Majid Emami Meibodi | Ardakan University (original) (raw)
Papers by Majid Emami Meibodi
International Journal of Water and Wastewater Treatment, 2016
EB irradiation is used for treatment of different wastewater including textile effluent and the d... more EB irradiation is used for treatment of different wastewater including textile effluent and the decoloration effect may be evaluated by several methods. In this work, the effect of EB irradiation on reactive dyes is investigated due to Integrated Absorbance Units (IAU) and the method developed by members of the American Dye Manufacturers Institute (ADMI). The value of pH will affect ADMI measurement at low values but its effect on high values of ADMI and decoloration due to EB irradiation is negligible. According to the results, decoloration due to EB irradiation can be reported based on the ADMI with pH adjustment, ADMI without pH adjustment and IAU data.
Radiation Physics and Chemistry, 2016
Two pilot scale reactors are designed for EB irradiation of wastewater. The doses of 1 to 3 kGy a... more Two pilot scale reactors are designed for EB irradiation of wastewater. The doses of 1 to 3 kGy are suitable for different wastewater. The synergism role of ozone treatment beside EB is investigated. The order of irradiation and coagulation is studied. Low doses of EB irradiation may result in BOD enhancement.
Biofuels, 2017
ABSTRACT In this work the optimum ratio of syngas components and the optimum temperature, pressur... more ABSTRACT In this work the optimum ratio of syngas components and the optimum temperature, pressure, equivalence ratio and moisture content for different types of biomass are investigated for methanol synthesis according to the Gibbs free energy minimization calculations. Our results show the yield of methanol synthesis may be solely determined by the ratio in long ranges of temperature, pressure, and . So, the produced syngas quality in the biomass gasification was evaluated according to the R1 parameter for 86 varieties of biomass. Herein, a new optimum temperature for the gasification process is defined and it is shown that this temperature, which is always preferred for commercial processing, is 800 and 1100 °C in 1 and 70 atm, respectively. Some of the best biomass varieties for methanol synthesis include mustard husks, tamarack bark, greenhouse-plastic waste and meat-bone meal; the first one shows the highest H2/CO ratio.
Heat and Mass Transfer, 2016
Various experimental works have been reported on boiling of nanofluids, and some contradictory da... more Various experimental works have been reported on boiling of nanofluids, and some contradictory data are reported in this case in the literature. Systematic errors in experiments may be one of the factors causing a significant gap in the data. In this paper, boiling of Ag–water nanofluid is studied empirically. A NiCr wire is used for the experiments. According to UV–Vis absorption spectra data, Ag–water nanofluid changes during the tests. Since the electrical resistance–temperature relationship for the NiCr test section changes during the experiments, the wire temperature cannot be determined by this method. This can be accounted for by the presence of a porous nanoparticle layer created through particle deposition during nucleate boiling.
Ozone: Science & Engineering, 2013
ABSTRACT In this study, the effects of ozone and electron beam radiation on color removal of dyes... more ABSTRACT In this study, the effects of ozone and electron beam radiation on color removal of dyes mixture were studied. According to the obtained results, the COD data denote that a first-irradiation process is a better one and the absorbency data denote that ozonation after irradiation will result in higher values of decolorization. Therefore, it can be said that a process that first applies an electron beam and then uses ozonation is better than the reverse process. Using a new approach for interpretation of the experimental decolorization results, it has been shown that the calculated dye removal percentages based on ozone consumption are near to experimental decolorization results.
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2021
The correct information on RTD can help in system design and evaluation. The RTD corresponding to... more The correct information on RTD can help in system design and evaluation. The RTD corresponding to the velocity profile is known only for certain cases, where the velocity profile depends on one coordinate only. In this research, a general procedure for derivation of RTD corresponding to a known velocity profile is introduced. The RTD of laminar flows in different ducts as elliptic, equilateral triangular, moon-shaped and rectangular ducts are derived. Also, it is shown that the final RTD for laminar flow in any duct, can be estimated using relation E(θ) = K θmin/θn that is similar to laminar flow in the pipe, with their own dimensionless minimum time, , where is defined as the required time for traveling the duct with the maximum velocity in unit of the space-time. The values of K and n is calculated to meet the condition of . Besides, the values of for different cross-sections are studied. The results show that the RTD of elliptic ducts is precisely similar to the pipe flow. In the...
