Method of hydraulic calculation of partially silted slurry piping

Анотація

A critical mode of transportation of solid dispersed materials by a stream of water in a partially muddy horizontal pipeline is considered. Typical of this mode of hydraulic transport is that the silt layer prevents the pipeline from rapid wear and that with increasing layer height, the critical flow velocity below which solid material precipitates into the sediment decreases, while the hydraulic friction resistance increases sharply. One of the important tasks of the study of the critical mode of motion of the slurry with partial siltation is to develop scientifically sound methods of calculating the critical flow velocity and specific losses of the friction head. In the work a generalized technique of hydraulic calculation of partially silted and, in particular, non-silted pipelines is developed which is based on a system of two algebraic equations describing the critical mode of operation of a pipeline. One equation is used to determine the specific friction head losses, and the other to determine the critical velocity corresponding to the specific head losses. A partial case is also considered when the experimental or calculated values of critical velocity and specific head losses are known for the unmodified pipe, but must be recalculated for the partially unmodified pipe. For this case, simple calculation formulas are proposed for the operational prediction of the named parameters in the case of partial siltation. Examples of calculation are given.