scholarly journals Heat Induction by Viscous Dissipation Subjected to Symmetric and Asymmetric Boundary Conditions on a Small Oscillating Flow in a Microchannel

Symmetry ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 499 ◽  
Author(s):  
Chih Tso ◽  
Chee Hor ◽  
Gooi Chen ◽  
Chee Kok

The heat induced by viscous dissipation in a microchannel fluid, due to a small oscillating motion of the lower plate, is investigated for the first time. The methodology is by applying the momentum and energy equations and solving them for three cases of standard thermal boundary conditions. The first two cases involve symmetric boundary conditions of constant surface temperature on both plates and both plates insulated, respectively. The third case has the asymmetric conditions that the lower plate is insulated while the upper plate is maintained at constant temperature. Results reveal that, although the fluid velocity is only depending on the oscillation rate of the plate, the temperature field for all three cases show that the induced heating is dependent on the oscillation rate of the plate, but strongly dependent on the parameters Brinkman number and Prandtl number. All three cases prove that the increasing oscillation rate or Brinkman number and decreasing Prandtl number, when it is less than unity, will significantly increase the temperature field. The present model is applied to the synovial fluid motion in artificial hip implant and results in heat induced by viscous dissipation for the second case shows remarkably close agreement with the experimental literature.

2019 ◽  
Vol 1 (1) ◽  
pp. 13-17
Author(s):  
Chee Hao Hor ◽  
Chih Ping Tso ◽  
Gooi Mee Chen

The viscous dissipation effects in a microchannels caused by an oscillatory lower surface is investigated numerically. An asymmetric thermal boundary condition, particularly at upper plate insulated and lower plate with constant surface temperature is solved and analyzed in details graphically. Results reveal that effect of temperature field is strongly dependent on Brinkman number, while the thermal diffusion rate on the heat induced relies on the Prandtl number. The angular frequency has influence on the temperature field gradient.


2019 ◽  
Vol 20 (5) ◽  
pp. 502 ◽  
Author(s):  
Aaqib Majeed ◽  
Ahmed Zeeshan ◽  
Farzan Majeed Noori ◽  
Usman Masud

This article is focused on Maxwell ferromagnetic fluid and heat transport characteristics under the impact of magnetic field generated due to dipole field. The viscous dissipation and heat generation/absorption are also taken into account. Flow here is instigated by linearly stretchable surface, which is assumed to be permeable. Also description of magneto-thermo-mechanical (ferrohydrodynamic) interaction elaborates the fluid motion as compared to hydrodynamic case. Problem is modeled using continuity, momentum and heat transport equation. To implement the numerical procedure, firstly we transform the partial differential equations (PDEs) into ordinary differential equations (ODEs) by applying similarity approach, secondly resulting boundary value problem (BVP) is transformed into an initial value problem (IVP). Then resulting set of non-linear differentials equations is solved computationally with the aid of Runge–Kutta scheme with shooting algorithm using MATLAB. The flow situation is carried out by considering the influence of pertinent parameters namely ferro-hydrodynamic interaction parameter, Maxwell parameter, suction/injection and viscous dissipation on flow velocity field, temperature field, friction factor and heat transfer rate are deliberated via graphs. The present numerical values are associated with those available previously in the open literature for Newtonian fluid case (γ 1 = 0) to check the validity of the solution. It is inferred that interaction of magneto-thermo-mechanical is to slow down the fluid motion. We also witnessed that by considering the Maxwell and ferrohydrodynamic parameter there is decrement in velocity field whereas opposite behavior is noted for temperature field.


2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Hazem Ali Attia ◽  
Mohamed Eissa Sayed-Ahmed

The unsteady magnetohydrodynamics flow of an electrically conducting viscous incompressible non-Newtonian Casson fluid bounded by two parallel nonconducting porous plates is studied with heat transfer considering the Hall effect. An external uniform magnetic field is applied perpendicular to the plates and the fluid motion is subjected to a uniform suction and injection. The lower plate is stationary and the upper plate is suddenly set into motion and simultaneously suddenly isothermally heated to a temperature other than the lower plate temperature. Numerical solutions are obtained for the governing momentum and energy equations taking the Joule and viscous dissipations into consideration. The effect of the Hall term, the parameter describing the non-Newtonian behavior, and the velocity of suction and injection on both the velocity and temperature distributions are studied.


1989 ◽  
Vol 2 (1) ◽  
pp. 13-31 ◽  
Author(s):  
Lokenath Debnath ◽  
A. K. Ghosh

A study is made of the unsteady motion of an incompressible viscous conducting fluid with embedded small spherical particles bounded by two infinite rigid non-conducting plates. The operational method derives exact solutions for the fluid and the particle velocities and the wall shear stress. The quantitative evaluation of these results is considered when the two plates oscillate in phase but with different frequencies. The results are shown graphically for different values of the time period of oscillations of the plates which represent the cases: (i) the lower plate oscillates with time period less than the upper, (ii) both the plates oscillate with the same time period, (iii) the lower plate oscillates with time period greater than the upper. The magnetic field damps the fluid motion for all values of the time period of oscillations of the plates. When the time periods are small, i.e., when the plates oscillate with high frequency, the fluid motion is retarded by the particles. However, when the plates oscillate with larger time periods (smaller frequencies), the fluid velocity is increased by the presence of the particles at the early stage of the motion, and this effect persists until the equilibrium is reached when the particles exert their influence to resist the flow. The drag on the plate, which is evaluated numerically for the lower plate oscillating with large time period, depends on the ratio of the time periods of the oscillating plates. If the ratio of the time periods is not equal to unity, the drag on the plate, irrespective of the values of the magnetic field, oscillates with larger amplitude compared to its value when the ratio of the time periods is equal to unity. Further, for the ratio of the time periods less than or equal to unity and for any fixed values of the magnetic field, the drag increases by the presence of the particles after a time t≈1.2 which is the upper time limit for the non-equilibrium stress-value to exist. In a similar situation, a reverse effect, i.e., the decrease of the drag with increasing particle concentration, is found for the ratio of the time periods being greater than unity.


