0
TECHNICAL PAPERS: Heat Transfer Enhancement

Heat Transfer Enhancement by Delta-Wing-Generated Tip Vortices in Flat-Plate and Developing Channel Flows

[+] Author and Article Information
M. C. Gentry, A. M. Jacobi

Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801

J. Heat Transfer 124(6), 1158-1168 (Dec 03, 2002) (11 pages) doi:10.1115/1.1513578 History: Received August 24, 2001; Revised June 26, 2002; Online December 03, 2002
Copyright © 2002 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Flow manipulators used as vortex generators to enhance heat transfer, along with the relevant geometrical definitions (adapted from Ref. 2)
Grahic Jump Location
Wind tunnel, with the following components: (A) inlet, (B) honeycomb and screens, (C) contraction, (D) test section, (E) instrumentation access, (F) transition, (G) blower, (H) acoustic plenum, (I) flow measurement section, and (J) discharge to outside laboratory
Grahic Jump Location
This vane-type vortex meter was constructed using a small steel shaft, wire, a hypodermic needle, and small pieces of foil, sized to fit within the Thomson–Rankine vortex core
Grahic Jump Location
A schematic showing tip vortices and their images, with induced velocities denoted as Vij for the velocity of vortex i induced by vortex j: (a) vortices over a flat plate, and (b) vortices in a channel flow, where only the first-order image vortices are shown (images of images are neglected)
Grahic Jump Location
Two views of an image recorded using dye-in-water visualization, showing instability in vortices generated by a delta-wing VG at the leading edge of a flat plate, with Λ=1.25, α=35 deg, and Rec=1300. The λw periodicity corresponds roughly to that predicted using the buckling instability theory of Bejan 21.
Grahic Jump Location
Measured vortex circulation as a function of position downstream from the leading edge of a flat plate, over a range of (a) VG aspect ratio, (b) Rec, and (c) VG attack angle. Closed symbols were obtained with the vane-type vortex meter, and open symbols were obtained from the flow visualization data.
Grahic Jump Location
Sherwood number enhancement for a flat-plate flow as a function of VG aspect ratio and attack angle at (a) Rec=300, (b) Rec=800, (c) Rec=1300
Grahic Jump Location
Spatially averaged enhancement ratio for the flat-plate flow as a function Reynolds number based on integration length, with Λ=1.25, α=35 deg, and for Rec=1300
Grahic Jump Location
Local Sherwood number distribution for a delta wing attached to a flat plate, with Λ=1.25, α=35 deg, and (a) Rec=800, (b) Rec=1300. Note that in regions of surface-normal inflow associated with the vortex pair an enhancement is realized, and in surface-normal outflow regions the boundary-layer thickens and a reduction in the convection coefficient is manifest. Note also that different scales are used for the two plots.
Grahic Jump Location
Two views of an image recorded using dye-in-water visualization, showing vortices generated by a delta-wing VG at the leading edge of the channel, with Λ=1.25, α=35 deg, and Redh=1200
Grahic Jump Location
Dimensionless vortex circulation as a function of Redh for a delta wing in a channel flow with Λ=1.25 and α=15 deg, 35 deg, and 55 deg. Solid symbols were obtained using the vortex meter, and open symbols were obtained with the potential flow model. Ratio c/dh=0.95.
Grahic Jump Location
Sherwood number enhancement for a channel flow as a function of VG aspect ratio and attack angle at (a) Redh=400, (b) Redh=1200, (c) Redh=2000. The data are averaged over both sides of the complete channel.
Grahic Jump Location
Spatially averaged enhancement ratio for the channel flow as a function inverse Graetz number based on integration length, with Λ=1.25, α=35 deg, and Redh=2000. Data are presented for both surfaces of the channel and the channel as a whole.
Grahic Jump Location
Local Sherwood number distribution for a delta wing in a developing channel flow, with Λ=1.25, α=35 deg (c/dh=0.95,L/c=11.43): (a) Redh=400, (b) Redh=1200, and (c) Redh=2000.
Grahic Jump Location
Pressure-drop penalty for VG enhanced channel flow, over a range of aspect ratio, attack angle and Reynolds number: (a) Λ=0.5; (b) Λ=1.25; and (c) Λ=2.0 (c/dh=0.95,L/c=11.43).

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In