scholarly journals Non-Similar Solution of G-jitter Induced Unsteady Magnetohydrodynamic Radiative Slip Flow of Nanofluid

2020 ◽  
Vol 10 (4) ◽  
pp. 1420 ◽  
Author(s):  
M.J. Uddin ◽  
W.A. Khan ◽  
O. Anwar Bég ◽  
A. I. M. Ismail
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Radiative Heat ◽  
Free Stream ◽  
Volume Fraction ◽  
Slip Flow ◽  
Velocity Slip ◽  
Flux Boundary Condition ◽  
Transfer Rates ◽  
Special Cases

We present a mathematical model and numerical simulation of the unsteady 2-D g-jitter-free and forced the convective flow of water-based nanofluid from a flat plate, considering both the velocity slip and thermal slip conditions imposed on the wall of the plate. The Darcian model is used, and both cases of a calm and moving free stream are considered. In place of the extensively used linearly varying radiative heat flux, the nonlinearly varying heat flux calculation is applied to produce practically useful results. Further, we incorporate the “zero mass flux boundary condition” which is believed to be more realistic than the earlier extensively used “actively” controlled model. The parameter influences the non-dimensional velocity, temperature, nanoparticle volume fraction, skin friction and heat transfer rates are visualized graphically and discussed in detail. Special cases of the results are benchmarked with those existing in the literature, and a good arrangement is obtained. It is found that the rate of heat transfer is lower for the calm free stream rather than the moving free stream.

scholarly journals Mathematical Modelling of Radiative Hydromagnetic Thermosolutal Nanofluid Convection Slip Flow in Saturated Porous Media

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammed Jashim Uddin ◽  
Osman Anwar Bég ◽  
Ahmad Izani Md. Ismail
Keyword(s):  
Heat Flux ◽  
Porous Media ◽  
Radiative Heat ◽  
Slip Flow ◽  
Velocity Slip ◽  
Darcy Number ◽  
Radiative Heat Flux ◽  
Force Model ◽  
Radiation Processing ◽  
Convective Boundary

High temperature thermal processing of nanomaterials is an active area of research. Many techniques are being investigated to manipulate properties of nanomaterials for medical implementation. In this paper, we investigate thermal radiation processing of a nanomaterial fluid sheet extruded in porous media. A mathematical model is developed using a Darcy drag force model. Instead of using linear radiative heat flux, the nonlinear radiative heat flux in the Rosseland approximation is taken into account which makes the present study more meaningful and practically useful. Velocity slip and thermal and mass convective boundary conditions are incorporated in the model. The Buongiornio nanofluid model is adopted wherein Brownian motion and thermophoresis effects are present. The boundary layer conservation equations are transformed using appropriate similarity variables and the resulting nonlinear boundary value problem is solved usingMaple 14which uses the Runge-Kutta-Fehlberg fourth fifth order numerical method. Solutions are validated with previous nonmagnetic and nonradiative computations from the literature, demonstrating excellent agreement. The influence of Darcy number, magnetic field parameter, hydrodynamic slip parameter, convection-conduction parameter, convection-diffusion parameter, and conduction-radiation parameter on the dimensionless velocity, temperature, and nanoparticle concentration fields is examined in detail. Interesting patterns of relevance are observed to improve manufacturing of nanofluids.

scholarly journals MHD Partial Slip Flow and Heat Transfer of Nanofluids through a Porous Medium Over a Stretching Sheet with Convective Boundary Condition

2020 ◽  
Vol 12 (1) ◽  
pp. 39-59
Author(s):  
Yohannes Yirga
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Slip Flow ◽  
Velocity Slip ◽  
Partial Slip ◽  
Slip Parameter ◽  
Convective Boundary ◽  
Porosity Parameter ◽  
Flow And Heat Transfer ◽  
Convective Parameter

