NUMERICAL STUDY OF TURBULENT-FLOW IN 2-DIMENSIONAL CHANNEL WITH SURFACE MOUNTED OBSTACLE

This paper presents the numerical predictions of the fluid and heal tr ansfer characteristics for the turbulent channel flow with one and two obstacles. The turbulent governing equations are solved by a control- volume-based finite-difference method with nan-uniform staggered grids and the well-known k-epsilon model and its associated wall function t o describe the turbulence structure. The velocity and pressure terms o f momentum equations are solved by the SIMPLE method. The parameters i nterested include entrance Reynolds number (between 10(4) and 10(6)), the ratio of channel height to obstacle height (B/H) and the dimension less distance between two obstacles (PR). Computations are carried out for three working mediums, air, water and Freon R-12. The predicted a ttachment point located at x/H = 12.24 are compared with the experimen tal results of x/H = 12.3 for the unheated single Obstacle case with B /H = 15. The predicted heat transfer around the attachment point is mu ch better than that in the recirculation region due to the strong impa ct at the attachment point.