Optimization of a Closed 2-Channel Impeller With Experimental and Optical Support

Due to the high number of solids in wastewater and the resulting increased susceptibility to clogging for wastewater pumps, wastewater impellers are classically designed with a low number of blades as semi-open or closed impellers. In addition to higher possible efficiencies, the closed impellers also have an advantage in terms of resistance to wear compared to semi-open impellers. However, the closed 2-channel impellers have not yet been able to demonstrate good resistance to clogging by fibrous materials. Based on an already tested impeller (MOD 0), two further modifications are discussed in this publication, which show significant improvements in clogging behavior with the help of a optimization methodology. These are mainly achieved in the first modification (MOD 1) by a strongly thickened blade geometry, which can already achieve an initial improvement in clogging susceptibility. The second modification (MOD 2) takes up this thickened blade, whereby the concave suction side of the blade is made convex. This also significantly improves the slipping behavior of the dusters, resulting in a closed 2-channel impeller with a low susceptibility to clogging.