This paper investigates the boundary layer analysis for magnetohydrodynamic partial slip flow and heat transfer of nanofluids through porous media over a stretching sheet with convective boundary condition. Four types of nanoparticles, namely copper, alumina, copper oxide and titanium oxide in the ethylene glycol (50%, i.e., Pr = 29.86) and water (i.e., Pr = 6.58) based fluids are studied. The governing highly nonlinear and coupled partial differential equations are solved numerically using fourth order Runge-Kutta method with shooting techniques. The velocity and temperature profiles are obtained and utilized to compute the skin friction coefficient and local Nusselt number for different values of the governing parameters viz. nanoparticle volume fraction parameter, magnetic field parameter, porosity parameter, velocity slip parameter and convective parameter. It is found that the velocity distribution of the nanofluids is a decreasing function of the magnetic parameter, porosity parameter, and velocity slip parameter. However, temperature of the nanofluids is an increasing function of magnetic field parameter, nanoparticle volume fraction parameter, porosity parameter, velocity slip parameter and convective parameter. The flow and heat transfer characteristics of the four nanofluids are compared. Moreover, comparison of the numerical results is made with previously published works for special cases and an excellent agreement is found.  Keywords: Magnetohydrodynamics, Partial Slip, Porous medium, Convective boundary, Nanofluid.

Analytic Solution of Gaseous Slip Heat Transfer in Micro-Channel

2008 ◽  
Author(s):  
Tiantian Zhang ◽  
Li Jia ◽  
Zhicheng Wang ◽  
Yan Li ◽  
Xing Li
Keyword(s):  
Heat Transfer ◽  
Superposition Principle ◽  
Slip Flow ◽  
Velocity Slip ◽  
Flow Region ◽  
Constant Heat Flux ◽  
Viscous Heating ◽  
Parallel Plates ◽  
Flux Boundary Condition ◽  
Microscale Effect

2-dimensional steady laminar fully-developed convective heat transfer between two parallel plates with constant heat flux boundary condition in slip flow region was solved analytically by using a new method based on superposition principle. Velocity slip, temperature jump at the wall and viscous heating effect were considered in the calculation. The solution method is verified for the cases where microscale effect is neglected (Kn = 0). Both the heating case and the cooling case were discussed. The effect of viscous heating on temperature and heat transfer was analyzed. The effect of Brinkman number and the Knudsen number on Nusselt number which express the heat transfer performance were analyzed systemically.

scholarly journals Partial Slip Flow and Heat Transfer over a Stretching Sheet in a Nanofluid

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Rajesh Sharma ◽  
Anuar Ishak ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Stretching Sheet ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Slip Flow ◽  
Velocity Slip ◽  
Skin Friction Coefficient ◽  
Partial Slip ◽  
Flow And Heat Transfer

The boundary layer flow and heat transfer of a nanofluid over a stretching sheet are numerically studied. Velocity slip is considered instead of no-slip condition at the boundary as is usually appears in the literature. The governing partial differential equations are transformed into ordinary ones using a similarity transformation, before being solved numerically. Numerical solutions of these equations are obtained using finite element method (FEM). The variations of velocity and temperature inside the boundary layer as well as the skin friction coefficient and the heat transfer rate at the surface for some values of the governing parameters, namely, the nanoparticle volume fraction and the slip parameter are presented graphically and discussed. Comparison with published results for the regular fluid is presented and it is found to be in excellent agreement.

High Order Slip and Thermal Creep Effects in Micro Channel Natural Convection

2010 ◽  
Author(s):  
Hamid Niazmand ◽  
Behnam Rahimi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Temperature Jump ◽  
Slip Flow ◽  
Velocity Slip ◽  
Thermal Creep ◽  
Transfer Rates ◽  
Thermal Fields ◽  
Slip Flow Regime ◽  
Rarefaction Effects

Developing natural convection gaseous flows in an open-ended parallel plate vertical microchannel with isothermal wall conditions are numerically investigated to analyze the rarefaction effects on heat transfer and flow characteristics in slip flow regime. The Navier-Stokes and energy equations are solve by a control volume technique subject to higher-order temperature jump and velocity slip conditions including thermal creep effects. The flow and thermal fields in the entrance and fully developed regions along with the axial variations of velocity slip, temperature jump, and heat transfer rates are examined in detail. It is found that rarefaction effects significantly influence the flow and thermal fields such that mass flow and heat transfer rates are increased considerably as compared to the continuum regime. Furthermore, thermal creep contribution to the velocity slip is found to be dominant close to the channel inlet and vanishes in the fully developed region, while velocity slip approaches a finite value there. Both Mass flow rate and thermal entrance length increase with increasing Knudsen number in slip flow regime.

