| Summary: | 碩士 === 國立中興大學 === 機械工程學系 === 89 === In this study , a computational fluid (CFD) code , PHOENICS is used to calculate the three-dimensional nature of turbulent flow in a channel with porous baffles. Owing to the turbulent characteristic by the porous baffles flowfield, the continuity equation , momentum equation , and the k-ε turbulence model are adopted to construct the model with control volume integration for finite difference associated with SIMPLE-C algorithm .The porous baffles are arranged on the bottom and top channel walls in a staggered manner. And we will investigate the various parameters , such as Reynolds number(Re= 10000 to 50000) and the porosity of the baffle (0%,20% and 42%), respectively; the baffle broad ratio (w/W=1/4,1/2,3/4 and 1) and the baffle height ratio (h/H=0.25,0.5 and 0.75). The correlation for the average Nusselt number and friction factor are also developed in terms of flow and baffled parameters .
From the present result result , the average Nusselt number of a 3-D duct in the porous baffle is higher about 63~73% than the solid baffle when the baffle height and Reynolds number of flow field are fixed. And the friction factor of solid baffle is higher about 65~81% than the porous baffle. Consequently, the results of the investigation will provide a reference and fundamental optimize design for the porous baffle in the heat exchanger.
|
|---|
