Study on clogging mechanism of fibrous materials in a pump by experimental and computational approaches

Clogging trouble in a sewage pump is a serious problem caused by foreign substances like strings, towels, and cloths. However, mechanism of pump clogging is significantly complicated and it is difficult to clarify factors affecting pump clogging. In this paper, the simplified air duct test and axial fan test are introduced and some parameter studies based on design of experiments (DOE) were conducted. From the DOE results, the sensitivity of each parameter to the clogging was predicted. As the parameters related to the clogging, length and rigidity of the strings, leading shape and lean angle of obstacles, flow velocity in a measuring section were selected. Behavior of string in the pump was also observed in the actual pump apparatus and was compared to that in the air duct. Computational simulation with simplified flow fields and MBD (Multi Body Dynamics) was developed and applied to predict behavior of a string in the pump. These experiments and computation are effective to detect and classify the clogging mechanism. These approaches aided to establish one of the evaluation methods on anti-clogging performance against fibrous materials.