Computations of Turbulent Flow Characteristics and Heat Transfer on Forward-Facing Steps.

Document Type : Research Studies

Authors

1 Mechanical Engineering Department., Faculty of Technological Studies., Kuwait

2 Mechanical Engineering Department., College of Engineering & Petroleum Kuwait University., Kuwait

Abstract

 Numerical calculations of heat transfer and flow field characteristics of turbulent recirculating flows on forward-facing steps are presented in this paper. The calculations are based on the (k - ɛ) model. In the vicinity of the wall a linear vorticity distribution model was used. The (k - ɛ) model has improved to account for the streamline curvature and the Reynolds stresses, and the computer program was also improved with a finite difference and iterative technique. 
The present results include computed heat transfer coefficients, streamlines and isothermal lines, velocity profiles and kinetic energy distributions at different Reynolds numbers and different step heights. 
One of the significant results in this study is the influence of the step height on the size and location of the separation region and reattachment point. It was found that the heat transfer mechanism is positively influced by larger step sizes. The size of the isothermal lines becomes smaller and closer to the wall by larger steps. This result is noticed both upstream and downstream of the step. 
 

 
 

Main Subjects