Radiation Absorption Effects Research Articles

Effect of radiation absorption and buoyancy force on the MHD mixed convection flow of Casson nanofluid embedded with Al50Cu50 alloy nanoparticles

Purpose The purpose of this paper is to report the effects of radiation absorption and buoyancy forces on the boundary layer analysis of Casson nanofluid past a vertical plate in a porous enclosure filled with Al50Cu50 alloy nanoparticles. Design/methodology/approach The authors reconstructed the controlling equations as a group of nonlinear ODEs and solved analytically using perturbation technique. The vital interest in this analysis is to examine the influence of sundry physical parameters on the common profiles (velocity, temperature and concentration) conferred through the plots. Tabular values are listed to discuss the skin friction factor, heat and mass transfer rates. Dual solutions are observed for Newtonian and non-Newtonian fluid cases. Findings Acquired results indicate that the Casson fluid plays a major role in controlling heat and mass transfer rates as compared with Newtonian fluid. Also, raise in volume fraction of nanoparticles regulates the thermal fields, discerns the velocity fields. The authors established the comparison of present results with previously published results and they are found in good agreement for limited cases. Originality/value Because of the substantial properties of aluminium and its alloys such as, extreme corrosion resistance, exalted electrical and thermal conductivities and ease of fabrication they achieved tremendous applications in transportation especially in space and aircrafts, in the production of electrical transmission lines. In view of these, the current literature is perpetrated to probe the impact of radiation absorption and buoyancy forces on the heat and mass transfer analysis of Casson nanofluid in the presence of Al50Cu50 alloy nanoparticles.

Radiation Absorption and Chemical Reaction Effects on MHD Flow through Porous Medium Past an Exponentially Accelerated Inclined Plate

Radiation Absorption and Chemical Reaction Effects on MHD Flow through Porous Medium Past an Exponentially Accelerated Inclined Plate

HEAT AND MASS TRANSFER ON MHD FLUID FLOW OVER A SEMI INFINITE FLAT PLATE WITH RADIATION ABSORPTION, HEAT SOURCE AND DIFFUSION THERMO EFFECT

HEAT AND MASS TRANSFER ON MHD FLUID FLOW OVER A SEMI INFINITE FLAT PLATE WITH RADIATION ABSORPTION, HEAT SOURCE AND DIFFUSION THERMO EFFECT

Chemically reactive and naturally convective high speed MHD fluid flow through an oscillatory vertical porous plate with heat and radiation absorption effect

This paper concerns with the modelling of an unsteady natural convective and higher order chemically reactive magnetohydrodynamics (MHD) fluid flow with the effect of heat and radiation absorption. The flow is generated through a vertical oscillating porous plate. Boundary layer approximations is carried out to establish a flow model which represents the time dependent momentum, energy and diffusion balance equations. Before being solved numerically, the governing partial differential equations (PDEs) were transformed into a set of nonlinear ordinary differential equation (ODEs) by using non-similar technique. A very efficient numerical approach solves the obtained nonlinear coupled ODEs so called Explicit Finite Difference Method (EFDM). An algorithm is implemented in Compaq Visual Fortran 6.6a as a solving tool. In addition, the stability and convergence analysis (SCA) is examined and shown explicitly. The advantages of SCA is its optimizes the accuracy of system parameters such as Prandtl number (Pr) and Schmidt number (Sc).The velocity, temperature and concentration fields in the boundary layer region are studied in detail and the outcomes are shown in graphically with the influence of various pertinent parameters such as Grashof number (Gr), modified Grashof number (Gr), magnetic parameter (M), Darcy number (Da),Prandtl number (Pr), Schmidt number (Sc), radiation (R), heat sink (Q),radiation absorption (Q1), Eckert number (Ec), Dufour number (Du),Soret number (Sr), Schmidt number (Sc), reaction index (P) and chemical reaction (Kr). Furthermore, the effect of skin friction coefficient (Cf), Nusselt number (Nu) and Sherwood number (Sh) are also examined graphically.