Author(s):  
Syazwani Mohd Zokri ◽  
Nur Syamilah Arifin ◽  
Muhammad Khairul Anuar Mohamed ◽  
Mohd Zuki Salleh ◽  
Abdul Rahman Mohd Kasim ◽  
...  

The present paper focuses on the influence of radiation and viscous dissipation on magnetohydrodynamic (MHD) flow and heat transfer of a Jeffrey fluid over a stretching sheet with convective boundary conditions (CBC). The governing equations are reduced to non-linear ordinary differential equations by using similarity transformation variables and then solved by using Runge-Kutta-Fehlberg method. The results generated from the numerical computations are presented in the form of tables and graphs for some values of Deborah number, ratio of relaxation to retardation times, Eckert number, radiation parameter and magnetic parameter. It is found that the distribution of fluid velocity is noticeably increased with an increment in Deborah number while the distribution of temperature shows the opposite trend.


2020 ◽  
Vol 9 (4) ◽  
pp. 362-374
Author(s):  
J. C. Umavathi ◽  
Ali J. Chamkha

Nanotechnology has infiltrated into duct design in parallel with many other fields of mechanical, medical and energy engineering. Motivated by the excellent potential of nanofluids, a subset of materials engineered at the nanoscale, in the present work, a new mathematical model is developed for natural convection in a vertical duct containing nanofluid. Numerical scrutiny for the double-diffusive free and forced convection within a duct encumbered with nanofluid is performed. Buongiorno’s model is deployed to define the nanofluid. Robin boundary conditions are used to define the surface boundary conditions. Thermal and concentration equations envisage the viscous, Brownian motion, thermosphores of the nanofluid, Soret and Dufour effects. Using the Boussi-nesq approximation the solutal buoyancy effect as a result of gradients in concentration are incorporated. The conservation equations which are nonlinear are numerically estimated using fourth order Runge-Kutta methodology and analytically ratifying regular perturbation scheme. The mass, heat, nanoparticle concentration and species concentration fields on eight dimensionless physical parameters such as thermal and mass Grashof numbers, Brownian motion parameter, thermal parameter, Prandtl number, Eckert number, Schmidt parameter, and Soret parameter are calculated. The impact of these parameters are outlined pictorially. The velocity and temperature fields are boosted with the thermal Grashof number. The Soret and the Schemidt parameters reduces the nanoparticle volume fraction but it heightens the momentum, temperature and concentration. At the cold wall thermal and concentration Grashof numbers reduces the Nusselt values but they increase the Nusselt values at the hot wall. The reversal consequence was attained at the hot plate. The perturbation and Runge-Kutta solutions are equal in the nonappearance of Prandtl number. The (E. Zanchini, Int. J. Heat Mass Transfer 41, 3949 (1998)). results are restored for the regular fluid. The heat transfer rate is high for nanofluid when matched with regular fluid.


2013 ◽  
Vol 8-9 ◽  
pp. 225-234
Author(s):  
Dalia Sabina Cimpean

The present study is focused on the mixed convection fluid flow through a porous medium, when a different amount of nanoparticles is added in the base fluid. The nanofluid saturates the porous matrix and different situations of the flow between two walls are presented and discussed. Alternatively mathematical models are presented and discussed. A solution of a system which contains the momentum, Darcy and energy equations, together with the boundary conditions involved, is given. The behavior of different nanofluids, such thatAu-water, Ag-waterandFe-wateris graphically illustrated and compared with the previous results.The research target is to observe the substantial increase of the thermophysical fluid properties, when the porous medium issaturated by a nanofluid instead of a classical Newtonian fluid.


Author(s):  
Abbas Hazbavi

In this study, the influences of the applied magnetic field and fluid elasticity were investigated for a nonlinear viscoelastic fluid obeying the Carreau equation between concentric annulus where the inner cylinder rotates at a constant angular velocity and the outer cylinder is stationary. The governing motion and energy balance equations are coupled while viscous dissipation is taken into account, adding complexity to the already highly correlated set of differential equations. The numerical solution is obtained for the narrow gap limit and steady-state base flow. Magnetic field effect on local entropy generation due to steady two-dimensional laminar forced convection flow was investigated. This study was focused on the entropy generation characteristics and its dependency on various dimensionless parameters. The effects of the Hartmann number, the Brinkman number, the Deborah number, and the fluid elasticity on the stability of the flow were investigated. The application of the magnetic field induces a resistive force acting in the opposite direction of the flow, thus causing its deceleration. Moreover, the study shows that the presence of magnetic field tends to slowdown the fluid motion and thus increases the fluid temperature. However, the total entropy generation number decreases as the Hartmann number and fluid elasticity increase and it increases with increasing Brinkman number.


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