scholarly journals Magnetohydrodynamic Three Dimensional Flow and Heat Transfer Past a Vertical Porous Plate Through a Porous Medium with Periodic Suction

1970 ◽  
Vol 46 (4) ◽  
pp. 465-474 ◽  
Author(s):  
SS Das ◽  
M Mitra ◽  
PK Mishra
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Flow Field ◽  
Prandtl Number ◽  
Skin Friction ◽  
Magnetic Parameter ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Suction Parameter ◽  
Permeability Parameter

This paper analyzes the effect of magnetic field and the permeability of the medium on the three dimensional flow of a viscous incompressible electrically conducting fluid through a porous medium bounded by an infinite vertical porous plate in presence of periodic suction and a transverse magnetic field. The governing equations for the velocity and temperature of the flow field are solved employing perturbation technique and the effects of the pertinent parameters such as magnetic parameter (M), suction parameter (α), permeability parameter (Kp), Reynolds number (Re) and Prandtl number (Pr) on the velocity field, temperature field, skin friction and the rate of heat transfer are discussed with the help of figures and tables. It is observed that both magnetic parameter and the permeability parameter have accelerating effect on the velocity of the flow field. The effect of growing Prandtl number/suction parameter/ Reynolds number is to enhance the temperature of the flow field at all points while a growing magnetic parameter has retarding effect on the temperature field. The magnetic parameter increases the x-component of skin friction and reduces the magnitude of z-component of skin friction at the wall while the permeability parameter shows the reverse effect on both the components of skin friction. The rate of heat transfer at the wall grows as we increase the magnetic parameter or suction parameter or Prandtl number in the flow field and the effect reverses with the increase of the permeability parameter. Key words: MHD; Three dimensional flow; Heat transfer; Vertical plate; Porous medium; Periodic suction   DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9593 BJSIR 2011; 46(4): 465-474

scholarly journals Effect of constant suction and injection on MHD three dimensional couette flow and heat transfer through a porous medium

2010 ◽  
Vol 6 (1) ◽  
pp. 41-51 ◽  
Author(s):  
S. S. Das
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Temperature Field ◽  
Skin Friction ◽  
Couette Flow ◽  
Three Dimensional ◽  
Injection Parameter ◽  
Constant Suction ◽  
Permeability Parameter

The objective of this paper is to analyzethe effect of constant suction and sinusoidal injection on three dimensional couette flow of a viscous incompressible electrically conducting fluid through a porous medium between two infinite horizontal parallel porous flat plates in presence of a transverse magnetic field. The stationary plate and the plate in uniform motion are, respectively, subjected to a transverse sinusoidal injection and uniform suction of the fluid .The flow becomes three dimensional due to this type of injection velocity distribution. The governing equations of the flow field are solved by using series expansion method and the expressions for the velocity field, the temperature field, skin friction and the rate of heat transfer in terms of Nusselt number are obtained. The effects of the flow parameters on the velocity field, temperature field, skin friction and the Nusselt number have been studied and analyzed with the help of figures and tables. It is observed that a growing magnetic parameter (M) retards the main velocity (u) and accelerates the cross flow velocity (w1) of the flow field and a growing permeability parameter (Kp) or suction / injection parameter (Re) reverses the effect. Both Prandtl number (Pr) and the suction / injection parameter have retarding effect on the temperature field. Further, a growing suction / injection parameter diminishes both the components of skin friction at the wall while the permeability parameter enhances the x-component and reduces the z-component of the skin friction at the wall. The effect of increasing permeability parameter is to enhance the magnitude of rate of heat transfer at the wall while a growing Prandtl number (Pr) reverses the effect.Keywords: MHD; couette flow; heat transfer; suction; sinusoidal injection; porous mediumDOI: 10.3329/jname.v5i2.2570Journal of Naval Architecture and Marine Engineering 6(1)(2009) 41-51 

scholarly journals Hydromagnetic Three Dimensional Couette Flow and Heat Transfer