Joule Heating and Radiation Absorption Effects on MHD Convective and Chemically Reactive Flow past a Porous Plate

Joule Heating and Radiation Absorption Effects on MHD Convective and Chemically Reactive Flow past a Porous Plate

Radiation absorption and viscous dissipation effects on MHD free convection flow of Casson fluid past a semi-infinite moving vertical porous plate

Radiation absorption and viscous dissipation effects on MHD free convection flow of Casson fluid past a semi-infinite moving vertical porous plate

Thermal Radiation and Heat Absorption Effect on Heat and Mass Transfer over an Exponential Stretching Porous Surface with Viscous Dissipation

Thermal Radiation and Heat Absorption Effect on Heat and Mass Transfer over an Exponential Stretching Porous Surface with Viscous Dissipation

Radiation Absorption and Viscous-Dissipation on MHD Flow of Casson Fluid over a Vertical Plate Filled with Porous Layers

The present study aims to analyze the radiation absorption and viscous dissipation effects on MHD free convective Casson fluid flow over a vertical permeable semi-infinite plate in the presence of first order homogeneous chemical reaction. The time-dependent wall suction is assumed to occur at the permeable surface. The non-Newtonian fluid behavior is characterized by using the Casson fluid model. The coupled non-linear ordinary differential equations (ODE’s) are solved by perturbation technique. The impact of sundry parameters on the velocity, temperature, species concentration as well as the friction factor coefficient, the rate of heat and mass transfer coefficients are computed and analyzed through graphs.

Effects of radiation on large-scale spherical flame propagation

One-dimensional numerical simulations are conducted for large-scale spherical flame propagation in near-stoichiometric methane/air mixture. With the help of adaptive mesh refinement, we simulate the spherical flame propagation up to a radius of 4m inside an extremely large computational domain of 20m. The emphasis is placed on quantifying the radiation effects on large-scale spherical flame propagation. Besides the adiabatic model neglecting radiative loss, two radiation models are used in simulation: one is the optically thin model considering only radiation emission and the other is the statistical narrow band model considering both radiation emission and absorption. The effects of radiative loss and radiation absorption on large-scale spherical flame propagation are quantified through comparison among results predicted by these three models. It is shown that for the near stoichiometric methane/air mixture, radiation has little influence on small-scale spherical flame propagation with radius below 4cm; while radiative loss and radiation absorption both have great impact on large-scale spherical flame propagation with radius up to 4m. Spherical flames without and with self-acceleration are both considered in 1D simulation. Radiation effects on the propagation speed and acceleration exponent of the large-scale self-accelerating spherical flame are assessed. It is found that radiation effects on acceleration exponent are exaggerated when radiation absorption is neglected. In experiments for large-scale spherical flame propagation, the acceleration exponent is not strongly affected by radiation due to radiation absorption.

Investigations on SAR and Thermal Effects of a Body Wearable Microstrip Antenna

Wearable technology has emerged as a hot topic in contemporary years around the globe and the interest in this sector continues to develop and will dominate in the future as well. This research work presents a microstrip-based multi-band monopole antenna for body wearable wireless devices (WWD) used for various body centric wireless communication applications. The designed antenna works at multi bands resonating at 1.8, 2.4, 5.0 and 8.9 GHz covering wireless and UWB based communication technologies. The electromagnetic (EM) effects of radiation absorption are investigated in terms of specific absorption rate and its biological manifestation as heating effect. EM computations and measurements are used to analyze the biological effects when placed on different sites on the body. Thermal effects for short term exposures and steady state conditions are evaluated using analytical methods. Experimental techniques using infrared thermography has been used for finding out the temperature elevation at three specific regions of the body. Simulated, analytical and experimental results of the heating effect are compared and are in good agreement. Further, the rise in temperature is found to be compliant with international safety regulations.

Unsteady Magnetohydrodynamic Mixed Convection Flow of Micropolar Fluid Past a Permeable Sphere

In this paper, the flow and heat transfer characteristics for unsteady mixed convection flow of an electrically conducting micropolar fluid past a permeable sphere are investigated in detail. The effects of thermal radiation and heat generation or absorption are also considered. The governing equations are transformed into nonlinear ordinary differential equations using new coordinate transformations. Solutions are obtained by employing an implicit finite difference method. Numerical results can predict the boundary-layer characteristics even after the point of boundary-layer separation. The remarkable findings are that the mixed convection parameter and the fluid suction through the porous wall considerably enhance the friction factor, couple stress, and Nusselt number; whereas they are found to decrease with the magnetic field parameter and the fluid injection. Due to an increase of the heat generation parameter and the conduction–radiation parameter, the friction factor and the couple stress increase but the Nusselt number decreases. However, the heat absorption parameter leads to the converse characteristics.

