Direct Numerical Simulation of Three-Dimensional Flow and Augmented Heat Transfer in a Grooved Channel

1998 ◽  
Vol 120 (3) ◽  
pp. 717-723 ◽  
Author(s):  
M. Greiner ◽  
G. J. Spencer ◽  
P. F. Fischer
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Friction Factor ◽  
Three Dimensional ◽  
Spectral Element ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Number Range ◽  
Dimensional Flow ◽  
Element Technique

Direct numerical simulations of three-dimensional flow and augmented convective heat transfer in a transversely grooved channel are presented for the Reynolds number range 140 < Re < 2000. These calculations employ the spectral element technique. Multiple flow transitions are documented as the Reynolds number increases, from steady two-dimensional flow through broad-banded unsteady three-dimensional mixing. Three-dimensional simulations correctly predict the Reynolds-number-independent friction factor behavior of this flow and quantify its heat transfer to within 16 percent of measured values. Two-dimensional simulations, however, incorrectly predict laminar-like friction factor and heat transfer behaviors.

Two-dimensional and three-dimensional self-sustained flow oscillations in interrupted fin heat exchangers

2006 ◽  
Vol 220 (3) ◽  
pp. 297-306
Author(s):  
G Croce ◽  
P D'Agaro
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Enhancement ◽  
Three Dimensional ◽  
Chaotic Regime ◽  
Flow Structures ◽  
Two Dimensional ◽  
Transfer Enhancement ◽  
Three Dimensional Flow ◽  
Dimensional Flow

A numerical analysis of three-dimensional flow structures in a nominally two-dimensional fin geometry is presented. A sinusoidal louvred fin is considered. The heat transfer enhancement is achieved by combining boundary layer interruptions and vortical structures induced by the corrugation of the base fin. The fin shape and pitch, as well as flow conditions, are representative of typical automotive application. A wide ranging values of Reynolds number are investigated, spanning the steady laminar regime, the unsteady periodic laminar flow, and the chaotic transitional flow. Two- and three-dimensional numerical solutions are compared, looking for the onset of three-dimensional instabilities. At low values of the Reynolds number, up to the steady-unsteady flow transition, the flow is two-dimensional. As soon as unsteady oscillation appears, the simulation results show three-dimensional flow structures, even in a nominally two-dimensional geometry. The typical longitudinal vortex size is evaluated. In the periodic unsteady regime, fully three-dimensional computations yield time-averaged Nusselt number and friction factor significantly higher than those predicted by two-dimensional models. Furthermore, these flow structures induce an early transition from the periodic regime to the chaotic regime. In the chaotic regime, however, the heat transfer enhancement due to the three-dimensional flow structures is much lower.

Two Dimensional Simulations of Enhanced Heat Transfer in an Intermittently Grooved Channel

2000 ◽  
Author(s):  
M. Greiner ◽  
P. F. Fischer ◽  
H. M. Tufo
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Spectral Element ◽  
Local Heat ◽  
Navier Stokes ◽  
Computational Domain ◽  
Two Dimensional ◽  
Number Range ◽  
Element Technique ◽  
Outflow Boundary

Abstract Two-dimensional Navier-Stokes simulations of heat and momentum transport in an intermittently grooved passage are performed using the spectral element technique for the Reynolds number range 600 ≤ Re ≤ 1800. The computational domain has seven contiguous transverse grooves cut symmetrically into opposite walls, followed by a flat section with the same length. Periodic inflow/outflow boundary conditions are employed. The development and decay of unsteady flow is observed in the grooved and flat sections, respectively. The axial variation of the unsteady component of velocity is compared to the local heat transfer, shear stress and pressure gradient. The results suggest that intermittently grooved passages may offer even higher heat transfer for a given pumping power than the levels observed in fully grooved passages.

Simulations of Three-Dimensional Flow and Augmented Heat Transfer in a Symmetrically Grooved Channel

2000 ◽  
Vol 122 (4) ◽  
pp. 653-660 ◽  
Author(s):  
M. Greiner ◽  
R. J. Faulkner ◽  
V. T. Van ◽  
H. M. Tufo ◽  
P. F. Fischer
Keyword(s):  
Three Dimensional ◽  
Spectral Element ◽  
Navier Stokes ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Transverse Grooves ◽  
Flow Transitions ◽  
Element Technique ◽  
Good Agreement

Navier-Stokes simulations of three-dimensional flow and augmented convection in a channel with symmetric, transverse grooves on two opposite walls were performed for 180⩽Re⩽1600 using the spectral element technique. A series of flow transitions was observed as the Reynolds number was increased, from steady two-dimensional flow, to traveling two and three-dimensional wave structures, and finally to three-dimensional mixing. Three-dimensional simulations exhibited good agreement with local and spatially averaged Nusselt number and friction factor measurements over the range 800⩽Re⩽1600. [S0022-1481(00)00904-X]

Heat Transfer and Turbulent Flow Characteristics of Isolated Three-Dimensional Protrusions in Channels

1991 ◽  
Vol 113 (3) ◽  
pp. 597-603 ◽  
Author(s):  
P. T. Roeller ◽  
J. Stevens ◽  
B. W. Webb
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Channel Wall ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Average Heat ◽  
Flow Acceleration ◽  
Dimensional Flow ◽  
Wall Spacing

