Improving the calculation of collecting perforated pipelines for water treatment structures

et al. 2021

EEJET

Self Cite

Most production technologies require a uniform flow path of liquid from pressure distribution pipelines. To achieve this goal, it is proposed to introduce polymer additives into the liquid flow or to use converging distribution pipelines with a continuous longitudinal slot in the wall. To reduce the uneven operation of the distribution pipeline during discrete liquid dispensing, it is proposed to use cylindrical output rotary nozzles with a lateral orthogonal entry of the jet into the nozzle. The problem is the lack of methods for accurate hydraulic calculation of the operation of distribution pipelines. Adequate calculation methods are based on differential equations. Finding the exact solution of the differential equation of fluid motion with variable path flow rate for perforated distribution pipelines is urgent, because it still does not exist. The available calculation methods take into account only the right angles of separation of the jets from the flow in the distribution pipeline. These methods are based on the assumption that the coefficient of hydraulic friction and the coefficient of resistance of the outlets are constant along the flow. A calculation method is proposed that takes into account the change in the values of these resistance coefficients along the distribution pipeline. The kinematic and physical characteristics of the flow outside the distribution pipeline are also taken into account. The accuracy of calculating the value of the flow rate of water distributed from the distribution pipeline has been experimentally verified. The error in calculating the water consumption by the method assuming that the values of the resistance coefficients are unchanged along the distribution pipeline reaches 18.75 %. According to the proposed calculation method, this error does not exceed 6.25 %. However, both methods are suitable for the design of pressure distribution pipelines, provided that the jet separation angles are straight. Taking into account the change from 90° to 360° of the angle of separation of the jets from the flow in the distribution pipeline will expand the scope and accuracy of calculation methods.

Section: Discussion Of the Results Of The Analysis Of Methods For Calculating Pressure Distribution Pipelinesmentioning

confidence: 99%

The problem of hydraulic calculation of pressure distribution pipelines

Cherniuk

Hnativ

et al. 2021

EEJET

Self Cite

“…The scheme of the experimental installation and a detailed description of the experimental and measuring equipment, as well as the procedures of measurement and processing of the results obtained, are given in [19].…”

Section: The Study Materials and Methodsmentioning

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

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

“…The filtration resistance of the "soil-drain" system Ф and the hydraulic friction factor λ col are assumed to be constant along the pipeline and equal to their average value along the length. The angle, at which the liquid is connected to the main flow in the pipeline, is also constant and equal 2 /  [10]. Leakage of liquid from the drainage pipe can be carried out both in the atmosphere ( 0…”

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.