Thesis (M.Eng.)--Chulalongkorn University, 1997

The phenomena of air flow past the parallel inclined flat plates in a square duct is studied through the numerical solution by using computational fluid dynamics (CFD) technique. A computer program called PHOENICS, is adopted to solve for three-dimensional steady turbulent flow under the finite volume method. The governing equations are incompressible ensemble-averaged Navier-Stokes equations. The Reynolds stresses are modeled by the k-E turbulence model with Boussinesq's eddy viscosity assumption. To verify the numerical accuracy and validity of the turbulence model, the results are first compared with experimental velocity data. Comparisons between measured and calculated results are in general satisfactory, although some discrepancies are found. Finally, the effects of the number of flat plates, the inclination of flat plates and high Reynolds number in the duct flow, to the distance for fully developed flow, as well as total pressure drop, are investigated. The predictions show that the development length extends when the number of flat plates decreases, however, such length is shortened when the inclination of flat plates becomes smaller. In case of Reynolds number within the range of study, the numerical results predict that the air flow at higher Raynolds number requires the development length to be longer than the lower Reynolds number condition. Furthermore, it is found that the single blade damper causes total pressure drop to be significantly higher than the multi-blade damper.