations are calculated to predict the sound pressure level in the farfield. Results show that, in comparison to the flame burning with air, the higher temperature in oxygen enhanced flame leads to an increase in the heat release rate and an incr

Investigating the effect of presence of porous media in the micro combustion chamber on radiation efficiency

H Faramarzpour, K Mazaheri, AR Alipoor, Gh Oliayi
Journal Papers , Volume 49 , Issue 48900445, 2020 January 1, {Pages 183-192 }

Abstract

In the present numerical study, 2D effect of presence of porous media on radiative efficiency in micro combustion chamber is investigated with taking account of conservative equations of momentum, energy and species. The effect of equivalence ratio of mixture and thermal conductivity of combustor wall as key parameters on radiative efficiency are also studied.. Based on simulation results, using of porous media in combustion chamber causes to increase of mean wall temperature and consequently radiation efficiency of micro combustor will increased. moving flame front toward downstream and reduction of maximum flow temperature is as result of applying porous media as well. Furthermore, maximum radiation efficiency is occurred in lean conditio

Numerical Study on the Heat Transfer Characteristics, Flame Structure, and Pollutants Emission in the MILD Methane-Air, Oxygen-Enriched and Oxy-Methane Combustion

E Ebrahimi Fordoei, Kiumars Mazaheri, Amirreza Mohammadpour
Journal PapersEnergy , 2020 December 8, {Pages 119524 }

Abstract

Present study provides the comprehensive investigation on the different characteristics of MILD oxygen-enriched and oxy-methane combustion such as heat transfer, ignition delay, flame color, flame structure, emissions of CO and NOx (as air pollutants) by the adding of CO2 to the oxidizer. The MILD furnace of Lisbon University is modeled using the standard k-ε turbulence model and detailed chemical mechanism of GRI2.11. Original, extended and new optimized EDC (“EDC2020”) models are applied for the turbulence-chemistry interaction modeling. Additionally, a perfectly stirred reactor (PSR) analysis alongside with CFD simulation is used for better understanding the combustion process. The results indicate that by replacing of CO2 with N2,

Numerical study of the effect of carbon dioxide injection on flame structure in flameless combustion regime

Esmaeil Ebrahimi Fordoei, Kiumars Mazaheri
Journal PapersFuel and Combustion , Volume 13 , Issue 3, 2020 September 19, {Pages 26-Jan }

Abstract

The aim of the present study is to investigate the effect of carbon dioxide injection on the flame structure using numerical simulation of flameless furnace. Using different amounts of carbon dioxide injection leads to the formation of three air-fuel, oxygen enrich and oxy-fuel combustion modes. Numerical simulations are performed using OpenFoam software. The standard k-εmodel for turbulence modeling and the discrete ordinate model for radiation modeling are used, respectively. Four combustion models based on the eddy dissipation concept model have also been used to validation of combustion model. Studies are performed on temperature distribution, ignition delay, flame color, and hydroxyl radical in order to the investigation of flame stru

Numerical investigation of adding water vapor to air of combustion in an industrial boiler

Kiumars Mazaheri, Ali Zarei
Journal PapersFuel and Combustion , Volume 13 , Issue 4, 2020 September 23, {Pages 117-138 }

Abstract

Environmental issues and air pollution have attracted a lot of attention in recent years. Thermal power plants are among the air pollutants. One of the solutions used for better combustion and less pollution in other combustion systems, including gas turbines, is the idea of water vapor injection. In this study, it was considered that with the idea of adding water vapor to the gas turbine, a similar work would be done in the boilers, for which in this research, a 11 Megawatts single axisymmetric burner in the form of two dimension is modeled using the open source software OpenFoam and the ReactingFoam solver. For simulation, the equations for mass, momentum, energy, and species conservation were solved together as a coupling, and the pressu

Chemical and Physical Effects of Carbon Dioxide Injection with Different Preheating Temperature in Flameless Combustion

Esmaeil Ebrahimi Fordoei, Kiumars Mazaheri
Journal PapersAmirkabir Journal of Mechanical Engineering , Volume 52 , Issue 2, 2020 April 20, {Pages 21-30 }

