Mechanical improvement in solar aircraft by using tangent hyperbolic single-phase nanofluid

2021 ◽  
pp. 095440892110593
Author(s):  
Syed M. Hussain ◽  
Wasim Jamshed ◽  
Esra Karatas Akgül ◽  
Nor Ain Azeany Mohd Nasir
Keyword(s):  
Solar Radiation ◽  
Thermal Radiation ◽  
Thermal Conductance ◽  
Solid Particles ◽  
Engine Oil ◽  
Heat Transmission ◽  
Surface Drag ◽  
Aircraft Wings ◽  
Thermal Transfer ◽  
Energy Equations

Solar power is the primary thermal energy source from the sunlight. This research has carried out the study of solar aircraft with solar radiation in enhancing efficiency. The thermal transfer inside the solar aircraft wings using a nanofluid past a parabolic surface trough collector (PTSC) is investigated thoroughly. The source of heat is regarded as solar radiation. For several impacts, such as porous medium, thermal radiation, and varying heat conductivity, the heat transmission performance of the wings is examined. By using the tangent hyperbolic nanofluid (THNF), the entropy analysis has been performed. The modeled momentum and energy equations are managed using the well-established numerical methodology known as the finite difference method. Two distinct kinds of nano solid-particles have been examined, such as Copper (Cu) and Zirconium dioxide (ZrO2), while Engine Oil (EO) being regarded as a based fluid. Different diagram parameters will be reviewed and revealed as figures and tables on speed, shear stress, temperature, and the surface drag coefficient and Nüselt number. It is observed that in terms of heat transfer for amplification of thermal radiation and changeable thermal conductance parameters, the performance of the aircraft wings raises. In contrast to traditional fluid, nanofluid is the best source of heat transmission. Cu-EO's thermal efficiency over ZrO2-EG falls to the minimum level of 12.6% and has reached a peak of 15.3%.

Dissipative effects on a chemically and thermally radiative heat fluid flow past a shrinking porous sheet

2020 ◽  
pp. 1-14
Author(s):  
A. Shahid ◽  
M. Ali Abbas ◽  
H.L. Huang ◽  
S.R. Mishra ◽  
M.M. Bhatti
Keyword(s):  
Fluid Flow ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Chemical Reaction ◽  
Linearization Method ◽  
Surface Drag ◽  
Suction Parameter ◽  
Similarity Transformations ◽  
Dissipative Effects ◽  
Successive Linearization Method

The present study analyses the dissipative influence into an unsteady electrically conducting fluid flow embedded in a pervious medium over a shrinkable sheet. The behavior of thermal radiation and chemical reactions are also contemplated. The governing partial differential equations are reformed to ordinary differential equations by operating similarity transformations. The numerical outcomes for the arising non-linear boundary value problem are determined by implementing the Successive linearization method (SLM) via Matlab software. The velocity, temperature, and concentration magnitudes for distant values of the governing parametric quantities are conferred, and their conduct is debated via graphical curves. The surface drag coefficient increases, whereas the local Nusselt number and Sherwood number decreases for enhancing unsteadiness parameter across suction parameter. Moreover, the magnetic and suction parameters accelerate velocity magnitudes while by raising porosity parameter, velocity decelerates. Larger numeric of thermal radiation parameter and Eckert number accelerates the temperature profile while by enhancing Prandtl number it decelerates. Schmidt number and chemical reaction parameters slowdowns the concentration distribution, and the chemical reaction parameter influences on the point of chemical reaction that benefits the interface mass transfer. It is expected that the current achieved results will furnish fruitful knowledge in industrious utilities.

scholarly journals Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

2011 ◽  
Vol 4 (10) ◽  
pp. 2273-2292 ◽  
Author(s):  
S. Schweitzer ◽  
G. Kirchengast ◽  
V. Proschek
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Thermal Radiation ◽  
Rayleigh Scattering ◽  
Infrared Laser ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Wind Speed Profile ◽  
Upper Troposphere ◽  
Trace Species