1970 ◽  
Vol 5 (1) ◽  
pp. 1-10 ◽  
Author(s):  
SS Das ◽  
M Mohanty ◽  
JP Panda ◽  
SK Sahoo
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Temperature Field ◽  
Flow Field ◽  
Skin Friction ◽  
Couette Flow ◽  
Three Dimensional ◽  
Flat Plates ◽  
Suction Parameter ◽  
Retarding Effect

This paper is concerned with the theoretical analysis of three dimensional couette flow of a viscous incompressible electrically conducting fluid between two infinite horizontal parallel porous flat plates in presence of a transverse magnetic field. The stationary plate and the plate in uniform motion are, respectively, subjected to a transverse sinusoidal injection and uniform suction of the fluid. The governing equations of the flow field are solved by using series expansion method and the expressions for the velocity field, the temperature field, skin friction and heat flux in terms of Nusselt number are obtained. The effects of the flow parameters on the velocity, temperature, skin friction and heat flux have been studied and analyzed with the help of figures and tables. It is observed that the magnetic parameter (M) has a retarding effect on the main velocity (u) and an accelerating effect on the cross velocity (w1) of the flow field. The suction parameter (Re) has a retarding effect on the main velocity as well as on the temperature field. The Prandtl number (Pr) reduces the temperature of the flow field and increases the rate of heat transfer at the wall (Nu). The effect of suction parameter is to reduce the x-component of skin friction and to enhance the magnitude of z-component of the skin friction at the wall. This problem is very much significant in view of its several engineering, geophysical and industrial applications.Keywords: Hydromagnetic, couette flow, heat transfer, three dimensions doi:10.3329/jname.v5i1.1784 Journal of Naval Architecture and Marine Engineering Vol. 5, No. 1 (June, 2008) 1-10.

scholarly journals Computational Study of Flow and Heat Transfer With Anti Cross-Flows (ACF) Jet Impingement Cooling for Different Heights of Corrugate

2017 ◽  
Author(s):  
Radheesh Dhanasegaran ◽  
Ssheshan Pugazhendhi
Keyword(s):  
Heat Transfer ◽  
Skin Friction ◽  
Heat Transfer Performance ◽  
Computational Study ◽  
Three Dimensional ◽  
Cross Flow ◽  
Transfer Performance ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Plate Spacing

In the present study, a flow visualization and heat transfer investigation is carried out computationally on a flat plate with 10×1 array of impinging jets from a corrugated plate. This corrugated structure is an Anti-Cross Flow (ACF) technique which is proved to nullify the negative effects of cross-flow thus enhancing the overall cooling performance. Governing equations are solved using k-ω Shear Stress Transport (SST) turbulence model in commercial code FLUENT. The parameter variation considered for the present study are (i) three different heights of ACF corrugate (C/D = 1, 2 & 3) and (ii) two different jet-to-target plate spacing (H/D = 1 & 2). The dependence of ACF structure performance on the corrugate height (C/D) and the flow structure has been discussed in detail, therefore choosing an optimum corrugate height and visualizing the three-dimensional flow phenomena are the main objectives of the present study. The three-dimensional flow separation and heat transfer characteristics are explained with the help of skin friction lines, upwash fountains, wall eddies, counter-rotating vortex pair (CRVP), and plots of Nusselt number. It is found that the heat transfer performance is high at larger corrugate heights for both the jet-to-plate spacing. Moreover, the deterioration of the skin friction pattern corresponding to the far downstream impingement zones is greatly reduced with ACF structure, retaining more uniform heat transfer pattern even at low H/D values where the crossflow effects are more dominant in case of the conventional cooling structure. In comparison of the overall heat transfer performance the difference between C/D = 3 & C/D = 2 for H/D = 2 is significantly less, thus making the later as the optimal configuration in terms of reduced channel height.

