Erratum: “Turbulent Transport to a Rotating Cylinder for Large Prandtl or Schmidt Numbers” (Journal of Heat Transfer, 1975, 97, pp. 594–597)

1976 ◽  
Vol 98 (2) ◽  
pp. 302-302
Author(s):  
R. N. Smith ◽  
R. Greif
Keyword(s):  
Heat Transfer ◽  
Turbulent Transport ◽  
Rotating Cylinder ◽  
Schmidt Numbers

Turbulent Transport to a Rotating Cylinder for Large Prandtl or Schmidt Numbers

1975 ◽  
Vol 97 (4) ◽  
pp. 594-597 ◽  
Author(s):  
R. N. Smith ◽  
R. Greif
Keyword(s):  
Experimental Data ◽  
Mass Transport ◽  
Richardson Number ◽  
Turbulent Transport ◽  
Rotating Cylinder ◽  
Mixing Length ◽  
Centrifugal Forces ◽  
Conservation Equations ◽  
Schmidt Numbers

The heat or mass transport to a rotating cylinder is obtained by solving the conservation equations for large Prandtl or Schmidt numbers. A modified mixing length, which includes the effect of centrifugal forces in terms of the Richardson number, is used. Explicit relations are presented for the heat or mass transport and a comparison is made with the experimental data over a range of Prandtl and Schmidt numbers from 190 to 11,000.

Turbulent Transport in Pin Fin Arrays: Experimental Data and Predictions

2005 ◽  
Author(s):  
F. E. Ames ◽  
L. A. Dvorak
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Boundary Layers ◽  
Fluid Dynamic ◽  
Turbulent Transport ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Pin Fin ◽  
Pin Fin Arrays

The objective of this research has been to experimentally investigate the fluid dynamics of pin fin arrays in order to clarify the physics of heat transfer enhancement and uncover problems in conventional turbulence models. The fluid dynamics of a staggered pin fin array have been studied using hot wire anemometry with both single and x-wire probes at array Reynolds numbers of 3000; 10,000; and 30,000. Velocity distributions off the endwall and pin surface have been acquired and analyzed to investigate turbulent transport in pin fin arrays. Well resolved 3-D calculations have been performed using a commercial code with conventional two-equation turbulence models. Predictive comparisons have been made with fluid dynamic data. In early rows where turbulence is low, the strength of shedding increases dramatically with increasing in Reynolds numbers. The laminar velocity profiles off the surface of pins show evidence of unsteady separation in early rows. In row three and beyond laminar boundary layers off pins are quite similar. Velocity profiles off endwalls are strongly affected by the proximity of pins and turbulent transport. At the low Reynolds numbers, the turbulent transport and acceleration keep boundary layers thin. Endwall boundary layers at higher Reynolds numbers exhibit very high levels of skin friction enhancement. Well resolved 3-D steady calculations were made with several two-equation turbulence models and compared with experimental fluid mechanic and heat transfer data. The quality of the predictive comparison was substantially affected by the turbulence model and near wall methodology.

Magnetohydrodynamic Mixed-Convective Flow and Heat and Mass Transfer Past a Vertical Plate in a Porous Medium With Constant Wall Suction

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
O. D. Makinde ◽  
P. Sibanda
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Vertical Plate ◽  
Skin Friction Coefficient ◽  
Convection Flow ◽  
Convection Boundary Layer ◽  
Flow Equations ◽  
Schmidt Numbers ◽  
Layer Flow ◽  
Mixed Convective Flow

The problem of steady laminar hydromagnetic heat transfer by mixed convection flow over a vertical plate embedded in a uniform porous medium in the presence of a uniform normal magnetic field is studied. Convective heat transfer through porous media has wide applications in engineering problems such as in high temperature heat exchangers and in insulation problems. We construct solutions for the free convection boundary-layer flow equations using an Adomian–Padé approximation method that in the recent past has proven to be an able alternative to the traditional numerical techniques. The effects of the various flow parameters such as the Eckert, Hartmann, and Schmidt numbers on the skin friction coefficient and the concentration, velocity, and temperature profiles are discussed and presented graphically. A comparison of our results with those obtained using traditional numerical methods in earlier studies is made, and the results show an excellent agreement. The results demonstrate the reliability and the efficiency of the Adomian–Padé method in an unbounded domain.