Abstract. LEO-LEO infrared-laser occultation (LIO) is a new occultation technique between Low Earth Orbit (LEO) satellites, which applies signals in the short wave infrared spectral range (SWIR) within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO) method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms) of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We conclude that the set of SWIR channels proposed for implementing the LMIO method (Kirchengast and Schweitzer, 2011) provides adequate sensitivity to accurately retrieve eight trace species of key importance to climate and atmospheric chemistry (H2O, CO2, 13CO2, C18OO, CH4, N2O, O3, CO) in the upper troposphere/lower stratosphere region outside clouds under all atmospheric conditions. Two further species (HDO, H218O) can be retrieved in the upper troposphere.

scholarly journals Implicit Finite Difference Simulation of Prandtl-Eyring Nanofluid over a Flat Plate with Variable Thermal Conductivity: A Tiwari and Das Model

Mathematics ◽  
2021 ◽  
Vol 9 (24) ◽  
pp. 3153
Author(s):  
Nidal H. Abu-Hamdeh ◽  
Abdulmalik A. Aljinaidi ◽  
Mohamed A. Eltaher ◽  
Khalid H. Almitani ◽  
Khaled A. Alnefaie ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Difference ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Variable Thermal Conductivity ◽  
Solid Particles ◽  
Engine Oil ◽  
Working Fluid ◽  
Implicit Finite Difference

The current article presents the entropy formation and heat transfer of the steady Prandtl-Eyring nanofluids (P-ENF). Heat transfer and flow of P-ENF are analyzed when nanofluid is passed to the hot and slippery surface. The study also investigates the effects of radiative heat flux, variable thermal conductivity, the material’s porosity, and the morphologies of nano-solid particles. Flow equations are defined utilizing partial differential equations (PDEs). Necessary transformations are employed to convert the formulae into ordinary differential equations. The implicit finite difference method (I-FDM) is used to find approximate solutions to ordinary differential equations. Two types of nano-solid particles, aluminium oxide (Al2O3) and copper (Cu), are examined using engine oil (EO) as working fluid. Graphical plots are used to depict the crucial outcomes regarding drag force, entropy measurement, temperature, Nusselt number, and flow. According to the study, there is a solid and aggressive increase in the heat transfer rate of P-ENF Cu-EO than Al2O3-EO. An increment in the size of nanoparticles resulted in enhancing the entropy of the model. The Prandtl-Eyring parameter and modified radiative flow show the same impact on the radiative field.

Thermal analysis of a three-layered radiant porous heat exchanger including fluid flow simulation

2013 ◽  
Vol 228 (8) ◽  
pp. 1375-1390 ◽  
Author(s):  
M Sajedi ◽  
SA Gandjalikhan Nassab ◽  
E Jahanshahi Javaran
Keyword(s):  
Thermal Analysis ◽  
Porous Medium ◽  
Heat Exchanger ◽  
Thermal Radiation ◽  
Optical Thickness ◽  
Gas Flow ◽  
Flow Simulation ◽  
Local Thermal Equilibrium ◽  
Outlet Section ◽  
Energy Equations

Based on an effective energy conversion method between flowing gas enthalpy and thermal radiation, a three-layered type of porous heat exchanger (PHE) has been proposed. The PHE has one high temperature (HT) and two heat recovery (HR1 and HR2) sections. In HT section, the enthalpy of gas flow converts to thermal radiation and the opposite process happens in HR1 and HR2. In each section, a 2-D rectangular porous medium which is assumed to be absorbing, emitting and scattering is presented. For theoretical analysis of the PHE, the gas and solid phases are considered in non-local thermal equilibrium and separate energy equations are used for these two phases. Besides, in the gas flow simulation, the Fluent code is used to obtain the velocity distribution in the PHE from inlet to outlet section. For thermal analysis of the PHE, the coupled energy equations for gas and porous layer at each section are numerically solved using the finite difference method. In the computation of radiative heat flux distribution, the radiative transfer equation (RTE) is solved by the discrete ordinates method (DOM). The effects of scattering albedo, optical thickness, particle size of porous medium and inlet gas temperature on the efficiency of PHE are explored. Numerical results show that this type of PHE has high efficiency especially when the porous layers have high optical thickness. The present results are compared with those reported theoretically by other investigators and reasonable agreement is found.

