Determination of the diameter variation peculiarities along the path of distribution drainage pipe-line

Abstract

This article presents a methodology for calculating the hydraulic characteristics and structural parameters of variable (decreasing) cross-sectional distribution pressure drainage pipelines. The approach is based on analyzing a system of differential equations describing fluid flow with a variable flow rate in the investigated pipes. The study explores the most general case of distributor operation, considering a horizontal groundwater level above the pipeline. The analysis of the original equations includes a scenario where a constant average fluid flow rate is maintained along the length of the pressure channel. The velocity magnitude is influenced by the granulometric features of the surrounding soil and the filtration characteristics of the pipeline's side walls material. The investigation employs the concept of a conditional distribution infinitely long pipeline or a pipeline with limited length and infinite permeability of the side walls surface. This allows assuming a pressure close to zero at the pipeline's final cross-section, which minimally impacts the obtained results. The analysis is presented in a dimensionless form, and the resulting computational formulas are both simple and convenient. The article includes corresponding graphs to illustrate the presented dependencies.