The local resistance of sewage flows as two-phase fluid is larger than that of water flows under the same conditions. The accrual is variable according to different concentration, properties and size composition of contamination.

• 污水两相流动时的局部阻力大于清水流动时，其增加值随着污染物浓度及污染物的性质和粒径组成的不同而有所变动。