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2020
The famous definition of RTD is based on the volumetric flow rate but is experimentally defined u... more The famous definition of RTD is based on the volumetric flow rate but is experimentally defined using the tracer concentration. These different views have erroneously limited the application of the velocity profile for RTD evaluation to the laminar flows. In this work, a more general sense of RTD is introduced and it has been emphasized that regardless of the dispersion behavior, the velocity profile is sufficient in order to obtain the corresponding RTD. A general algorithm for RTD evaluation using axial velocity profile is developed and the relations were derived for different systems. In addition, the corresponding velocity profiles to the famous RTD models were numerically evaluated. It has been shown that the final forms are consistent compared to the previous relations for laminar flows.
Chemical Engineering Transactions, 2018
The purpose of this study was to investigate heat transfer performance of a wavy micro channels h... more The purpose of this study was to investigate heat transfer performance of a wavy micro channels heat exchanger with a new nanofluid. Nonporous graphene in an aqueous solution containing 0.2 wt.% carboxyl methyl cellulose (CMC) were used as base hot fluid. In preparation of non-Newtonian nanofluids by using properties of the base fluid, Gum Arabic, Tween 80, CTAB, Triton X100, and Acumer 300 were used as surfactants. The Results show that 1- as flowrate, relative waviness (2A/2L) and concentration of NPG increase the convective heat transfer coefficient could be intensified. 2- it was seen that with increasing the flowrate and relative waviness (2A/2L) the pressure drop was intensified. The impacts of the obtained results are introducing a new method to enhance heat transfer. In addition, a new definition for comprehensive performance of heat exchangers is introduced and used to evaluate the feasibility of the proposed system.
Energy Conversion and Management, 2014
ABSTRACT In the present study an experimental investigation was carried out in order to find the ... more ABSTRACT In the present study an experimental investigation was carried out in order to find the role of the conical rings for the heat transfer enhancement and pressure drop change in a pipe with constant heat flux boundary condition. The conical rings were placed in two different arrangements: converging conical ring (CR array) and diverging conical ring (DR array). Also numerical study was performed through Computational Fluid Dynamics (CFD) calculations. The CFD predictions show suitable agreement with the experimental data of Nusselt number but overestimate pressure drop values. The predictions and the experimental results show that in the case of water as working fluid (despite air as working fluid), the conical ring inserts have an unfavorable effect on the enhancement efficiency of the heat-transfer in the heat exchangers.
Journal of Experimental Nanoscience, 2009
Thermal conductivity enhancements in aqueous media in the presence of carbon nanotubes (SWNTs) ar... more Thermal conductivity enhancements in aqueous media in the presence of carbon nanotubes (SWNTs) are investigated. The SWNTs nanofluids are prepared using a two-step method. The concentration of SWNTs suspensions is below 1 wt%. The thermal conductivities of the SWNTs suspensions are measured by a modified transient hot wire method (KD2 thermal property meter). Zeta potential, turbidity measurements and sedimentation photographs
International Communications in Heat and Mass Transfer, 2010
... a Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran. b Nanotechnol... more ... a Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran. b Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran, Iran. c Nuclear Science and Technology Research ...
International Communications in Heat and Mass Transfer, 2010
In this research, the convective heat transfer coefficients of water-based FMWNT nanofluid have b... more In this research, the convective heat transfer coefficients of water-based FMWNT nanofluid have been measured under both laminar and turbulent regimes flowing through a uniformly heated horizontal tube in entrance region. For the first time, we have compared effective parameters to measure the convective heat transfer coefficients for functionalized MWNT suspensions such as Re, mass fraction and temperature, altogether in entrance region. The experimental results indicate that the convective heat transfer coefficient of these nanofluids increases by up to 33–40% at a concentration of 0.25wt.% compared with that of pure water in laminar and turbulent flows respectively and 20°C.
International Communications in Heat and Mass Transfer, 2010
Theoretically convective heat transfer coefficient depends on velocity and temperature profiles. ... more Theoretically convective heat transfer coefficient depends on velocity and temperature profiles. In this work friction factor and convection coefficient are used in order to compare both profiles for nanofluids and base fluids. For this purpose Al2O3/water (due to its ...
International Communications in Heat and Mass Transfer, 2011
In this research, the pristine CNTs sample synthesized by the CCVD method contains catalytic part... more In this research, the pristine CNTs sample synthesized by the CCVD method contains catalytic particles and the carbonaceous impurities, and then the special purification procedure was done. By different methods CNT functionalized with various concentration ...