scholarly journals Control temperature fluctuations in two-phase CuO-water nanofluid by transfiguration of the enclosures

2020 ◽  
pp. 334-334
Author(s):  
Hadi Pourziaei Araban ◽  
Javad Alinejad ◽  
Ganji Domiri
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Natural Convection ◽  
Heat Transfer Rate ◽  
Wall Temperature ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Temperature Fields ◽  
Two Phase ◽  
Flux Boundary Condition

The innovation of this paper is to simulate two-phase nanofluid natural convection inside the transformable enclosure to control the heat transfer rate under different heat flux. Heat transfer of a two-phase CuO-water nanofluid in an enclosure under different heat flux has many industrial applications including energy storage systems, thermal control of electronic devices and cooling of radioactive waste containers. The Lattice Boltzmann Method based on the D2Q9 method has been utilized for modeling velocity and temperature fields. Streamlines, isotherms and nanoparticle volume fraction, have been investigated for control the heat transfer rate for several cases. The purpose of this feasibility study is to achieve uniform temperature profiles and Tmax < 50?C under different heat flux. Natural convection heat transfer in the rectangular and parallelogram enclosures with positive and negative angular adiabatic walls were simulated. The average wall temperature under heat flux boundary condition has been studied to predict optimal levels of effective factors to control the maximum wall temperature. The results illustrated parallelogram enclosures with positive angle of case 1 and case 3 and 4 with rectangular enclosures were best cases for considering physical conditions. Average of temperature for these cases were 37.9, 29.7 and 38.2, respectively.

Heat and mass transfer characteristics of MHD three-dimensional flow over a stretching sheet filled with water-based alumina nanofluid

2018 ◽  
Vol 28 (3) ◽  
pp. 532-546 ◽  
Author(s):  
P. Sudarsan A. Reddy ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Content Type ◽  
Transfer Rates ◽  
Alumina Nanofluid

Purpose This paper aims to understand the influence of velocity slip, nanoparticle volume fraction, chemical reaction and non-linear thermal radiation on MHD three-dimensional heat and mass transfer boundary layer flow over a stretching sheet filled with water-based alumina nanofluid. To get more meaningful results, the authors have taken nonlinear thermal radiation in the heat transfer process. Design/methodology/approach Suitable similarity variables are introduced to convert governing partial differential equations into the set of ordinary differential equations, and are solved numerically using a versatile, extensively validated finite element method with Galerkin’s weighted residual simulation. The velocity, temperature and concentration profiles of nanoparticles as well as skin friction coefficient, Nusselt number and Sherwood number for different non-dimensional parameters such as volume fraction, magnetic, radiation and velocity slip parameters as well as the Prandtl number are examined in detail, and are presented through plots and tables. Findings It is noticed that the rate of heat transfer enhances with higher values of nanoparticle volume fraction parameter. It is worth mentioning that the heat transfer rates improve as the values of increase. Increasing values of M, R, θw and β decelerates the thickness of the thermal boundary layer in the fluid regime. The heat transfer rates decelerate as the values of suction parameter increase. Originality/value The authors have written this paper based on the best of their knowledge on heat and mass transfer analysis of nanofluids. The information in this paper is new and not copied from any other sources.

Slip Flow Heat Transfer in Annular Microchannels With Constant Heat Flux

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Zhipeng Duan ◽  
Y. S. Muzychka
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Knudsen Number ◽  
Temperature Jump ◽  
Slip Flow ◽  
Velocity Slip ◽  
Heat Transfer Characteristics ◽  
Uniform Wall ◽  
Flow Heat ◽  
Uniform Wall Heat Flux

Microscale fluid dynamics has received intensive interest due to the emergence of microelectromechanical systems technology. When the mean free path of the gas is comparable to the channel’s characteristic dimension, the continuum assumption is no longer valid and velocity slip and temperature jump may occur at the duct walls. Slip flow heat transfer in annular microchannels has been examined. The effects of velocity slip and temperature jump on the hydrodynamically and thermally fully developed heat transfer characteristics for laminar flow have been studied analytically. The analysis is carried out for both uniform wall heat flux on one wall, adiabatic on the other wall, and uniform wall heat flux on both walls. The results indicate that the slip flow Nusselt numbers are lower than those for continuum flow and decrease with an increase in Knudsen number for most practical engineering applications. The effects of Knudsen number, radius ratio, and heat flux ratio on heat transfer characteristics are discussed, respectively.