The flow structure and average heat transfer characteristics of single, isolated three-dimensional protrusions in a flow channel have been investigated experimentally. This configuration has relevance in the electronics industry. The study was designed to identify the influence of the three-dimensional flow around a heated protrusion on its average heat transfer. Heated protrusions varying in width between 0.12 and 1.0 channel widths for a fixed protrusion height and streamwise length were studied in the channel Reynolds number range 500≤Re≤10,000. The channel wall spacing was also varied parametrically between 1.25 and 2.5 streamwise protrusion lengths. The study included both average heat transfer measurements, and detailed local velocity and turbulent flow structure measurements made using laser-Doppler velocimetry. The experimental results show that the Nusselt number increases with both decreasing channel wall spacing and decreasing protrusion width. The increase in heat transfer with decreasing wall spacing is explained by the accelerated flow due to the protrusion-obstructed channel. Increasing Nusselt number with decreasing protrusion width is a result of increased three-dimensional flow and associated turbulent mixing. Both of these flow-related phenomena are illustrated with local mean velocity and turbulence intensity measurements. The presence of recirculation zones both upstream and downstream of the module is revealed. The flow acceleration around the heated protrusions, and three dimensionality of the flow and heat transfer are competing mechanisms; the higher heat transfer due to flow acceleration around the protrusions for larger protrusions goes counter to the trend for higher heat transfer due to increased three-dimensional flow and transport for smaller protrusions. A Nusselt number correlation is developed as a function of channel Reynolds number and protrusion and channel geometric parameters, which describes the tradeoffs discussed.

Two-Dimensional Simulations of Enhanced Heat Transfer in an Intermittently Grooved Channel

2002 ◽  
Vol 124 (3) ◽  
pp. 538-545 ◽  
Author(s):  
M. Greiner ◽  
P. F. Fischer ◽  
H. M. Tufo
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Spectral Element ◽  
Local Heat ◽  
Navier Stokes ◽  
Computational Domain ◽  
Two Dimensional ◽  
Number Range ◽  
Element Technique ◽  
Outflow Boundary

Two-dimensional Navier-Stokes simulations of heat and momentum transport in an intermittently grooved passage are performed using the spectral element technique for the Reynolds number range 600⩽Re⩽1800. The computational domain has seven contiguous transverse grooves cut symmetrically into opposite walls, followed by a flat section with the same length. Periodic inflow/outflow boundary conditions are employed. The development and decay of unsteady flow is observed in the grooved and flat sections, respectively. The axial variation of the unsteady component of velocity is compared to the local heat transfer, shear stress and pressure gradient. The results suggest that intermittently grooved passages may offer even higher heat transfer for a given pumping power than the levels observed in fully grooved passages.

Topology of three-dimensional steady cellular flow in a two-sided anti-parallel lid-driven cavity

2017 ◽  
Vol 826 ◽  
pp. 302-334 ◽  
Author(s):  
Francesco Romanò ◽  
Stefan Albensoeder ◽  
Hendrik C. Kuhlmann
Keyword(s):  
Reynolds Number ◽  
Limit Cycle ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Convection Cell ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Driven Cavity ◽  
Dimensional Flow ◽  
Wide Range

The structure of the incompressible steady three-dimensional flow in a two-sided anti-symmetrically lid-driven cavity is investigated for an aspect ratio $\unicode[STIX]{x1D6E4}=1.7$ and spanwise-periodic boundary conditions. Flow fields are computed by solving the Navier–Stokes equations with a fully spectral method on $128^{3}$ grid points utilizing second-order asymptotic solutions near the singular corners. The supercritical flow arises in the form of steady rectangular convection cells within which the flow is point symmetric with respect to the cell centre. Global streamline chaos occupying the whole domain is found immediately above the threshold to three-dimensional flow. Beyond a certain Reynolds number the chaotic sea recedes from the interior, giving way to regular islands. The regular Kolmogorov–Arnold–Moser tori grow with increasing Reynolds number before they shrink again to eventually vanish completely. The global chaos at onset is traced back to the existence of one hyperbolic and two elliptic periodic lines in the basic flow. The singular points of the three-dimensional flow which emerge from the periodic lines quickly change such that, for a wide range of supercritical Reynolds number, each periodic convection cell houses a double spiralling-in saddle focus in its centre, a spiralling-out saddle focus on each of the two cell boundaries and two types of saddle limit cycle on the walls. A representative analysis for $\mathit{Re}=500$ shows chaotic streamlines to be due to chaotic tangling of the two-dimensional stable manifold of the central spiralling-in saddle focus and the two-dimensional unstable manifold of the central wall limit cycle. Embedded Kolmogorov–Arnold–Moser tori and the associated closed streamlines are computed for several supercritical Reynolds numbers owing to their importance for particle transport.

Three-dimensional flow in cavities

1963 ◽  
Vol 16 (4) ◽  
pp. 620-632 ◽  
Author(s):  
D. J. Maull ◽  
L. F. East
Keyword(s):  
Static Pressure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Large Span ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Oil Flow ◽  
Two Dimensional Flow

The flow inside rectangular and other cavities in a wall has been investigated at low subsonic velocities using oil flow and surface static-pressure distributions. Evidence has been found of regular three-dimensional flows in cavities with large span-to-chord ratios which would normally be considered to have two-dimensional flow near their centre-lines. The dependence of the steadiness of the flow upon the cavity's span as well as its chord and depth has also been observed.

Sign in / Sign up

Export Citation Format

Share Document