Electromagnetohydrodynamic peristaltic flow of a couple stress nanofluid through a vertical annulus in the presence of Hall currents and thermal radiation

2021 ◽  
pp. 1-17
Author(s):  
M.H. Haroun
Keyword(s):  
Gold Nanoparticles ◽  
Thermal Radiation ◽  
Couple Stress ◽  
Amplitude Ratio ◽  
Electrical Potential ◽  
Diffusion Constant ◽  
Cylindrical Tube ◽  
Moving Frame ◽  
Brownian Diffusion ◽  
Vertical Annulus

This paper investigates the electric properties of gold nanoparticles mixed with a convection dielectric couple stress fluid inside a vertical cylindrical tube with moving endoscope in the presence of Hall currents and thermal radiation. Under the long wavelength approximation and the use of appropriate conversion relationships between fixed and moving frame coordinates, the exact solutions have been evaluated for temperature distribution, gold nanoparticles concentration, electrical potential function and nanofluid pressure, while analytical solution is found for the axial velocity using the homotopy analysis method. The results show that the presence of the electric field enhances the effects of Brownian motion parameter, thermophoresis parameter, radiation parameter, Hall currents and wave amplitude ratio on the axial nanofluid velocity, while it was found that its presence reduces the effects of couple stress parameter, thermophoresis diffusion constant and Brownian diffusion constant.

scholarly journals A New Approach for Study the Electrohydrodynamic Oscillatory Flow Through a Porous Medium in a Heating Compliant Channel

2020 ◽  
Vol 25 (3) ◽  
pp. 30-44
Author(s):  
M.H. Haroun
Keyword(s):  
Potential Function ◽  
Oscillatory Flow ◽  
Amplitude Ratio ◽  
Electrical Potential ◽  
Fluid Pressure ◽  
Wave Number ◽  
Moving Frame ◽  
Secondary Wave ◽  
Regular Perturbation ◽  
New Approach

AbstractThe governing equations of an electrohydrodynamic oscillatory flow were simplified, using appropriate nondimensional quantities and the conversion relationships between fixed and moving frame coordinates. The obtained system of equations is solved analytically by using the regular perturbation method with a small wave number. In this study, modified non-dimensional quantities were used that made fluid pressure in the resulting equations dependent on both axial and vertical coordinates. The current study is more realistic and general than the previous studies in which the fluid pressure is considered functional only in the axial coordinate. A new approach enabled the author to find an analytical form of fluid pressure while previous studies have not been able to find it but have found only the pressure gradient. Analytical expressions for the stream function, electrical potential function and temperature distribution are obtained. The results show that the electrical potential function decreases by the increase of the Prandtl number, secondary wave amplitude ratio and width of the channel.

PERISTALTIC FLOW OF COUPLE-STRESS CONDUCTING FLUIDS THROUGH A POROUS CHANNEL: APPLICATIONS TO BLOOD FLOW IN THE MICRO-CIRCULATORY SYSTEM

2011 ◽  
Vol 19 (03) ◽  
pp. 461-477 ◽  
Author(s):  
DHARMENDRA TRIPATHI
Keyword(s):  
Frictional Force ◽  
Couple Stress ◽  
Amplitude Ratio ◽  
Circulatory System ◽  
Mechanical Efficiency ◽  
Peristaltic Flow ◽  
Porous Channel ◽  
Stress Parameter ◽  
Permeability Parameter ◽  
Conducting Fluids

The present investigation is devoted to study a theoretical investigation of the peristaltic flow of a couple-stress conducting fluids in a porous channel under the influence of slip boundary condition. This study is applicable to the physiological flow of blood in the micro-circulatory system, by taking account of the particle size effect. The expressions for axial velocity, pressure gradient, stream function, frictional force and mechanical efficiency are obtained under the small Reynolds number and the large wavelength approximations. Effects of different physical parameters reflecting permeability parameter, couple-stress parameter, Hartmann number as well as amplitude ratio on pumping characteristics, frictional force, mechanical efficiency and trapping of peristaltic flow pattern are studied. The computational and numerical results are presented in graphical form. On the basis of our discussion, it is concluded that pressure reduces by increasing the magnitude of couple-stress parameter, permeability parameter, slip parameter, whereas it enhances by increasing the magnitude of magnetic field and amplitude ratio.