Physical a priori solar radiation pressure models for GNSS satellites with the focus on BDS

2021 ◽  
Author(s):  
Bingbing Duan ◽  
Urs Hugentobler ◽  
Inga Selmke ◽  
Stefan Marz
Keyword(s):  
Optical Properties ◽  
Solar Radiation ◽  
Thermal Radiation ◽  
Radiation Pressure ◽  
Total Mass ◽  
A Priori ◽  
Solar Radiation Pressure ◽  
The Other ◽  
Time Range ◽  
Satellite Attitude

<p>A physical a priori box-wing solar radiation pressure (SRP) model is widely used by most analysis centers for Galileo and QZSS (Quasi-Zenith Satellite System) satellites, complemented by an ECOM or ECOM2 (Empirical CODE Orbit Model) model. For the other constellations, for instance GPS and GLONASS satellites, optical properties of satellite surfaces are not publicly available, especially for GPS Block IIF and GLONASS satellites. By fixing satellite surface areas and total mass to the values from some unpublished documents, we estimate satellite surface optical properties based on true GNSS measurements covering long time periods (typically this should be longer than a full beta angle time range to reduce correlations between parameters). Meanwhile, various physical effects are considered, such as yaw bias, radiator emission and thermal radiation of solar panels. We find that yaw bias of GPS Block IIA and IIR satellites does not dominate the Y-bias, it is likely that heat generated in the satellite is radiated from louvers or heat pipes on the Y side of the satellite. It is also noted that the ECOM Y0 estimates of both GPS and GLONASS satellites show clear anomaly during eclipse seasons. This indicates that the radiator emission is present when the satellite crosses shadows. Since satellite attitude during eclipse seasons could be different from the nominal yaw, potential radiator effect in the –X surface could be wrongly absorbed by the ECOM Y0 as well. By considering all the estimated parameters in an a priori model we observe clear improvement in satellite orbits, especially for GLONASS satellites. China’s Beidou-3 satellites are now providing PNT (positioning, navigation and timing) service globally. Satellite attitude, dimensions and total mass are publicly available. Also, the absorption optical properties of each satellite surface are given. With all this information, we estimate the other optical properties of Beidou satellites considering similar yaw bias, radiator and thermal radiation effects as those in GPS and GLONASS satellites.</p>

The Effect of Viscous Dissipation and Thermal Radiation in Siskoferronanofluid Flow over a Porous Medium

2021 ◽  
Vol 54 ◽  
pp. 118-131
Author(s):  
K. Saritha ◽  
R. Muthusami ◽  
M. Rameshkumar
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Thermal Radiation ◽  
Viscous Dissipation ◽  
Current Data ◽  
Convection Flow ◽  
Physical Parameters ◽  
Nickel Zinc ◽  
Comparison Table ◽  
Energy Equations

This Paper contributes heat transfer phenomena in mixed convection flow of Siskoferronanofluidover a porous surface in the presence of a temperature gradient heat sink with prescribed heatflux. The effect of viscous dissipation and thermal radiation on the flow field is also taken in to consideration. The three types of ferromagnetic particles Nickel Zinc ferrite (Ni–ZnFe2O4), ManganeseZinc ferrite (Mn1/2Zn1/2Fe2O4) and Cobalt ferrite (CoFe2O4) are considered with water (H2O)and Ethylene Glycol (C2H6O2) as conventional base fluids. The RungeKuttaFehlberg method of numerical methodology is used to solve momentum and energy equations. With the help of graphs andtables, the effect of various associated physical parameters on the velocity, temperature, Skin frictioncoefficient and Nusselt number is studied. The present results indicate that the heat transfer rate ofEthylene Glycol based Siskoferronanofluid is higher than that of water based fluid and also waterbased Siskoferronanofluid reduces shear stress of the fluid flow rapidly than Ethylene glycol basedfluid. The accuracy of the results comparison table is validated with the current data.