International Communications in Heat and Mass Transfer, 2010
The Canadian Journal of Chemical Engineering, 2008
where ω' is the monomeric acentric factor. An association equation of state (AEOS) has been propo... more where ω' is the monomeric acentric factor. An association equation of state (AEOS) has been proposed for hydrogen-bonded compounds. To obtain this AEOS, the compressibility factor was assumed to consist of two parts: the physical part due to physical interactions of molecules; and the chemical part due to molecular association by hydrogen bonding of molecules. The physical part of the compressibility factor was represented by the MMM EOS for non-polar compounds proposed by Mohsen-Nia et al., Fluid Phase Equilib. 206, 27-39 (2003), and the chemical part of the compressibility factor was deduced by proposing a molecular association model of infi nite series. On propose une équation d'état d'association (AEOS) pour les composés possédant une liaison hydrogène. Pour obtenir cette AEOS, on suppose que le facteur de compressibilité comporte deux parties: la partie physique due aux interactions physiques de molécules; et la partie chimique due à l'association moléculaire par liaison hydrogène des molécules. La partie physique du facteur de compressibilité est représentée par la MMM EOS pour composés non polaires proposée par Mohsen-Nia et al., dans Fluid Phase Equilib. 206, 27-39 (2003), et la partie chimique du facteur de compressibilité est déduit en proposant une modèle d'association moléculaire de séries infi nies.
Materials Chemistry and Physics, 2010
Various mechanisms and correlations have been developed for prediction of thermal conductivity of... more Various mechanisms and correlations have been developed for prediction of thermal conductivity of nanofluids. In this work, a simple equation has been proposed for prediction of thermal conductivity of all suspensions, including suspensions containing ...
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2021
In this research, the heat transfer behavior of a wavy mini channel heat exchanger was studied. U... more In this research, the heat transfer behavior of a wavy mini channel heat exchanger was studied. Using the experimental data of heat transfer, the convective heat transfer coefficients were estimated. Among numerous trails, Nusselt number (Nu) best correlation is a linear function of Reynolds number (Re) independent of Prandtl number (Pr), and the similar correlations for hot and cold sides were obtained. The coefficient range is 0.01 to 0.03 for different fluids. The previous experimental works verify this conclusion. Also, in the case of non-Newtonian fluids and nanofluids, the definition of Re is related to its rheological behavior. However, if the velocity profile is specified, it can be used to derive the relation between the Fanning friction factor (Cf) and Re. Here, a suitable velocity profile for wavy configuration is used and the experimental values of Re are estimated by the experimental pressure drop data. It is shown that the application of the derived relation between Cf...
International Journal of Water and Wastewater Treatment, 2016
EB irradiation is used for treatment of different wastewater including textile effluent and the d... more EB irradiation is used for treatment of different wastewater including textile effluent and the decoloration effect may be evaluated by several methods. In this work, the effect of EB irradiation on reactive dyes is investigated due to Integrated Absorbance Units (IAU) and the method developed by members of the American Dye Manufacturers Institute (ADMI). The value of pH will affect ADMI measurement at low values but its effect on high values of ADMI and decoloration due to EB irradiation is negligible. According to the results, decoloration due to EB irradiation can be reported based on the ADMI with pH adjustment, ADMI without pH adjustment and IAU data.
Radiation Physics and Chemistry, 2016
Two pilot scale reactors are designed for EB irradiation of wastewater. The doses of 1 to 3 kGy a... more Two pilot scale reactors are designed for EB irradiation of wastewater. The doses of 1 to 3 kGy are suitable for different wastewater. The synergism role of ozone treatment beside EB is investigated. The order of irradiation and coagulation is studied. Low doses of EB irradiation may result in BOD enhancement.
Biofuels, 2017
ABSTRACT In this work the optimum ratio of syngas components and the optimum temperature, pressur... more ABSTRACT In this work the optimum ratio of syngas components and the optimum temperature, pressure, equivalence ratio and moisture content for different types of biomass are investigated for methanol synthesis according to the Gibbs free energy minimization calculations. Our results show the yield of methanol synthesis may be solely determined by the ratio in long ranges of temperature, pressure, and . So, the produced syngas quality in the biomass gasification was evaluated according to the R1 parameter for 86 varieties of biomass. Herein, a new optimum temperature for the gasification process is defined and it is shown that this temperature, which is always preferred for commercial processing, is 800 and 1100 °C in 1 and 70 atm, respectively. Some of the best biomass varieties for methanol synthesis include mustard husks, tamarack bark, greenhouse-plastic waste and meat-bone meal; the first one shows the highest H2/CO ratio.