Radiation Absorption Effects on Unsteady MHD Flow of Radiative and Chemically Reacting Fluid Past a Porous Plate with Variable Suction and Concentration

Radiation Absorption Effects on Unsteady MHD Flow of Radiative and Chemically Reacting Fluid Past a Porous Plate with Variable Suction and Concentration

Radiation Absorption and Variable Electrical Conductivity Effect on High Speed MHD Free Convective Flow past an Exponential Accelerated Inclined Plate

The effects of variable electrical conductivity and radiation absorption on high-speed MHD (Magnetohydrodynamics) free convective flow past an exponential accelerated inclined plate with higher order chemical reaction have been investigated. The electrical conductivity has been considered as a function of temperature. The chemical reaction has also been considered as the higher order. The usual transformations have been used to obtain the coupled dimensionless momentum, energy and concentration equations. Then the obtained non-dimensional partial differential equations have been solved numerically by explicit finite difference method. For excellent accuracy, stability and convergence test have been carried out. A computer program Compaq Visual FORTRAN 6.6a has been used to calculate the numerical results. The obtained numerical results concerned with the fluid velocity, temperature, concentration, concerned with skin friction, Nusselt number, Sherwood number, streamlines and isotherms are imprinted graphically by Tecplot and discussed in details. It is noticed that increasing of magnetic parameter increases the temperature and decreases the velocity, skin friction and Nusselt number. It is also observed that the temperature profile is increasing with the increasing values of Dufour number. However, the order of the chemical reaction increases the concentration profile.

Влияние поглощения лазерного излучения на эффективность лазерной сварки меди и ее сплавов

Влияние поглощения лазерного излучения на эффективность лазерной сварки меди и ее сплавов

Effect of laser radiation absorption on efficiency of laser welding of copper and its alloys

Effect of laser radiation absorption on efficiency of laser welding of copper and its alloys

Radiometric Characteristics of KOMPSAT-3 Multispectral Images Using the Spectra of Well-Known Surface Tarps

A vicarious calibration with reference to characterized surface tarps was conducted to determine the first radiometric characteristics of KOMPSAT-3. The 6S radiative transfer model was also used by inputting various initial parameters, such as the spectral response function of KOMPSAT-3, and atmospheric and geometric conditions. Moderate-Resolution Imaging Spectroradiometer atmospheric products, such as aerosol optical depth, precipitable water, and total ozone, were used as input parameters to interpret solar radiation reflection, scattering, and absorption effects. In the first field campaign, the radiometric coefficients from each of the spectral bands were estimated by calculating the predicted radiance at sensor level and the digital number (DN) of KOMPSAT-3 based on a linear least squares fit over a range of target reflectance levels. The second field campaign measurements were also used to upgrade the KOMPSAT-3 DNs to radiance coefficients. The root-mean-square error differences between simulated radiance and measured radiance during the second field campaign for “sensor-to-itself” calibration were 2.072 W/m 2 sr (blue), 6.80 W/m 2 sr (green), 7.512 W/m 2 sr (NIR), and 5.712 W/m 2 sr (red), respectively. This highlights that radiometric calibration with tarps is a reliable method. Furthermore, the gain ratio between the first and the second one was <; 5%, indicating reasonable radiometric calibration results. Additionally, cross-validation of KOMPSAT-3 with radiometrically well-calibrated Landsat-8 was performed over bright desert. Although the difference between the vicarious calibration with surface tarps and cross-validation with Landsat-8 was significant, reasonable results were obtained under close geometrical conditions, despite inherent vicarious calibration error.

Unsteady MHD Free Convection Flow Characteristics of a Viscoelastic Fluid Past a Vertical Porous Plate

ABSTRACT The present study considers an analytical investigation of unsteady MHD freeThe present study considers an analytical investigation of unsteady MHD freeconvection flow of a viscoelastic, incompressible, electrically conducting fluid past a verticalporous plate through a porous medium with time dependent oscillatory permeability and suctionin presence of a uniform transverse magnetic field. Then effects of radiation, heat generation/absorption, radiation absorption and homogeneous chemical reaction are c onsidered. The noveltyof the present study is to analyze the effect of time dependent fluctuate suction and permeabilityof the medium on a viscoelastic fluid flow in the presence of radiation, heat generation/ absorption,radiation absorption and chemica l reaction. The coupled nonlinear partial differential equationsare turned to ordinary by super imposing solutions with steady and time dependent transient part.Finally, the set of ordinary differential equations are solved with a perturbation scheme to meet theinadequacy of boundary condition. Elasticity of the fluid and the Lorentz force reduce the velocityand it is more pronounced in case of heavier species. Most interesting observation is the fluctuationof velocity appears near the plate due to the presence of sink and presences of elastic element aswell as heat source reduce the skin friction.