scholarly journals Radiation Effect On Three Dimensional Vertical Channel Flow Through Porous Medium

2015 ◽  
Vol 20 (4) ◽  
pp. 817-833
Author(s):  
M. Guria
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Prandtl Number ◽  
Perturbation Technique ◽  
Vertical Channel ◽  
Temperature Fields ◽  
Shear Stresses ◽  
Radiation Parameter ◽  
Permeability Parameter ◽  
Primary Velocity

Abstract The flow of a viscous incompressible fluid through a vertical channel in the presence of radiation immersed in a porous medium has been studied. Approximate solutions have been obtained for the velocity and temperature fields, shear stresses and rate of heat transfer using the perturbation technique. It is found that the primary velocity decreases with an increase in the radiation parameter as well as the Prandtl number for cooling of the plate. It is also found that with an increase in the permeability parameter, the primary velocity increases for cooling of the plate. The magnitude of the secondary velocity decreases near the plate y = 0 and increases near the plate y = d with an increase in the permeability parameter. The temperature distribution decreases with an increase of the radiation parameter as wall as the Prandtl number for cooling of the plate. The shear stresses and the rate of heat transfer, which are of physical interest, are presented in the form of tables.

Effects of Catalytic and Dry Low NOx Combustor Turbulence on Endwall Heat Transfer Distributions

2005 ◽  
Vol 127 (4) ◽  
pp. 414-424 ◽  
Author(s):  
F. E. Ames ◽  
P. A. Barbot ◽  
C. Wang
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
Catalytic Combustor ◽  
Vortex Systems

Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0% for the mock catalytic combustor condition to 14% for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for both the mock catalytic and DLN combustor cases. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95% span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

Piezoelectric Fans: Heat Transfer Enhancements for Electronics Cooling

2008 ◽  
Author(s):  
James Petroski ◽  
Mehmet Arik ◽  
Mustafa Gursoy
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Field ◽  
Heat Sink ◽  
Three Dimensional ◽  
Electronics Cooling ◽  
Coefficient Of Performance ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Piezoelectric Fans

Piezoelectric fans have been investigated for electronics cooling over the last decade. The primary usage or method has been to place the vibrating fan near the surface to be cooled. The piezofan used in the current study is composed of a piezo actuator attached to a flexible metal beam. It is operated at up to 120VAC and at 60 Hz. While most of the research in the literature focused on cooling bare surfaces, larger heat transfer rates are of interest in the present study. A proposed system of piezoelectric fans and heat sink is presented as a more efficient method of system cooling with these fans. In this paper, a heat sink and piezoelectric fan system demonstrated a capability of cooling an area of about 75 cm2 (about 1 C/W) where electronic assemblies can be mounted. The heat sink not only provides surface area, but also flow shaping for the unusual three-dimensional flow field of the fans. A volumetric coefficient of performance (COPv) is proposed, which allows a piezofan and heat sink system volume to be compared against the heat dissipating capacity of a similar heat sink of the same volume for natural convection. A piezofan system is shown to have a COPv of five times of a typical natural convection solution. The paper will further discuss the effect of nozzles in flow shaping obtained via experimental and computational studies. A three-dimensional flow field of the proposed cooling scheme with a piezofan is obtained via laser Doppler anemometry (LDA) flow visualization method. Velocities at the heat sink in the order of 1.5 m/s were achieved through this critical shaping. Finally, the overall system characterization to different heat loads and fan amplitudes will be discussed.

Effects of Catalytic and Dry Low NOx Combustor Turbulence on Endwall Heat Transfer Distributions

2003 ◽  
Author(s):  
F. E. Ames ◽  
P. A. Barbot ◽  
C. Wang
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
Catalytic Combustor ◽  
Vortex Systems

Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0 percent for the mock catalytic combustor condition to 14 percent for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for both the mock catalytic and DLN combustor cases. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95 percent span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

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