关键词: 浮渣分离, 卧螺离心机, 数值模拟, 分离性能

Abstract: Traditional decanter centrifuge is only used to separate heavy sludge rather than floating sludge. This research developed a two-phase numerical simulation on a decanter centrifuge in separating light solid floating sludge. The three dimension software Pro-E was used to build the 3D model. The computational fluid dynamics software Fluent was applied to analyze volume fraction distribution of the solid and liquid phase as well as the effects of operating conditions and fluid parameters on flow field and separation properties. The simulation was based on Euler multiple phase flow model and RNG k-ε turbulence model in a multiple coordinate reference system. The simulation results showed that the decanter centrifuge can be used to separate high density and middle-coarse particles;the fluid settling lamination was obvious and water was in the inner side while floating sludge outside of cistern;there was little effect of rotation speed discrepancy on separation properties. Rotation speed discrepancy in the range of 30-70r/min was optimal. With the increase of the feed concentration,particles'setting velocity and separation efficiency decreased. Low setting velocity for small particles resulted in less separation efficiency and coarse particles had higher separation capabilities because of quick setting velocity.

Key words: light floating sludge separation, decanter centrifuge, numerical simulation, separation properties