scholarly journals Entropy generation in thermally radiated hybrid nanofluid through an electroosmotic pump with ohmic heating: Case of synthetic cilia regulated stream

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110259
Author(s):  
Sufian Munawar ◽  
Najma Saleem
Keyword(s):  
Numerical Solutions ◽  
Flow System ◽  
Ohmic Heating ◽  
Pressure Rise ◽  
Hybrid Nanofluid ◽  
Electroosmotic Pump ◽  
Efficient Delivery ◽  
Channel Surface ◽  
Nanofluidic Devices ◽  
Regulated Stream

Synthetic cilia-regulated transports through micro and nanofluidic devices guarantee an efficient delivery of drugs and other biological substances. Entropy analysis of cilia stimulated transport of thermally radiated hybrid nanofluid through an electroosmotic pump is conducted in this study. Joint effects of applied Lorentz force and Ohmic heating on the intended stream are also studied. Metachronal arrangements of cilia field coating channel inner side, are liable to generate current in the fluid. After using the lubrication and the Debye-Huckel estimations, numerical solutions of the envisioned problem are obtained. For pressure rise per metachronal wavelength, the pressure gradient is numerically integrated. The analysis reveals that high electric potential results in reducing the heat transfer effects in the flow system. The enhancement of flow is noticed near the channel surface for higher electroosmotic parameters. The irreversibility in the channel decreases when the Helmholtz-Smoluchowski velocity is applied in the opposite direction of the flow and thus produces the fluid friction irreversibility.

scholarly journals Significance of Synthetic Cilia and Arrhenius Energy on Double Diffusive Stream of Radiated Hybrid Nanofluid in Microfluidic Pump under Ohmic Heating: An Entropic Analysis

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1292
Author(s):  
Najma Saleem ◽  
Sufian Munawar
Keyword(s):  
Numerical Solutions ◽  
Ohmic Heating ◽  
Entropy Generation Rate ◽  
Hybrid Nanofluid ◽  
Minimum Entropy ◽  
Mass Dispersion ◽  
Electroosmotic Pumps ◽  
Arrhenius Energy ◽  
Minimum Entropy Generation ◽  
Double Diffusive

This study investigates the thermal aspects of magnetohydrodynamic double diffusive flow of a radiated Cu-CuO/Casson hybrid nano-liquid through a microfluidic pump in the presence of electroosmosis effects. Shared effects of the Arrhenius activation energy and the Joule heating on the intended liquid transport are also incorporated. The inner wall of the pump is covered with electrically charged fabricated cilia mat that facilitates flow actuation and micro-mixing process. The governing equations for the proposed problem are simplified by utilizing the Debye-Hückel and lubrication approximations. The numerical solutions are calculated with the aid of shooting technique. The analysis reports that the substantial effects of electroosmosis contribute an important role in cooling process. Existence of electric double layer stimulates an escalation in liquid stream in the vicinity of the pump surface. The Arrhenius energy input strengthens the mass dispersion and regulates the thermal treatment. The proposed geometry delivers a deep perception that fabricated cilia in electroosmotic pumps are potential pharmaceutical micromixers for an effective flow and minimum entropy generation rate.

scholarly journals Significance of Slippage and Electric Field in Mucociliary Transport of Biomagnetic Fluid

Lubricants ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 48
Author(s):  
Sufian Munawar
Keyword(s):  
Shear Stress ◽  
Flow Direction ◽  
Pressure Rise ◽  
Physical Parameters ◽  
Slippage Effect ◽  
Channel Surface ◽  
Electro Osmosis ◽  
Biomagnetic Fluid ◽  
Velocity Pressure ◽  
Metachronal Waves

Shear stress at the cilia wall is considered as an imperative factor that affects the efficiency of cilia beatings as it describes the momentum transfer between the fluid and the cilia. We consider a visco-inelastic Prandtl fluid in a ciliated channel under electro-osmotic pumping and the slippage effect at cilia surface. Cilia beating is responsible for the stimulation of the flow in the channel. Evenly distributed cilia tend to move in a coordinated rhythm to mobilize propulsive metachronal waves along the channel surface by achieving elliptic trajectory movements in the flow direction. After using lubrication approximations, the governing equations are solved by the perturbation method. The pressure rise per metachronal wavelength is obtained by numerically integrating the expression. The effects of the physical parameters of interest on various flow quantities, such as velocity, pressure gradient, pressure rise, stream function, and shear stress at the ciliated wall, are discussed through graphs. The analysis reveals that the axial velocity is enhanced by escalating the Helmholtz–Smoluchowski velocity and the electro-osmosis effects near the elastic wall. The shear stress at the ciliated boundary elevates with an increase in the cilia length and the eccentricity of the cilia structure.

