scholarly journals Cooling Intensification of a Continuously Moving Stretching Surface Using Different Types of Nanofluids

2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
M. B. Akgül ◽  
M. Pakdemirli

The effect of different types of nanoparticles on the heat transfer from a continuously moving stretching surface in a concurrent, parallel free stream has been studied. The stretching surface is assumed to have power-law velocity and temperature. The governing equations are converted into a dimensionless system of equations using nonsimilarity variables. Resulting equations are solved numerically for various values of flow parameters. The effect of physical quantities on the temperature profiles is discussed in detail.

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Tapas Ray Mahapatra ◽  
Sabyasachi Mondal ◽  
Dulal Pal

An analysis is made on the study of two-dimensional MHD (magnetohydrodynamic) boundary-layer stagnation-point flow of an electrically conducting power-law fluid over a stretching surface when the surface is stretched in its own plane with a velocity proportional to the distance from the stagnation-point in the presence of thermal radiation and suction/injection. The paper examines heat transfer in the stagnation-point flow of a power-law fluid except when the ratio of the free stream velocity and stretching velocity is equal to unity. The governing partial differential equations along with the boundary conditions are first brought into a dimensionless form and then the equations are solved by Runge-Kutta fourth-order scheme with shooting techniques. It is found that the temperature at a point decreases/increases with increase in the magnetic field when free stream velocity is greater/less than the stretching velocity. It is further observed that for a given value of the magnetic parameter M, the dimensionless rate of heat transfer at the surface and |θ′(0)| decreases/increases with increase in the power-law index n. Further, the temperature at a point in the fluid decreases with increase in the radiation parameter NR when free stream velocity is greater/less than the stretching velocity.


Author(s):  
M. Ismoen ◽  
M. F. Karim ◽  
R. Mohamand ◽  
R. Kandasamy

<p class="TRANSAffiliation"><span>The similarity and non-similarity analysis are presented to investigate the effect of buoyancy force on the steady flow and heat transfer of fluid past a heated wedge. The fluid is assumed to be a Newtonian, viscous and incompressible. The wall of the wedge is an impermeable with power law free stream velocity and a wall temperature. Due to the effect of a buoyancy force, a power law of free stream velocity and wall temperature, then the flow field is similar when <em>n = 2m - 1</em>, otherwise is non-similar when <em>n ≠ 2m - 1</em>. The governing boundary layer equations are written into dimensionless forms of ordinary differential equations by means of Falkner-Skan transformation. The resulting ordinary differential equations are solved by Runge-Kutta Gill with shooting method for finding a skin friction and a rate of heat transfer. The effects of buoyancy force and non-uniform wall temperature parameters on the dimensionless velocity and temperature profiles are shown graphically. Comparisons with previously published works are performed and excellent agreement between the results is obtained. The conclusion is drawn that the flow field and temperature profiles are significantly influenced by these parameters.</span></p>


2018 ◽  
Vol 7 (4.35) ◽  
pp. 148 ◽  
Author(s):  
Nur Irmawati Om ◽  
Rozli Zulkifli ◽  
P. Gunnasegaran

The influence of utilizing different nanofluids types on the liquid cold plate (LCP) is numerically investigated. The thermal and fluid flow performance of LCP is examined by using pure ethylene glycol (EG), Al2O3-EG and CuO-EG. The volume fraction of the nanoparticle for both nanofluid is 2%. The finite volume method (FVM) has been used to solved 3-D steady state, laminar flow and heat transfer governing equations. The presented results indicate that Al2O3-EG able to provide the lowest surface temperature of the heater block followed by CuO-EG and EG, respectively. It is also found that the pressure drop and friction factor are higher for Al2O3-EG and CuO-EG compared to the pure EG.