FESTR: Finite-Element Spectral Transfer of Radiation spectroscopic modeling and analysis code

We report on the development of a new spectral postprocessor of hydrodynamic simulations of hot, dense plasmas. Based on given time histories of one-, two-, and three-dimensional spatial distributions of materials, and their local temperature and density conditions, spectroscopically-resolved signals are computed. The effects of radiation emission and absorption by the plasma on the emergent spectra are simultaneously taken into account. This program can also be used independently of hydrodynamic calculations to analyze available experimental data with the goal of inferring plasma conditions. Program summaryProgram title: FESTRCatalogue identifier: AFAR_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFAR_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: BSD 3-Clause licenseNo. of lines in distributed program, including test data, etc.: 1237516No. of bytes in distributed program, including test data, etc.: 17542918Distribution format: tar.gzProgramming language: C++.Computer: HPC, PC.Operating system: Linux, MacOS.RAM: Problem dependent (based on size of input)Classification: 1.3, 2.2, 20.2.Nature of problem:Calculation of spectral signals by postprocessing hydrodynamics simulations. Analysis of experimental spectroscopic data to infer plasma temperature and density conditions, and its chemical composition. Simultaneous treatment of spatial non-uniformity (on 3D unstructured meshes) along with spectroscopic-quality radiation transport.Solution method:Rays are cast across a 3D unstructured mesh that characterizes local temperature, density, and chemical composition of the material. Analytic solution to the 1D (along the ray) steady-state, local radiation transport equation is repeatedly used to gradually build a synthetic spectrum for each ray.Restrictions:Steady-state approximation of the radiation transport equation is used. Scattering as a radiation source is not included. Given plasma conditions are considered fixed; potential feedback of computed radiation back into plasma temperature and equation-of-state is neglected. Doppler shifts are not modeled at this time. The quality of the computed results critically depends on the accuracy of external atomic databases used as input by FESTR. Polygon objects are assumed to be convex at present.Running time:Problem dependent (based on size of input)—the suite of 1190 enclosed unit tests runs in less than a minute on most tested platforms.

Heat and mass transfer analysis for the MHD flow of nanofluid with radiation absorption

Abstract In this paper the effects of Diffusion thermo, radiation absorption and chemical reaction on MHD free convective heat and mass transfer flow of a nanofluid bounded by a semi-infinite flat plate are analyzed. The plate is moved with a constant velocity U 0 , temperature and the concentration are assumed to be fluctuating with time harmonically from a constant mean at the plate. The analytical solutions of the boundary layer equations are assumed of oscillatory type and are solved by using the small perturbation technique. Two types of nanofluids namely Cu-water nanofluid and TiO2-water nanofluid are used. The effects of various fluid flow parameters are discussed through graphs and tables. It is observed that the diffusion thermo parameter/radiation absorption parameter enhance the velocity, temperature and skin friction. This enhancement is very significant for copper nanoparticles. This is due to the high conductivity of the solid particles of Cu than those of TiO2. Also it is noticed that the solutal boundary layer thickness decreases with an increase in chemical reaction parameter. It is because chemical molecular diffusivity reduces for higher values of Kr.

Effects of radiation absorption on spherical flame propagation and radiation-induced uncertainty in laminar flame speed measurement

Outwardly propagating spherical flames are popularly used to measure the laminar flame speed, especially for high pressure conditions. Since radiation always exists in spherical flame experiments, the accuracy of laminar flame speed measurement is inherently affected by radiation. In this study, the radiation-induced uncertainty in laminar flame speed measurement was investigated numerically. We focused on CO2 diluted mixtures in which the radiation absorption effects are important. The outwardly propagating spherical flames of different CO2 diluted mixtures at a broad range of pressure up to 25atm were simulated. Different fuels (hydrogen, methane, dimethyl ether and iso-octane) with different amounts of CO2 dilution were considered and detailed chemistry was included in simulation. Two radiation models were used: one is the optically thin model considering only radiation emission and the other is the statistical narrow band model considering both radiation emission and absorption. The effects of radiation absorption on spherical flame propagation and radiation-induced uncertainty in laminar flame speed measurement were quantified through comparison among results predicted by these two radiation models. It was found that for CO2 diluted mixtures, radiation absorption has great impact on spherical flame propagation: it greatly reduces the radiation-induced thermal and flow effects. The influence of radiation absorption was show to be stronger at higher pressure. When only radiation emission is considered and radiation absorption is neglected, the radiation-induced uncertainty in laminar flame speed measurement is substantially over-predicted for CO2 diluted mixtures. When radiation absorption is included, the radiation-induced uncertainty in laminar flame speed measurement is nearly negligible (within 2.5%) for all the CO2 diluted mixtures considered in this study.