0
Research Papers: Heat Transfer Enhancement

Numerical Prediction of Turbulent Flow and Heat Transfer Enhancement in a Square Passage With Various Truncated Ribs on One Wall

[+] Author and Article Information
Gongnan Xie

e-mail: xgn@nwpu.edu.cn

Weihong Zhang

Engineering Simulation and Aerospace
Computing (ESAC),
Northwestern Polytechnical University,
P.O. Box 552,
Xi'an, Shaanxi 710072, China

Giulio Lorenzini

Department of Industrial Engineering,
University of Parma,
Parco Area delle Scienze, 181/A,
Parma 43124, Italy
e-mail: giulio.lorenzini@unipr.it

Cesare Biserni

Department of Industrial Engineering,
University of Bologna,
Viale Risorgimento 2,
Bologna 40136, Italy

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the Journal of Heat Transfer. Manuscript received November 16, 2012; final manuscript received July 2, 2013; published online October 25, 2013. Editor: Terrence W. Simon.

J. Heat Transfer 136(1), 011902 (Oct 25, 2013) (11 pages) Paper No: HT-12-1612; doi: 10.1115/1.4024989 History: Received November 16, 2012; Revised July 02, 2013

Repeated ribs are often employed in the midsection of internal cooling passages of turbine blades to augment the heat transfer by air flowing through the internal ribbed passages. Though the research of flow structure and augmented heat transfer inside various ribbed passages has been well conducted, previous works mostly paid much attention to the influence of rib topology (height-to-pitch, blockage ratio, skew angle, rib shape). The possible problem involved in the usage of ribs (especially with larger blockage ratios) is pressure loss penalty. Thus, in this case, the design of truncated ribs whose length is less than the passage width might fit the specific cooling requirements when pressure loss is critically considered. A numerical study of truncated ribs on turbulent flow and heat transfer inside a passage of a gas turbine blade is performed when the inlet Reynolds number ranges from 8000 to 24,000. Different truncation ratio (truncated-length to passage-width) rib geometries are designed and then the effect of truncation ratio on the pressure drop and heat transfer enhancement is observed under the condition of constant total length. The overall performance characteristics of various truncated rib passages are also compared. It is found that the heated face with a rib that is truncated 12% in length in the center (case A) has the highest heat transfer coefficient, while the heated face with a rib that is truncated 4% at three locations over its length, in the center and two sides (case D), has a reduced pressure loss compared with passages of other designs and provides the lowest friction factors. Although case A shows larger heat transfer augmentation, case D can be promisingly used to augment side-wall heat transfer when the pressure loss is considered and the Reynolds number is relatively large.

Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

The simplified rectangular duct with ribs (unit: mm)

Grahic Jump Location
Fig. 2

Four different truncated rib configurations

Grahic Jump Location
Fig. 3

Nusselt number distribution along centerline at Re = 8000

Grahic Jump Location
Fig. 4

The Surface structured grid of ribbed duct (case A)

Grahic Jump Location
Fig. 5

Nusselt number distribution for different grid systems, case A, Re = 8,000

Grahic Jump Location
Fig. 6

Flow streamlines, TKE in streamwise-spanwise plane located at z = 2 mm at Re = 8000 for all cases. (a) Flow streamlines and (b) TKE.

Grahic Jump Location
Fig. 7

Normalized distributions of streamwise velocity component and streamwise vorticity of case A at different spanwise cross sections

Grahic Jump Location
Fig. 8

Temperature contours on the heating bottom-wall and side-walls of all cases (K)

Grahic Jump Location
Fig. 9

Normalized Nusselt number and friction factor

Grahic Jump Location
Fig. 10

Local Nusselt number contours in streamwise-spanwise plane located at bottom wall at Re = 8000 for all cases

Grahic Jump Location
Fig. 11

Centerline streamwise normalized Nusselt number at Re = 8000 of all cases

Grahic Jump Location
Fig. 12

Centerline streamwise normalized Nusselt number at different Reynolds numbers of case A

Grahic Jump Location
Fig. 13

Streamwise normalized Nusselt number at different y/H at Re = 8000 of all cases

Grahic Jump Location
Fig. 14

Thermal performance of all passages with truncated ribs

Grahic Jump Location
Fig. 15

Heat transfer coefficient versus pumping power

Grahic Jump Location
Fig. 16

Nusselt number ratio normalized by active area ratio

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