Endwall Heat Transfer Measurements in a Staggered Pin Fin Array With an Adiabatic Pin

2007 ◽  
Author(s):  
Forrest E. Ames ◽  
Chad A. Nordquist ◽  
Lindsay A. Klennert
Keyword(s):  
Heat Transfer ◽  
Turbulent Transport ◽  
Infrared Camera ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Skin Friction Coefficient ◽  
Vortex System ◽  
Flow Acceleration ◽  
Pin Fin ◽  
Pin Fin Array

Full surface endwall heat transfer distributions have been acquired in a staggered pin fin array with the use of an infrared camera. Values are presented at Reynolds numbers of 3000, 10,000 and 30,000 based on pin diameter and average velocity through adjacent pins. Average endwall Nusselt numbers agree closely with archival values at each Reynolds number. Locally averaged heat transfer levels show a substantial increase from the inlet through the first few rows and finally a nearly streamwise periodic condition in the second half of the eight row geometry. Increasing levels of heat transfer in the inlet region can be attributed to the leading edge vortex system, flow acceleration around pins, and the generation of turbulence. Distributions of turbulence intensity and turbulent scale are shown to help document the turbulent transport conditions through the array. Detailed endwall Nusselt number distributions are presented and compared at the three Reynolds numbers for the first four and last four rows. These detailed heat transfer distributions highlight the influence of the horseshoe vortex system in the entrance region and the wake generated turbulence throughout the pin fin array. Local velocity and turbulence distributions are presented together with local Stanton number and skin friction coefficient data to examine the aggressive nature of the turbulent mixing.

Control of Turbulent Transport: Less Friction and More Heat Transfer

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Nobuhide Kasagi ◽  
Yosuke Hasegawa ◽  
Koji Fukagata ◽  
Kaoru Iwamoto
Keyword(s):  
Heat Transfer ◽  
Heat Transport ◽  
Turbulent Transport ◽  
Scalar Fields ◽  
Wall Friction ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Control Input ◽  
Divergence Free Vector ◽  
Wide Range

Because of the importance of fundamental knowledge on turbulent heat transfer for further decreasing entropy production and improving efficiency in various thermofluid systems, we revisit a classical issue whether enhancing heat transfer is possible with skin friction reduced or at least not increased as much as heat transfer. The answer that numerous previous studies suggest is quite pessimistic because the analogy concept of momentum and heat transport holds well in a wide range of flows. Nevertheless, the recent progress in analyzing turbulence mechanics and designing turbulence control offers a chance to develop a scheme for dissimilar momentum and heat transport. By reexamining the governing equations and boundary conditions for convective heat transfer, the basic strategies for achieving dissimilar control in turbulent flow are generally classified into two groups, i.e., one for the averaged quantities and the other for the fluctuating turbulent components. As a result, two different approaches are discussed presently. First, under three typical heating conditions, the contribution of turbulent transport to wall friction and heat transfer is mathematically formulated, and it is shown that the difference in how the local turbulent transport of momentum and that of heat contribute to the friction and heat transfer coefficients is a key to answer whether the dissimilar control is feasible. Such control is likely to be achieved when the weight distributions for the stress and flux in the derived relationships are different. Second, we introduce a more general methodology, i.e., the optimal control theory. The Fréchet differentials obtained clearly show that the responses of velocity and scalar fields to a given control input are quite different due to the fact that the velocity is a divergence-free vector, while the temperature is a conservative scalar. By exploiting this inherent difference, the dissimilar control can be achieved even in flows where the averaged momentum and heat transport equations have the same form.

scholarly journals Transient Heat Transfer in Rotating Cylinder - Thermography Measurement to Analyse Intense Heat Flux Distribution

2008 ◽  
Author(s):  
J.C. Batsale ◽  
J.P. Lasserre ◽  
M. Varenne-Pellegrini ◽  
V. Desormiere ◽  
L. Authesserre ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flux Distribution ◽  
Rotating Cylinder ◽  
Transient Heat Transfer ◽  
Heat Flux Distribution ◽  
Intense Heat
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