Calculation of the hydraulic characteristics of the protective coating used in trenchless technologies for the construction and renovation of pipelines to extend their service life

Abstract

Abstract. The lifetime of the pipeline, which undergoes trenchless repair by pulling and then fixing various types of internal protective coatings inside, is determined by the strength characteristics of the two-layer structure "old pipeline + internal protective coating". Hydraulic parameters of internal protective coatings, such as surface roughness and degree of hydrophobicity (water repellency), can play a role in prolonging the life of the repaired pipeline. With a high degree of hydrophobicity of the protective coating, the contact of the transported liquid with the walls of the pipeline during its operation in the non-pressure regime decreases, which leads to a decrease in the negative impact on the walls, in particular, their attrition, interaction with the specific structure of the coating material, which in turn reduces the energy costs when transporting water. Given article deals with a mathematical description of the interaction of the surface structure (with its inherent wetting ability) and the transported liquid in a mini-stream created on an inclined open chute imitating the inner surface of a pressureless pipeline. The theoretical positions and methodology for calculating the degree of hydrophobicity are based on research conducted on the basis of frontal and coaxial (along the flow) digital photo and video. T

Restoration of dilapidated pipeline networks using polymer hoses

“…A dilapidated cast-iron pipeline with an internal diameter of 0.4 m and a length of 400 m, lying at a depth of 3.0 m, is considered as an object of restoration. Based on preliminary calculations for two alternatives, the following values were obtained: for the elastic modulus of the sleeve E (3500 N/mm 2 ) based on fiberglass and its bending strength δ (75 N/mm 2 ) to ensure the bearing capacity of the pipeline, the wall thickness of the sleeve should be 5.1 mm, and the inner diameter of the restored pipeline 0.4 -2•0.0051=0.3898 m; with the elastic modulus of the sleeve E (1400 N/mm 2 ) based on polymer fibers and its bending strength δ (18 N/mm 2 ), the wall thickness of the sleeve should be 7.3 mm, and the inner diameter of the restored pipeline 0.4 -2•0.0073 =0.3854 m [16].…”

Influence of the temperature factor on the hydraulic resistance of pressure pipes

“…The studied materials have been represented by polyethylene pipes, subject to necessary identification of the dynamics of the coefficient of hydraulic friction change in a wide range of temperatures both of the transported liquid and the pipeline environment (for example, indoors, during ground or underground pipe laying, etc.). The results of the hydraulic experiments were processed using automated software programs [15][16].…”

Rapid recovery of old steel piping capacity with energy saving effect by reducing hydraulic resistance values

“…Для определения степени деформации трубопроводов (изменения диаметра и толщины стенки полимерной трубы после операций ее термомеханического сжатия и распрямления), при использовании технологии Swagelining, применялась специальная автоматизированная программа [11].…”