Heat and Mass Transfer, 2016
Various experimental works have been reported on boiling of nanofluids, and some contradictory da... more Various experimental works have been reported on boiling of nanofluids, and some contradictory data are reported in this case in the literature. Systematic errors in experiments may be one of the factors causing a significant gap in the data. In this paper, boiling of Ag–water nanofluid is studied empirically. A NiCr wire is used for the experiments. According to UV–Vis absorption spectra data, Ag–water nanofluid changes during the tests. Since the electrical resistance–temperature relationship for the NiCr test section changes during the experiments, the wire temperature cannot be determined by this method. This can be accounted for by the presence of a porous nanoparticle layer created through particle deposition during nucleate boiling.
Ozone: Science & Engineering, 2013
ABSTRACT In this study, the effects of ozone and electron beam radiation on color removal of dyes... more ABSTRACT In this study, the effects of ozone and electron beam radiation on color removal of dyes mixture were studied. According to the obtained results, the COD data denote that a first-irradiation process is a better one and the absorbency data denote that ozonation after irradiation will result in higher values of decolorization. Therefore, it can be said that a process that first applies an electron beam and then uses ozonation is better than the reverse process. Using a new approach for interpretation of the experimental decolorization results, it has been shown that the calculated dye removal percentages based on ozone consumption are near to experimental decolorization results.
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2021
The correct information on RTD can help in system design and evaluation. The RTD corresponding to... more The correct information on RTD can help in system design and evaluation. The RTD corresponding to the velocity profile is known only for certain cases, where the velocity profile depends on one coordinate only. In this research, a general procedure for derivation of RTD corresponding to a known velocity profile is introduced. The RTD of laminar flows in different ducts as elliptic, equilateral triangular, moon-shaped and rectangular ducts are derived. Also, it is shown that the final RTD for laminar flow in any duct, can be estimated using relation E(θ) = K θmin/θn that is similar to laminar flow in the pipe, with their own dimensionless minimum time, , where is defined as the required time for traveling the duct with the maximum velocity in unit of the space-time. The values of K and n is calculated to meet the condition of . Besides, the values of for different cross-sections are studied. The results show that the RTD of elliptic ducts is precisely similar to the pipe flow. In the...
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2020
The famous definition of RTD is based on the volumetric flow rate but is experimentally defined u... more The famous definition of RTD is based on the volumetric flow rate but is experimentally defined using the tracer concentration. These different views have erroneously limited the application of the velocity profile for RTD evaluation to the laminar flows. In this work, a more general sense of RTD is introduced and it has been emphasized that regardless of the dispersion behavior, the velocity profile is sufficient in order to obtain the corresponding RTD. A general algorithm for RTD evaluation using axial velocity profile is developed and the relations were derived for different systems. In addition, the corresponding velocity profiles to the famous RTD models were numerically evaluated. It has been shown that the final forms are consistent compared to the previous relations for laminar flows.
Chemical Engineering Transactions, 2018
The purpose of this study was to investigate heat transfer performance of a wavy micro channels h... more The purpose of this study was to investigate heat transfer performance of a wavy micro channels heat exchanger with a new nanofluid. Nonporous graphene in an aqueous solution containing 0.2 wt.% carboxyl methyl cellulose (CMC) were used as base hot fluid. In preparation of non-Newtonian nanofluids by using properties of the base fluid, Gum Arabic, Tween 80, CTAB, Triton X100, and Acumer 300 were used as surfactants. The Results show that 1- as flowrate, relative waviness (2A/2L) and concentration of NPG increase the convective heat transfer coefficient could be intensified. 2- it was seen that with increasing the flowrate and relative waviness (2A/2L) the pressure drop was intensified. The impacts of the obtained results are introducing a new method to enhance heat transfer. In addition, a new definition for comprehensive performance of heat exchangers is introduced and used to evaluate the feasibility of the proposed system.
Energy Conversion and Management, 2014
ABSTRACT In the present study an experimental investigation was carried out in order to find the ... more ABSTRACT In the present study an experimental investigation was carried out in order to find the role of the conical rings for the heat transfer enhancement and pressure drop change in a pipe with constant heat flux boundary condition. The conical rings were placed in two different arrangements: converging conical ring (CR array) and diverging conical ring (DR array). Also numerical study was performed through Computational Fluid Dynamics (CFD) calculations. The CFD predictions show suitable agreement with the experimental data of Nusselt number but overestimate pressure drop values. The predictions and the experimental results show that in the case of water as working fluid (despite air as working fluid), the conical ring inserts have an unfavorable effect on the enhancement efficiency of the heat-transfer in the heat exchangers.