2020 ◽  
Vol 41 (11) ◽  
pp. 1707-1722
Author(s):  
M. H. A. Kamal ◽  
N. A. Rawi ◽  
A. Ali ◽  
S. Shafie

Abstract The unsteady double diffusion of the boundary layer with the nanofluid flow near a three-dimensional (3D) stagnation point body is studied under a microgravity environment. The effects of g-jitter and thermal radiation exist under the microgravity environment, where there is a gravitational field with fluctuations. The flow problem is mathematically formulated into a system of equations derived from the physical laws and principles under the no-slip boundary condition. With the semi-similar transformation technique, the dimensional system of equations is reduced into a dimensionless system of equations, where the dependent variables of the problem are lessened. A numerical solution for the flow problem derived from the system of dimensionless partial differential equations is obtained with the Keller box method, which is an implicit finite difference approach. The effects studied are analyzed in terms of the physical quantities of principle interest with the fluid behavior characteristics, the heat transfer properties, and the concentration distributions. The results show that the value of the curvature ratio parameter represents the geometrical shape of the boundary body, where the stagnation point is located. The increased modulation amplitude parameter produces a fluctuating behavior on all physical quantities studied, where the fluctuating range becomes smaller when the oscillation frequency increases. Moreover, the addition of Cu nanoparticles enhances the thermal conductivity of the heat flux, and the thermal radiation could increase the heat transfer properties.


2012 ◽  
Vol 03 (05) ◽  
pp. 425-435 ◽  
Author(s):  
Kerehalli Vinayaka Prasad ◽  
Seetharaman Rajeswari Santhi ◽  
Pampanna Somanna Datti

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1959
Author(s):  
Adrian S. Halifi ◽  
Sharidan Shafie ◽  
Norsarahaida S. Amin

The effect of non-Newtonian biomagnetic power-law fluid in a channel undergoing external localised magnetic fields is investigated. The governing equations are derived by considering both effects of Ferrohydrodynamics (FHD) and Magnetohydrodynamics (MHD). These governing equations are difficult to solve due to the inclusion of source term from magnetic equation and the nonlinearity of the power-law model. Numerical scheme of Constrained Interpolation Profile (CIP) is developed to solve the governing equations numerically. Extensive results carried out show that this method is efficient on studying the biomagnetic and non-Newtonian power-law flow. New results show that the inclusion of power-law model affects the vortex formation, skin friction and heat transfer parameter significantly. Regardless of the power-law index, the vortex formation length increases when Magnetic number increases. The effect of this vortex however decreases with the inclusion of power-law where in the shear thinning case, the arising vortex is more pronounced than in the shear thickening case. Furthermore, increasing of power-law index from shear thinning to shear thickening, decreases the wall shear stress and heat transfer parameters. However for high Magnetic number, the wall shear stress and heat transfer parameters increase especially near the location of the magnetic source. The results can be used as a guide on assessing the potential effects of radiofrequency fields (RF) from electromagnetic fields (EMF) exposure on blood vessel.


1965 ◽  
Vol 87 (3) ◽  
pp. 349-352 ◽  
Author(s):  
B. T. Chao

An analysis is presented for the title problem based on the governing conservation equations and the measured free-stream temperature variation with time as reported by Levy and Potter. The results compare very favorably with the published data. Several temperature profiles are illustrated which confirm a posteriori the validity of the thin thermal boundary-layer assumption used.


2017 ◽  
Vol 1 (2) ◽  
Author(s):  
B. C. Prasannakumara ◽  
B. J. Gireesha ◽  
M. R. Krishnamurthy ◽  
Rama Subba Reddy Gorla

AbstractWe analyzed the effects of Biot number and non-uniform heat source/sink on boundary layer flow and nonlinear radiative heat transfer of fluid particle suspension over an unsteady stretching surface embedded in a porous medium with nanoparticles. We considered conducting dust particles embedded with -water nanopartcles. The governing equations are transformed into nonlinear ordinary differential equations by using local similarity transformations and solved numerically using Runge–Kutta-Fehlberg-45 order method along with shooting technique. The effects of non-dimensional parameters on velocity and temperature profiles for fluid phase and dust phase are discussed and presented through graphs. Also, friction factor and Nusselt number are discussed and presented through graphs. Comparisons of the present study were made with existing studies under some special assumptions. The present results have an excellent agreement with existing studies. Results indicated that the enhancement in fluid particle interaction parameter increases the heat transfer rate and depreciates the wall friction. Also, radiation parameter has the tendency to increase the temperature profiles of the dusty nanofluid.


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