Abstract

The purpose of the present study is numerical simulation of flameless burner with carbon dioxide injection into the oxidizer stream using open-source openFoam software. Also, the effect of different amounts of oxidizer preheating temperature has been studied. In order to perform simulations from the PaSR combustion model, the standard k-ε turbulence model with modified coefficients and discrete phase radiation model with calculation of adsorption and emission coefficients using WSGGM model with non-gray gas coefficients have been used. The results of the present study indicate that the physical effects of carbon dioxide degradation will reduce the amount of heat release and the amount of carbon monoxide produced, while the chemical effects

A turbulent duct flow investigation of drag-reducing viscoelastic FENE-P fluids based on different low-Reynolds-number models

Ehsan Rasti, Farhad Talebi, Kiumars Mazaheri
Journal PapersPhysica A: Statistical Mechanics and its Applications , Volume 526 , 2019 July 15, {Pages 120718 }

Abstract

Drag reduction of viscoelastic fluids under turbulent flow regime is an important phenomenon and well observed by many researchers. In this paper, turbulent flow characteristics under drag reduction condition are compared using four different low-Reynolds number k-ε models namely, Lam–Bremhorst, Launder–Sharma, Nagano–Hishida and Chien. The viscoelastic turbulence closure of Resende et al.(2011) is adopted. Time-averaged momentum and rheological constitutive equations based on finitely extensible nonlinear elastic-Peterlin (FENE-P) model are used and a polymeric contribution to the eddy viscosity equation is considered. The simulations are conducted for two sets of rheological parameters identified by Re τ 0= 395, β= 0. 9, L 2= 900

Numerical study of chemical kinetics and radiation heat transfer characteristics on the temperature distribution in the oxy-fuel combustion

E Ebrahimi Fordoei, Kiumars Mazaheri
Journal PapersHeat and Mass Transfer , Volume 55 , 2019 July , {Pages 2025-2036 }

Abstract

In this study, The IFRF methane-oxygen combustion furnace is used to investigate the effect of the radiation model, the method of evaluated absorption and emission coefficients and the different chemical mechanisms. The simulations are performed with OpenFOAM open source software by using of PaSR (partially stirred reactor) combustion model. The numerical investigations are carried out without radiative heat transfer and with the modeling of the radiation source term using the P1 (spherical harmonic radiation model) and DO (discrete ordinate) models. To evaluate the absorption and emission coefficients used from the constant coefficients, the grey mean gases model in terms of temperature polynomial, the WSGGM (weighted sum of grey gases mod

Numerical study of chemical kinetics and radiation heat transfer characteristics on the temperature distribution in the oxy-fuel combustion

E Ebrahimi Fordoei, Kiumars Mazaheri
Journal PapersHeat and Mass Transfer , Volume 55 , Issue 7, 2019 July 1, {Pages 2025-2036 }

Abstract

In this study, The IFRF methane-oxygen combustion furnace is used to investigate the effect of the radiation model, the method of evaluated absorption and emission coefficients and the different chemical mechanisms. The simulations are performed with OpenFOAM open source software by using of PaSR (partially stirred reactor) combustion model. The numerical investigations are carried out without radiative heat transfer and with the modeling of the radiation source term using the P1 (spherical harmonic radiation model) and DO (discrete ordinate) models. To evaluate the absorption and emission coefficients used from the constant coefficients, the grey mean gases model in terms of temperature polynomial, the WSGGM (weighted sum of

Improvement of drag reduction prediction in viscoelastic pipe flows using proper low-Reynolds k-ε turbulence models

Ehsan Rasti, Farhad Talebi, Kiumars Mazaheri
Journal PapersPhysica A: Statistical Mechanics and its Applications , Volume 516 , 2019 February 15, {Pages 412-422 }

Abstract

Developing proper turbulence models in order to predict flow characteristics of viscoelastic drag-reducing fluids has become as a considerable portion of non-Newtonian flows researches. In this numerical study, three different low-Reynolds-number k-ε models namely, Launder–Sharma, Lam–Bremhorst and Malin are used based on the adopted viscoelastic turbulence closure of Cruz et al.(2004). Simulation results for friction factor, mean axial velocity, turbulent kinetic energy and Reynolds shear stress are obtained for three aqueous polymer solutions (0.3% carboxymethyl cellulose, 0.2% xanthan gum and 0.2% polyacrylamide) and validated against the corresponding experimental data. While a good agreement exists for the bulk parameters like dra

Numerical study of flame aerodynamic in rotary kilns

R Hazrati, K Mazaheri, Fordoei E Ebrahimi
Journal Papers , Volume 49 , Issue 38800442, 2019 January 1, {Pages 117-126 }