Numerical simulation of couple stress nanofluid flow in magneto-porous medium with thermal radiation and a chemical reaction

2018 ◽  
Vol 339 ◽  
pp. 820-836 ◽  
Author(s):  
Hloniphile Sithole ◽  
Hiranmoy Mondal ◽  
Sicelo Goqo ◽  
Precious Sibanda ◽  
Sandile Motsa
Keyword(s):  
Numerical Simulation ◽  
Porous Medium ◽  
Thermal Radiation ◽  
Chemical Reaction ◽  
Couple Stress ◽  
Nanofluid Flow

Pool Boiling Heat Transfer Enhancement of Water by Gold Nanoparticles With an Electrophoretic Deposition Method

2018 ◽  
Author(s):  
Zhen Cao ◽  
Anh Duc Pham ◽  
Zan Wu ◽  
Tautgirdas Ruzgas ◽  
Cathrine Alber ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gold Nanoparticles ◽  
Electrophoretic Deposition ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Electrical Potential ◽  
Heat Fluxes ◽  
Deposition Method ◽  
Pool Boiling Heat Transfer ◽  
Modified Surfaces

Saturated pool boiling heat transfer of water is investigated experimentally on copper surfaces with nanoparticle coatings at atmospheric pressure. The coatings are generated by an electrophoretic deposition method (EPD). Three modified surfaces are prepared with gold nanoparticles of 0.20 mg, 0.25 mg and 0.30 mg, respectively. During the deposition, ethanol works as the solvent while the electrical potential and deposition time are controlled as 9.5 V and 30 min, respectively. The experimental results show that heat transfer coefficients (HTC) and critical heat fluxes (CHF) are enhanced on the modified surfaces. HTC increases with decreasing thickness of the coating, while CHF increases with increasing thickness of the coating. CHFs of EPD-0.20 mg, EPD-0.25 mg and EPD-0.30 mg are 93 W/cm2, 123 W/cm2 and 142 W/cm2, respectively, which are increased by 7%, 41% and 63% compared with the smooth surface. EPD-0.20 mg performs the best on heat transfer, with a maximum enhancement of around 60%. At the end, a brief review about mechanistic models of heat transfer at low and moderate heat fluxes is provided, based on which, the reasons why heat transfer is enhanced are discussed.

PERISTALTIC FLOW OF COUPLE-STRESS FLUID WITH HEAT AND MASS TRANSFER: AN APPLICATION IN BIOMEDICINE

2015 ◽  
Vol 15 (04) ◽  
pp. 1550042 ◽  
Author(s):  
S. HINA ◽  
M. MUSTAFA ◽  
T. HAYAT ◽  
A. ALSAEDI
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Couple Stress ◽  
Amplitude Ratio ◽  
Circulatory System ◽  
Particle Size Effect ◽  
Couple Stress Fluid ◽  
Electrically Conducting ◽  
Fluid Parameter ◽  
Compliant Walls

Analysis is performed for the simultaneous effects of heat and mass transfer on the peristaltic transport of an electrically conducting couple-stress fluid in a compliant walls channel. The study may be useful in understanding the physiological flow of blood through micro-circulatory system in the presence of particle-size effect. Long wavelength and low Reynolds number aspects are taken into consideration. Exact solutions for stream function, temperature and concentration are derived. Impact of pertinent parameters like the couple-stress fluid parameter (γ), Hartman number (M), amplitude ratio (ϵ), elastic parameters (E1, E2, E3, E4, E5), Brinkman number (Br) and Schmidt number (Sc). It is observed that velocity and temperature distributions are greater for couple stress fluid when compared with the Newtonian fluid.

Free Convection in a Vertical Annulus With Constant Heat Flux on the Inner Wall

1983 ◽  
Vol 105 (3) ◽  
pp. 454-459 ◽  
Author(s):  
M. Keyhani ◽  
F. A. Kulacki ◽  
R. N. Christensen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Rayleigh Number ◽  
Free Convection ◽  
Thermal Radiation ◽  
Outer Cylinder ◽  
Working Fluid ◽  
Spent Fuel ◽  
Transfer Coefficients ◽  
Vertical Annulus

Heat transfer measurements are presented for free convection in a vertical annulus wherein the inner cylinder is at constant surface heat flux and the outer cylinder is at constant temperature. Overall heat transfer data are corrected for thermal radiation in the annulus. Rayleigh numbers span the conduction, transition and boundary layer regimes of flow, and average heat transfer coefficients are obtained with air and helium as the working fluids. The range of Rayleigh number is 103 < Ra < 2.3 × 106; the radius ratio is 4.33; and the aspect ratio (cylinder length divided by annular gap) is 27.6. Energy transferred by thermal radiation varies with Rayleigh number and working fluid. With air, thermal radiation can account for up to 50 percent of the heat transfer. With helium, radiation can account for up to 30 percent of the heat transfer rate. The results of the study provide data relevant to the design and performance assessment of spent fuel packages as part of the National Waste Terminal Storage Program for nuclear waste isolation.

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