Abstract: The horizontal decanter centrifuge is widely used in the process of sludge dewatering, the dewatering efficiency of which is significantly influenced by structural and operating parameters, as well as material properties. Sludge modification is very important for sludge dewatering, and it has a greatly influence on sludge dewatering characteristics. The basic theory and the structural features of centrifuge and sludge modification technology are studied for the separating efficiency. The three-dimensional flow field in the centrifuge of structural parameters and spiral, and sludge modification on the dewatering efficiency are investigated numerically by using computational fluid dynamics(CFD) software FLUENT. The results show that improvement of separation efficiency can be achieved by not only increasing the length-diameter ratio, but also decreasing the sludge viscosity. In addition, the centrifuge with spiral or not with spiral has large impact on the simulation result, which should be noticed in the investigation.

Key words: centrifuge;numerical simulation;sludge;modification