Journal of Experimental Nanoscience, 2009
Thermal conductivity enhancements in aqueous media in the presence of carbon nanotubes (SWNTs) ar... more Thermal conductivity enhancements in aqueous media in the presence of carbon nanotubes (SWNTs) are investigated. The SWNTs nanofluids are prepared using a two-step method. The concentration of SWNTs suspensions is below 1 wt%. The thermal conductivities of the SWNTs suspensions are measured by a modified transient hot wire method (KD2 thermal property meter). Zeta potential, turbidity measurements and sedimentation photographs
International Communications in Heat and Mass Transfer, 2010
... a Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran. b Nanotechnol... more ... a Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran. b Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran, Iran. c Nuclear Science and Technology Research ...
International Communications in Heat and Mass Transfer, 2010
In this research, the convective heat transfer coefficients of water-based FMWNT nanofluid have b... more In this research, the convective heat transfer coefficients of water-based FMWNT nanofluid have been measured under both laminar and turbulent regimes flowing through a uniformly heated horizontal tube in entrance region. For the first time, we have compared effective parameters to measure the convective heat transfer coefficients for functionalized MWNT suspensions such as Re, mass fraction and temperature, altogether in entrance region. The experimental results indicate that the convective heat transfer coefficient of these nanofluids increases by up to 33–40% at a concentration of 0.25wt.% compared with that of pure water in laminar and turbulent flows respectively and 20°C.
International Communications in Heat and Mass Transfer, 2010
Theoretically convective heat transfer coefficient depends on velocity and temperature profiles. ... more Theoretically convective heat transfer coefficient depends on velocity and temperature profiles. In this work friction factor and convection coefficient are used in order to compare both profiles for nanofluids and base fluids. For this purpose Al2O3/water (due to its ...
International Communications in Heat and Mass Transfer, 2011
In this research, the pristine CNTs sample synthesized by the CCVD method contains catalytic part... more In this research, the pristine CNTs sample synthesized by the CCVD method contains catalytic particles and the carbonaceous impurities, and then the special purification procedure was done. By different methods CNT functionalized with various concentration ...
International Communications in Heat and Mass Transfer, 2010
The Canadian Journal of Chemical Engineering, 2008
where ω' is the monomeric acentric factor. An association equation of state (AEOS) has been propo... more where ω' is the monomeric acentric factor. An association equation of state (AEOS) has been proposed for hydrogen-bonded compounds. To obtain this AEOS, the compressibility factor was assumed to consist of two parts: the physical part due to physical interactions of molecules; and the chemical part due to molecular association by hydrogen bonding of molecules. The physical part of the compressibility factor was represented by the MMM EOS for non-polar compounds proposed by Mohsen-Nia et al., Fluid Phase Equilib. 206, 27-39 (2003), and the chemical part of the compressibility factor was deduced by proposing a molecular association model of infi nite series. On propose une équation d'état d'association (AEOS) pour les composés possédant une liaison hydrogène. Pour obtenir cette AEOS, on suppose que le facteur de compressibilité comporte deux parties: la partie physique due aux interactions physiques de molécules; et la partie chimique due à l'association moléculaire par liaison hydrogène des molécules. La partie physique du facteur de compressibilité est représentée par la MMM EOS pour composés non polaires proposée par Mohsen-Nia et al., dans Fluid Phase Equilib. 206, 27-39 (2003), et la partie chimique du facteur de compressibilité est déduit en proposant une modèle d'association moléculaire de séries infi nies.
Materials Chemistry and Physics, 2010
Various mechanisms and correlations have been developed for prediction of thermal conductivity of... more Various mechanisms and correlations have been developed for prediction of thermal conductivity of nanofluids. In this work, a simple equation has been proposed for prediction of thermal conductivity of all suspensions, including suspensions containing ...
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2021
In this research, the heat transfer behavior of a wavy mini channel heat exchanger was studied. U... more In this research, the heat transfer behavior of a wavy mini channel heat exchanger was studied. Using the experimental data of heat transfer, the convective heat transfer coefficients were estimated. Among numerous trails, Nusselt number (Nu) best correlation is a linear function of Reynolds number (Re) independent of Prandtl number (Pr), and the similar correlations for hot and cold sides were obtained. The coefficient range is 0.01 to 0.03 for different fluids. The previous experimental works verify this conclusion. Also, in the case of non-Newtonian fluids and nanofluids, the definition of Re is related to its rheological behavior. However, if the velocity profile is specified, it can be used to derive the relation between the Fanning friction factor (Cf) and Re. Here, a suitable velocity profile for wavy configuration is used and the experimental values of Re are estimated by the experimental pressure drop data. It is shown that the application of the derived relation between Cf...