Vapor Bubble Interaction With a Superheated Wall

2017 ◽  
Author(s):  
M. Wasy Akhtar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Vapor Bubble ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Saturation Temperature ◽  
Bubble Wall ◽  
Initial Flow ◽  
Transfer Rates ◽  
Wall Interaction

Sliding bubbles are known to augment heat transfer rates on the surface on which they slide. The pre-cursor problem — the bubble approaching an inclined superheated wall provides the initial flow and thermal field for the sliding bubble problem. An FC-87 vapor bubble rising in a thermally stratified flow field is simulated along with the bubble wall interaction effects. The simulation is conducted on a dynamic octree grid for improved accuracy and efficiency. The evolution of the bubble shape and the wake behind the rising bubble is captured in a three-dimensional model, which takes into account bubble growth due to superheat at the liquid-vapor interface and the effect of interface heat flux on the local saturation temperature. After the first bubble-wall interaction, a microlayer tens of microns thick forms between the bubble and the wall; a thermal wake develops behind the bubble as it begins to slide against the wall. The predicted shapes, Re and Weber numbers and microlayer thicknesses show excellent agreement in comparison to experimental data from other researchers. Evolution of the flow and temperature fields were examined with the aid of contours of vapor volume fraction and iso-lines of mixture temperature superimposed on three-dimensional shapes of the bubble. Overall bubble dynamics and microlayer dynamics, including microlayer thickness and microlayer heat flux, are presented as functions of time. Using the wall, microlayer and wake heat transfer rates, an enhancement of the total wall heat flux was found to be on the order of 6 times the background heat flux. This work describes the bubble evolution through the first rebounding in detail, but the dynamic octree adaption algorithm lends itself to study of the long-term dynamics well into the sliding regime. The technique can also be used to investigate other multiphase flow phenomena — especially bubble coalescence and breakup.

Analysis of flow and heat transfer over stretching/shrinking and porous surfaces

2021 ◽  
pp. 875608792110258
Author(s):  
Azhar Ali ◽  
Dil Nawaz Khan Marwat ◽  
Aamir Ali
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Current Model ◽  
Uniform Heat Flux ◽  
Similarity Transformations ◽  
Flow And Heat Transfer ◽  
Special Cases ◽  
Porous Surfaces

Flows and heat transfer over stretching/shrinking and porous surfaces are studied in this paper. Unusual and generalized similarity transformations are used for simplifying governing equations. Current model includes all previous cases of stretched/shrunk flows with thermal effects discussed so far. Moreover, we present three different cases of thermal behavior (i) prescribed surface temperature (ii) Variable/uniform convective heat transfer at plat surface and (iii) prescribed variable/uniform heat flux. Stretching/shrinking velocity Uw(x), porosity [Formula: see text], heat transfer [Formula: see text], heat flux [Formula: see text] and convective heat transfer at surface are axial coordinate dependent. Boundary layer equations and boundary conditions are transformed into nonlinear ODEs by introducing unusual and generalized similarity transformations for the variables. These simplified equations are solved numerically. Final ODEs represent suction/injection, stretching/shrinking, temperature, heat flux, convection effects and specific heat. This current problem encompasses all previous models as special cases which come under the scope of above statement (title). The results of classical models are scoped out as a special case by assigning proper values to the parameters. Numerical result shows that the dual solutions can be found for different possible values of the shrinking parameter. A stability analysis is accomplished and apprehended in order to establish a criterion for determining linearly stable and physically compatible solutions. The significant features and diversity of the modeled equations are scrutinized by recovering the previous problems of fluid flow and heat transfer from a uniformly heated sheet of variable (uniform) thickness with variable (uniform) stretching/shrinking and injection/suction velocities.

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