scholarly journals Hybrid nanofluid flow through a spinning Darcy–Forchheimer porous space with thermal radiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anwar Saeed ◽  
Muhammad Jawad ◽  
Wajdi Alghamdi ◽  
Saleem Nasir ◽  
Taza Gul ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Flow System ◽  
Thermal Characteristics ◽  
Graphical Form ◽  
Hybrid Nanofluid ◽  
Porous Space ◽  
Variable Porosity ◽  
Homotopy Analysis ◽  
Porosity And Permeability ◽  
Flow Through

AbstractThis work investigates numerically the solution of Darcy–Forchheimer flow for hybrid nanofluid by employing the slip conditions. Basically, the fluid flow is produced by a swirling disk and is exposed to thermal stratification along with non-linear thermal radiation for controlling the heat transfer of the flow system. In this investigation, the nanoparticles of titanium dioxide and aluminum oxide have been suspended in water as base fluid. Moreover, the Darcy–Forchheimer expression is used to characterize the porous spaces with variable porosity and permeability. The resulting expressions of motion, energy and mass transfer in dimensionless form have been solved by HAM (Homotopy analysis method). In addition, the influence of different emerging factors upon flow system has been disputed both theoretically in graphical form and numerically in the tabular form. During this effort, it has been recognized that velocities profiles augment with growing values of mixed convection parameter while thermal characteristics enhance with augmenting values of radiation parameters. According to the findings, heat is transmitted more quickly in hybrid nanofluid than in traditional nanofluid. Furthermore, it is estimated that the velocities of fluid $$f^{\prime}\left( \xi \right),g\left( \xi \right)$$ f ′ ξ , g ξ are decayed for high values of $$\phi_{1} ,\phi_{2} ,\,Fr$$ ϕ 1 , ϕ 2 , F r and $$k_{1}$$ k 1 factors.

Influences of Marangoni Convection and Variable Magnetic Field Hybrid Nanofluid Thin Film Flow past a Stretching Surface

2021 ◽  
Author(s):  
Noor Wali Khan ◽  
Arshad Khan ◽  
Muhammad Usman ◽  
Taza Gul ◽  
Abir Mouldi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Film Flow ◽  
Marangoni Convection ◽  
Flow System ◽  
Thermal Characteristics ◽  
Variable Magnetic Field ◽  
Current Work ◽  
Hybrid Nanofluid ◽  
Thin Film Flow

Abstract The investigations about thin-film flow play a vital role in the field of optoelectronics and magnetic devices. Thin films are reasonably hard and thermally stable but are more fragile. The thermal stability of thin film can be further improved by incorporating the effects of nanoparticles. In the current work, a stretchable surface is considered upon which hybrid nanofluid thin-film flow is taken into account. The idea of augmenting heat transmission is focused in current work by making use of hybrid nanofluid. The flow is affected by variations in the viscous forces along with viscous dissipation effects and Marangoni convection. A time-constrained magnetic field is applied in the normal direction to the flow system. The equations governing the flow system are shifted to a non-dimensional form by applying similarity variables. The homotopy analysis method (HAM) has been employed to find the solution of resultant equations. It has been noticed in this study that, the flow characteristics decline with augmentation in magnetic, viscosity, and unsteadiness parameters while grow up with enhancing values of thin-film parameter. Thermal characteristics are supported by the growing values of the Eckert number and unsteadiness parameter while opposed by the viscosity parameter and Prandtl number. The numerical impact of different emerging parameters upon skin friction and Nusselt number has been calculated in tabular form. A comparison of current work with established result has carried out with a good agreement in both results.