Abstract

Rotary kilns have some applications in industrial due to high production capacity, uniform and extensive combustion. Rotary kiln performance not easy and despite of technology development, the problems exist in the filed from combustion them. Reasons of some problems are separate design of burner and kiln and inattention to coordination and harmony between them. According to in the present study, flame behavior has been studied under governed condition on the kiln and secondary air flow. In the first step, suitable methods and models are verified on the basis of benchmark problem due to lack of experimental data. Finally, rotary kiln simulation done with realizable k-ε turbulence model, partially stirred reacting flow combustion model and

Noise calculation in a turbulent non-premixed flame using a hybrid analytical-LES method

KIUMARS MAZAHERI, Yasser Mahmoudi
Journal Papers , Volume 12 , Issue 300864, 2019 January 1, {Pages 107-124 }

Abstract

In the present work, the noise of a turbulent non-premixed free flame is calculated. A Hybrid method with Lighthill analogy along with a CFD simulation is used to evaluate combustion noise. In this way, the reactive flow equations are solved by the Large Eddy Simulation and Partially Stirred Reactor model to simulate the interaction of turbulence and reaction. Then the combustion noise source terms including heat release fluctuation and non-isomolar combustion are extracted and used as the sources of Lighthill analogy. The assumption of the compact flame is applied to the Lighthill equation and the Green function is used to calculate far-field pressure fluctuations. It was shown that in low and medium frequency sound pressure level is in a

Numerical Study of Carbon Dioxide Injection Effect into Oxidizer in Flameless Oxyfuel Combustion

Fordoei E Ebrahimi, K Mazaheri
Journal Papers , Volume 49 , Issue 18600440, 2019 January 1, {Pages 20-Nov }

Abstract

The aim of present study is numerical investigation of carbon dioxide injection effect on the flameless oxy-fuel combustion. For this purpose, different subjects have been analyzed such as various regimes composed in oxy-fuel combustion, temperature distribution and heat release in different values carbon dioxide injection, minimum amount of CO2 for injection in oxidizer and maximum carbon dioxide injected into oxidizer. The counter flow diffusion flame solver used to steady and axisymmetric simulations. Also, a base condition is used with preheating temperature equal 1400K to deliver results. The obtained results show that injection of carbon dioxide into the oxidizer to reduce the maximum and mean combustion temperature. In the carbon dio

Experimental analysis of blockage effect on low-swirl burner combustion parameters for lean premixed natural gas-air flames

Morteza Nahvi, Kiumars Mazaheri, Mohammad Mahdi Parsafar, Amirreza Mohammadpour
Journal PapersProceedings of 18th Fluid Dynamics Conference , 2019 August , {Pages 27-29 }

Abstract

In this paper, the effect of axial flow blockage percentage on combustion parameters of a low-swirl burner is investigated. The burner uses premixed natural gas and air mixture. Equivalence ratio varies from 0.55 to 0.59 (lean mixture). Flow patterns are compared in 51.1%, 57.8% and 67.2% of blocked area of axial flow, power of 21.7 kWs and equivalence ratio of 0.57. Geometrical aspects of flame are compared using Canny edge detection algorithm. The combustion zone temperature profile is analyzed using thermocouples in different vertical distances from the burner edge. OH* radical chemiluminescence is compared qualitatively using flame spectroscopy. The concentration of important emissions like CO, NO and NO2 are also reported using exhaust

One-dimensional Combustion Simulation for Different Hydrogen-enriched Natural Gas Blends

Ehsan Bahmani, Kiumars Mazaheri, Alireza Alipour
Journal PapersAmirkabir Journal of Mechanical Engineering , 2019 June 23, {Pages }

Abstract

Land-based gas turbines are one of the most practical turbines that use natural gas as the main fuel. Since natural gas is produced with different composition in refinery process, it can lead to change widely the combustion characteristics. Due to avoid from the effect of this undesirable variation on combustion characteristics, different methods are suggested. One of these methods is injection of Hydrogen into the main fuel (i.e. Natural gas). Hydrogen fuel has some desirable properties such as low activation energy, high reaction rate and high burning velocity which makes hydrogen as a suitable additive for the modification of combustion characteristics of hydrocarbon fuels. The main purpose of the present study is to study the effect of

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