Pipelines designing for steady water collection along the path

Cherniuk

et al. 2022

EEJET

The results of an experimental study of the hydraulic friction factor of perforated pipelines that work with the collection of fluid along the path are reported. Clarification of this issue will make it possible to solve an important engineering task – to devise a reliable procedure for the hydraulic calculation of perforated pipes. The experiments were carried out on an assembled experimental bench. A steel pipeline with a perforated part of 1–3 m was investigated. Perforation holes were taken with a diameter of 3.6 and 9 mm. In the experiments, fluid flow, pressure loss, and average velocity were measured. Based on the data obtained, the values of the coefficient under study were calculated. It has been established that it is significantly larger than its values with uniform movement and is variable in length of the pipeline. Experimental dependences λcol on the value of the ratio of the velocities of the flowing jets of liquid to the average flow velocity in the corresponding section (Uh/V), as well as on the design characteristics of the channel, were obtained. It is shown that the lower value of the degree of pipe perforation corresponds to the higher values of λcol. This result can be explained by the influence of the attached flow rate on the main flow. The confirmation of this conclusion is the resulting shapes of diagrams of the average flow velocity obtained in the experiments, which differ significantly from standard diagrams with uniform motion. Obviously, additional energy is spent on the reformation of the velocities, and this causes additional head losses. Dependences were obtained for calculating the considered coefficient for prefabricated pipelines, including in the presence of transit flow rate. Their use in the calculation of the pipes under consideration will increase the reliability and efficiency of the sewage treatment plant, in which they are important structural elements

Section: Experimental Dependences For Calculating the Coefficient β Colmentioning

confidence: 99%

Assessing the value of the hydraulic friction factor in pipelines working with a flow connection along the path

Cherniuk

et al. 2022

EEJET

“…is variable head drop along the length, under which action a liquid inflow from the environment into the pipeline is taking place;  , , , D V Q are, respectively, the flow rate, average velocity, diameter, and free cross-sectional area of the flow at the distance x from the beginning of the pipe; Ф is dimensionless drain filtration resistance (its definition is a separate filtration problem [2]); k is soil hydraulic conductivity around the pipe; λ col is hydraulic friction factor of collecting drainage pipeline [9]; g is gravitational acceleration.…”

Section: Fig 1 Scheme Of the Pressure Collecting Drainage Pipeline Operationmentioning

confidence: 99%

Particularities of Hydraulic Calculation of Collecting Preassure Drainage Pipelines

Kravchuk¹

2021

BOSACEA

A system of two differential equations, which describes the fluid motion in a pipe with a variable flow rate and the conditions for fluid entry through the drainage pipelines walls from the surrounding soil, is considered. It is shown that for the studied case the second term in the original equation can be neglected without a significant error. The system is reduced to a dimensionless form by introducing the original variables. The solution of this equations system is given in a dimensionless form. Two main parameters are used in the analysis: the coefficient of collecting drainage pipeline resistance "ζl" and the generalized parameter "A", which takes into account the structural and hydraulic characteristics of the considered flow. Also, the concept of an infinitely long drainage pipeline or, which is the same, a pipeline with an infinite walls filtration capacity of the drainage pipeline is introduced in the article. It is noted that such pipeline will have a maximum throughput compared to pipes of the same diameter but limited length. Sufficiently simple and convenient calculated dependencies for the determination of the nature of flow rate variation and pressure drop along the length of the pipeline were obtained on the basis of the conducted analysis. Series of calculations of important characteristics for such pipes were carried out on the basis of offered formulas. Corresponding graphical dependencies were built for visibility. In particular, graphs of the flow rate variations at the end of the collector, depending on the design and filtration characteristics of the “soil-drain” system, are presented. Graph, that shows the dependence of the change in the flow rate connection unevenness along the length of the drainage pipeline at various hydraulic conductivity values of the surrounding soil, is important for understanding the drainage pipes particularity. The necessity to take into account the nature of the flow rate connection unevenness along the length for obtaining reliable results when calculating real drainage pipelines is shown in the article.

“…Як показує практика, методика гідравлічного розрахунку даних трубопроводів суттєво відрізняється від методів розрахунку характеристик трубопроводів з суцільними стінками, що транспортують рідину з постійною витратою. Головною особливістю розрахунку труб даному випадку є наявність змінної витрати вздовж шляху [4]. При цьому базовим рівнянням для аналізу слугує залежність гідравліки змінної маси у вигляді, запропонованому Г.Г.…”

Section: результати та поясненняunclassified

Determination of Boussinesq and Coriolis coefficients for pipelines operating with discharge connection along the path

Kravchuk¹,

Kochetov²,

Kravchuk³

2021

PWSH

Self Cite

Peculiarities of the diagrams of averaged fluid velocities in the cross-sections of pressure collecting perforated pipelines were determined on the basis of the experimental studies conducted by the authors. The most characteristic typical diagrams of averaged velocities in the pipelines cross-sections with their different design characteristics were given. A comparative analysis of the obtained diagrams with the diagrams of velocities that occur during uniform motion in pressure pipelines with solid walls was carried out. It is shown that the main difference between them occurs in the flow zones, which are located near the pipeline walls. It was explained by the connected liquid jets effect on the main flow. The degree of diagrams deformation was estimated by the value of the momentum coefficient α0 (Boussinesq coefficient) and the coefficient of kinetic energy α (Coriolis coefficient). It was determined that in the general case these coefficients will be variable in magnitude along the length of the studied pipes. Nevertheless, these coefficients are recommended to be constant in magnitude in engineering calculations. The limits of the structural characteristics of collecting perforated pipes for which this non-uniformity of the diagrams must be taken into account, and for which it can be neglected were determined on the basis of the analysis of the equation of fluid motion with a variable flow rate.