Numerical study of toroidal magnetic field on the self-gravitating protoplanetary disks

2020 ◽  
Vol 29 (09) ◽  
pp. 2050067
Author(s):  
Hanifeh Ghanbarnejad ◽  
Maryam Ghasemnezhad
Keyword(s):  
Magnetic Field ◽  
Accretion Disks ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Ohmic Heating ◽  
The Self ◽  
Toroidal Magnetic Field ◽  
Heating Process ◽  
Heating And Cooling ◽  
The Magnetic Field

In this paper, we study the self-gravitating accretion disks by considering the toroidal component of magnetic field, [Formula: see text] and wind/outflow in the flow and also investigate the effect of two parameters, [Formula: see text] and [Formula: see text] corresponding to magnetic field on the latitudinal structure of such accretion disks. The cooling of the disk is parameterized simply as, [Formula: see text] (where [Formula: see text] is the internal energy and [Formula: see text] is the cooling timescale and [Formula: see text] is a free constant) and the heating rate is decomposed into two components, magnetic field and viscosity dissipations. We have shown that when the toroidal magnetic field becomes stronger, the heating process (viscous and resistivity) and the radiative cooling rate increase. Ohmic heating is much bigger than viscous heating and cooling, so we must consider the role of the magnetic field in the energy equation. Our numerical solutions show that the thickness of the disk decreases with strong toroidal component of magnetic field. The magnetic field leads to production of the outflow in the low latitude. So, by increasing the toroidal component of the magnetic field, the regions which belong to inflow decrease and the disk is cooled.

scholarly journals Peristaltic motion of a Johnson-Segalman fluid in a planar channel

2003 ◽  
Vol 2003 (1) ◽  
pp. 1-23 ◽  
Author(s):  
T. Hayat ◽  
Y. Wang ◽  
A. M. Siddiqui ◽  
K. Hutter
Keyword(s):  
Characteristic Time ◽  
Numerical Solutions ◽  
Pressure Rise ◽  
Travelling Wave ◽  
Weissenberg Number ◽  
Planar Channel ◽  
Two Dimensional ◽  
Peristaltic Motion ◽  
Two Dimensional Flow ◽  
Large Wavelength

This paper is devoted to the study of the two-dimensional flow of a Johnson-Segalman fluid in a planar channel having walls that are transversely displaced by an infinite, harmonic travelling wave of large wavelength. Both analytical and numerical solutions are presented. The analysis for the analytical solution is carried out for small Weissenberg numbers. (A Weissenberg number is the ratio of the relaxation time of the fluid to a characteristic time associated with the flow.) Analytical solutions have been obtained for the stream function from which the relations of the velocity and the longitudinal pressure gradient have been derived. The expression of the pressure rise over a wavelength has also been determined. Numerical computations are performed and compared to the perturbation analysis. Several limiting situations with their implications can be examined from the presented analysis.

3D numerical simulation of the supersonic combustion of H2

2006 ◽  
Vol 110 (1114) ◽  
pp. 773-782 ◽  
Author(s):  
Prashant Dinde ◽  
A. Rajasekaran ◽  
V. Babu
Keyword(s):  
Static Pressure ◽  
Fuel Injection ◽  
Numerical Solutions ◽  
Pressure Rise ◽  
Reacting Flows ◽  
Single Step ◽  
Supersonic Combustion ◽  
Finite Rate ◽  
Average Value ◽  
The Mean

Results from numerical simulations of supersonic combustion of H2 are presented. The combustor has a single stage fuel injection parallel to the main flow from the base of a wedge. The simulations have been performed using FLUENT. Realisable k-ε model has been used for modelling turbulence and single step finite rate chemistry has been used for modelling the H2-Air kinetics. All the numerical solutions have been obtained on grids with average value for wall y+ less than 40. Numerically predicted profiles of static pressure, axial velocity, turbulent kinetic energy and static temperature for both non-reacting as well as reacting flows are compared with the experimental data. The RANS calculations are able to predict the mean and fluctuating quantities reasonably well in most regions of the flow field. However, the single step kinetics predicts heat release much more rapid than what was seen in the experiments. Nonetheless, the overall pressure rise in the combustor due to combustion is predicted well. Also, the k-ε model is not able to predict the fluctuating quantities in the base region of the wedge where there is strong anisotropy in the presence of combustion.