Heat and Mass Transfer of Temperature-Dependent Viscosity Models in a Pipe: Effects of Thermal Radiation and Heat Generation

2020 ◽  
Vol 75 (3) ◽  
pp. 225-239 ◽  
Author(s):  
Fayyaz Ahmad ◽  
Mubbashar Nazeer ◽  
Mubashara Saeed ◽  
Adila Saleem ◽  
Waqas Ali
Keyword(s):  
Thermal Radiation ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Physical Property ◽  
Solid Particles ◽  
Temperature Fields ◽  
Fluid Temperature ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity ◽  
Increasing Trends

AbstractIn this paper, a study of the flow of Eyring-Powell (EP) fluid in an infinite circular long pipe under the consideration of heat generation and thermal radiation is considered. It is assumed that the viscosity of the fluid is an exponential function of the temperature of the fluid. The flow of fluid depends on many variables, such as the physical property of each phase and shape of solid particles. To convert the given governing equations into dimensionless form, the dimensionless quantities have been used and the resultant boundary value problem is solved for the calculation of velocity and temperature fields. The analytical solutions of velocity and temperature are calculated with the help of the perturbation method. The effects of the fluidic parameters on velocity and temperature are discussed in detail. Finite difference method is employed to find the numerical solutions and compared with the analytical solution. The magnitude error in velocity and temperature is obtained in each case of the viscosity model and plotted against the radius of the pipe. Graphs are plotted to describe the influence of various parameter EP parameters, heat generation parameter and thermal radiation parameters against velocity and temperature profiles. The fluid temperature has decreasing and increasing trends with respect to radiation and heat generations parameters, respectively.

Theoretical Investigation in Thermoelastohydrodynamic Lubrication With Non-Newtonian Lubricants Under Heavy Load Change

2004 ◽  
Author(s):  
Mongkol Mongkolwongrojn ◽  
Kasame Thammakosol
Keyword(s):  
Initial Conditions ◽  
Solid Lubricants ◽  
Solid Particles ◽  
Time Dependent ◽  
Line Contact ◽  
Heavy Load ◽  
Steady State Condition ◽  
Load Change ◽  
Load Function ◽  
Energy Equations

The time-dependent thermal compressible elastohydrodynamic (EHD) lubrication of sliding line contact has been developed to investigate the effect of a sudden load change. The time-dependent modified Reynolds equation with non-Newtonian fluids has been formulated using power law’s model. In this study, the non-Newtonian dilatant fluids for liquids-solid lubricants have been purposed experimentally using the common solid particles namely, Molybdenum disulfide (MoS2) and Polytetrafluoroethylene (PTFE). The simultaneous systems of modified Reynolds and elasticity and energy equations with initial conditions were solved numerically using multigrid multilevel technique. The performance characteristics of the thermoelastohydrodynamic under line contact were presented with varying time for the pressure distribution, temperature distribution and oil film thickness. The transient response of the line contact between two surfaces was simulated under a heavy step load function. The coefficients of friction were also presented in this work at steady state condition with varying particle concentration. This simulation showed a significant effect of liquid-solid on thermoelastohydrodynamic (TEHD) lubrication under heavy load conditions.

Material Properties of Refractory Concrete under High Temperature

2015 ◽  
Vol 1126 ◽  
pp. 155-160
Author(s):  
Stanislav Šťastník ◽  
František Šot ◽  
Jiří Vala
Keyword(s):  
High Temperature ◽  
Solar Radiation ◽  
Physical Properties ◽  
Material Properties ◽  
Refractory Concrete ◽  
Thermal Storage ◽  
Thermal Transfer ◽  
The Core

The paper presents the validation of physical properties of refractory concrete with heavy filling, using the measurements under high temperature, assumed for the construction of a thermal storage. The whole system, consisting of the storage core and of the insulation container, is characterized by non-stationary thermal transfer, supplied from solar radiation into the core. The validation of behaviour of the system (including its sleeping state and the dynamics of charging and discharging) is needed for the optimization of its size parameters.

scholarly journals Nanoscale Thermal Transfer – An Invitation to Fluctuation Electrodynamics

2017 ◽  
Vol 72 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Carsten Henkel
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Near Field ◽  
Electromagnetic Theory ◽  
Physical Content ◽  
Thermal Transfer ◽  
The Status ◽  
Basic Concepts

AbstractAn electromagnetic theory of thermal radiation is outlined, based on the fluctuation electrodynamics of Rytov and co-workers. We discuss the basic concepts and the status of different approximations. The physical content is illustrated with a few examples on near-field heat transfer.

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