Turbulent Separated Convection Flow Adjacent to Backward-Facing Step-Effects of Step Height

Authors

Yitung Chen, University of Nevada, Las VegasFollow
J. H. Nie, University of Nevada, Las VegasFollow
B. F. Armaly, University of Missouri - RollaFollow
Hsuan-Tsung Hsieh, University of Nevada, Las VegasFollow

Document Type

Article

Publication Date

9-2006

Publication Title

International Journal of Heat and Mass Transfer

Volume

49

Issue

19-20

First page number:

3670

Last page number:

3680

Abstract

Simulations of turbulent convection flow adjacent to a two-dimensional backward-facing step are presented to explore the effects of step height on turbulent separated flow and heat transfer. Reynolds number and duct’s height downstream from the step are kept constant at Re₀ = 28,000 and H = 0.19 m, respectively. Uniform and constant heat flux of q_w = 270 W/m² is specified at the stepped wall downstream from the step, while other walls are treated as adiabatic. The selection of the values for these parameters is motivated by the fact that measurements are available for this geometry and they can be used to validate the flow and heat transfer simulation code. Two-equation low-Reynolds-number model is employed to achieve the turbulent Prandtl number. The primary and secondary recirculation regions increase in size as the step height increases. The bulk temperature increases more rapidly as the step height increases. Increasing the step height causes the magnitude of the maximum turbulent kinetic energy to increase. Near the step and below the step height, the turbulent kinetic energy becomes smaller as the step height increases. Inside the recirculation region, magnitude of the peak friction coefficient does not significantly change with the increase of step height. The friction coefficient becomes smaller in magnitude with the increase of the step height. The peak Stanton number becomes smaller as the step height increases.

Keywords

Heat – Convection; Heat – Transmission; Turbulence

Disciplines

Fluid Dynamics | Mechanical Engineering

Language

English

Permissions

Use Find in Your Library, contact the author, or interlibrary loan to garner a copy of the item. Publisher policy does not allow archiving the final published version. If a post-print (author's peer-reviewed manuscript) is allowed and available, or publisher policy changes, the item will be deposited.

Repository Citation

Chen, Y., Nie, J. H., Armaly, B. F., Hsieh, H. (2006). Turbulent Separated Convection Flow Adjacent to Backward-Facing Step-Effects of Step Height. International Journal of Heat and Mass Transfer, 49(19-20), 3670-3680.