Numerical solution of unsteady boundary-layer separation in supersonic flow: upstream moving wall

2012 ◽  
Vol 706 ◽  
pp. 413-430 ◽  
Author(s):  
R. Yapalparvi ◽  
L. L. Van Dommelen
Keyword(s):  
Boundary Layer ◽  
Supersonic Flow ◽  
Numerical Solutions ◽  
Stokes Equations ◽  
Pressure Rise ◽  
Boundary Layer Separation ◽  
Recirculation Region ◽  
Characteristic Time Scale ◽  
Layer Separation ◽  
Moving Wall

AbstractThis paper is an extension of work on separation from a downstream moving wall by Ruban et al. (J. Fluid. Mech., vol. 678, 2011, pp. 124–155) and is in particular concerned with the boundary-layer separation in unsteady two-dimensional laminar supersonic flow. In a frame attached to the wall, the separation is assumed to be provoked by a shock wave impinging upon the boundary layer at a point that moves downstream with a non-dimensional speed which is assumed to be of order ${\mathit{Re}}^{\ensuremath{-} 1/ 8} $ where $\mathit{Re}$ is the Reynolds number. In the coordinate system of the shock however, the wall moves upstream. The strength of the shock and its speed are allowed to vary with time on a characteristic time scale that is large compared to ${\mathit{Re}}^{\ensuremath{-} 1/ 4} $. The ‘triple-deck’ model is used to describe the interaction process. The governing equations of the interaction problem can be derived from the Navier–Stokes equations in the limit $\mathit{Re}\ensuremath{\rightarrow} \infty $. The numerical solutions are obtained using a combination of finite differences along the streamwise direction and Chebyshev collocation along the normal direction in conjunction with Newton linearization. In the present study with the wall moving upstream, the evidence is inconclusive regarding the so-called ‘Moore–Rott–Sears’ criterion being satisfied. Instead it is observed that the pressure rise from its initial value is very slow and that a recirculation region forms, the upstream part of which is wedge-shaped, as also observed in turbulent marginal separation for large values of angle of attack.

scholarly journals Transportation of Al2O3-SiO2-TiO2 modified nanofluid over an exponentially stretching surface with inclined magnetohydrodynamic

2021 ◽  
Vol 25 (Spec. issue 2) ◽  
pp. 279-285
Author(s):  
Prvaeen Dadheech ◽  
Priyanka Agrawal ◽  
Anil Sharma ◽  
Kottakkaran Nisar ◽  
Sunil Purohit
Keyword(s):  
Magnetic Field ◽  
Base Fluid ◽  
Numerical Solutions ◽  
Graphical Representation ◽  
Hybrid Nanofluid ◽  
Stretching Surface ◽  
Similarity Transformations ◽  
Exponentially Stretching ◽  
Inclined Angle ◽  
Fourth Order Method

In the present study Al2O3-SiO2-TiO2/C2H6O2 modified nanofluid flow over a stretching surface is considered with imposed inclined magnetic field. Three different suspended nanoparticles in a base fluid are considered in this next generation of hybrid nanofluid called as modified nanofluid. Ethanol glycol is taken as a base fluid with suspension of three nanoparticles of Al2O3, SiO2, and TiO2. The mathematical model of the flow is encountered by Runga-Kutta fourth order method using appropriate similarity transformations. As a key result it is observed that the capacity of heat transportation of modified nanofluid is higher as compared with nanofluids and hybrid nanofluids. Numerical solutions with graphical representation are presented. With increased inclined angle, parameter of magnetic field, and volume friction parameter a decrement in velocity field has been noticed for modified nanofluid.

Transient Analysis of Mixed Free-Surface-Pressurized Flows With Modified Slot Model: Part 2 — Similarity Law and Eigenvalue Problem

2003 ◽  
Author(s):  
Kazutoshi Arai ◽  
Katsuhiro Yamamoto ◽  
Mitsuhiro Saitou ◽  
Shigeru Fukumoto
Keyword(s):  
Free Surface ◽  
Differential Equations ◽  
Numerical Solutions ◽  
Transient Flow ◽  
Pressure Rise ◽  
Complex Eigenvalue ◽  
Velocity Difference ◽  
Model Calculations ◽  
Pressurized Flows ◽  
Entrapped Air

To analyze transient free-surface-pressurized flows with entrapped air in a drainage system, a virtual slot model with ceiling has been introduced. Using this model, calculations for the reduced model and the actual size model are carried out to examine a scale effect on the transient flow. The results show that up-scaling the system causes the increase in compressibility of entrapped air so that the rate of pressure rise decreases. Next, it is confirmed that the partial differential equations for the modified slot model have real eigenvalues and then the initial value problem is well-posed when the velocity difference between air and water is not so large. The increase in the velocity difference yields a system having complex eigenvalue, however the well behaved numerical solutions can be obtained since the friction terms in the differential equations suppress the numerical instability.

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