scholarly journals The problem of hydraulic calculation of pressure distribution pipelines

2021 ◽  
Vol 6 (7 (114)) ◽  
Author(s):  
Volodymyr Cherniuk ◽  
Roman Hnativ ◽  
Oleksandr Kravchuk ◽  
Vadym Orel ◽  
Iryna Bihun ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Flow Rate ◽  
Calculation Method ◽  
Fluid Motion ◽  
Hydraulic Calculation ◽  
Calculation Methods ◽  
Production Technologies ◽  
The Right ◽  
Longitudinal Slot ◽  
Resistance Coefficients

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.

Discussion of Hydraulic Calculation Methods for Hot Water Heating Direct Return System

2013 ◽  
Vol 353-356 ◽  
pp. 3049-3053
Author(s):  
Yong Zheng Fu ◽  
Yao Xiong ◽  
Hui Hui Liu
Keyword(s):  
Engineering Design ◽  
Constant Temperature ◽  
Calculation Method ◽  
Temperature Drop ◽  
Hot Water ◽  
Hydraulic Calculation ◽  
Calculation Methods ◽  
Water Heating ◽  
The Common ◽  
Hydraulic Balance

For hot water heating direct return system, the common hydraulic calculation method in engineering design is constant temperature drop method,which is calculated from the farthest riser loop. Due to the limit of the minimum pipe size, the method is usually difficult to achieve the hydraulic balance for every riser loop, and it needs the utilization of valves to meet the need. In this paper, through a calculation example, it has explained that every riser loop is very easy to achieve hydraulic balance without the utilization of valves when the system is calculated from the nearest riser loop. Besides, the calculation order of this method has been given.

scholarly journals PARTICULARITIES OF HYDRAULIC CALCULATION OF COLLECTING PREASSURE DRAINAGE PIPELINES

2021 ◽  
pp. 130-138
Author(s):  
O.A. Kravchuk ◽  
Keyword(s):  
Flow Rate ◽  
Fluid Motion ◽  
Hydraulic Calculation ◽  
Rate Variation ◽  
Dimensionless Form ◽  
Maximum Throughput ◽  
Limited Length ◽  
Filtration Capacity ◽  
Surrounding Soil

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.

Hydraulic model of a water cooling system in a chemical plant

1988 ◽  
Vol 53 (4) ◽  
pp. 788-806
Author(s):  
Miloslav Hošťálek ◽  
Jiří Výborný ◽  
František Madron
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Water ◽  
Graph Algorithm ◽  
Automatic Generation ◽  
Hydraulic Calculation ◽  
Return Flow ◽  
Flow Rates ◽  
Pressure Losses ◽  
Controlled Flow

Steady state hydraulic calculation has been described of an extensive pipeline network based on a new graph algorithm for setting up and decomposition of balance equations of the model. The parameters of the model are characteristics of individual sections of the network (pumps, pipes, and heat exchangers with armatures). In case of sections with controlled flow rate (variable characteristic), or sections with measured flow rate, the flow rates are direct inputs. The interactions of the network with the surroundings are accounted for by appropriate sources and sinks of individual nodes. The result of the calculation is the knowledge of all flow rates and pressure losses in the network. Automatic generation of the model equations utilizes an efficient (vector) fixing of the network topology and predominantly logical, not numerical operations based on the graph theory. The calculation proper utilizes a modification of the model by the method of linearization of characteristics, while the properties of the modified set of equations permit further decrease of the requirements on the computer. The described approach is suitable for the solution of practical problems even on lower category personal computers. The calculations are illustrated on an example of a simple network with uncontrolled and controlled flow rates of cooling water while one of the sections of the network is also a gravitational return flow of the cooling water.

scholarly journals A stable method for 4D CT-based CFD simulation in the right ventricle of a TGA patient

2020 ◽  
Vol 35 (5) ◽  
pp. 315-324
Author(s):  
Yuri Vassilevski ◽  
Alexander Danilov ◽  
Alexander Lozovskiy ◽  
Maxim Olshanskii ◽  
Victoria Salamatova ◽  
...  
Keyword(s):  
Right Ventricle ◽  
Cfd Simulation ◽  
Fluid Motion ◽  
4D Ct ◽  
Post Surgery ◽  
Surgery Patient ◽  
Time Dependent Domain ◽  
Flow Domain ◽  
The Right ◽  
Dependent Domain

AbstractThe paper discusses a stabilization of a finite element method for the equations of fluid motion in a time-dependent domain. After experimental convergence analysis, the method is applied to simulate a blood flow in the right ventricle of a post-surgery patient with the transposition of the great arteries disorder. The flow domain is reconstructed from a sequence of 4D CT images. The corresponding segmentation and triangulation algorithms are also addressed in brief.

Hydraulic Calculation Method Study of Branch Shape Water-Injection Pipe Network Based on Binary Tree

2011 ◽  
Vol 317-319 ◽  
pp. 2266-2270
Author(s):  
Li Xin Wei ◽  
Jiang Bo Wen ◽  
Lu Ying Zhang ◽  
Yan Chun Xu ◽  
Peng Li
Keyword(s):  
Computer Program ◽  
Calculation Method ◽  
Binary Tree ◽  
Water Injection ◽  
Hydraulic Calculation ◽  
Pipe Network ◽  
Structure Characteristics

On the basis of analyzing process and structure characteristics of branch shape water-injection pipe network, this paper established a hydraulic calculation method of branch shape water-injection pipe network based on binary tree. This method has many advantages, such as calculation speed is fast, occupying less memory, having high calculation accuracy, and so on. According to it, this paper compiled a computer program and presented an actual example.

Mathematical model of pressure distribution in a main pipeline during pumping with the use of drug reducing agents, taking into account their degradation

2021 ◽  
pp. 396-406
Author(s):  
Мурсалим Мухутдинович Гареев ◽  
Марат Иозифович Валиев ◽  
Филипп А. Карпов
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Pressure Distribution ◽  
Flow Rate ◽  
Pressure Head ◽  
Petroleum Products ◽  
Reducing Agents ◽  
Main Pipeline ◽  
Main Mode ◽  
Pipeline Pressure

Путевая деградация противотурбулентных присадок (ПТП) может стать причиной изменения основных параметров режима магистрального трубопровода - давления и расхода - относительно установившихся значений и осложнить контроль их отклонений от нормативных показателей. При этом до настоящего момента отсутствовала методика расчета режимов перекачки при использовании ПТП с учетом деградации. Авторами была поставлена цель по разработке методики для математического описания распределения давления в трубопроводе с учетом путевой деградации присадки, а также при различных концентрациях ПТП. Для достижения указанной цели предлагается дополнить уравнение баланса напоров с учетом эмпирической зависимости эффективности присадки от длины трубопровода. При расчетах давления в промежуточных точках трассы предлагается использовать данные опытно-промышленных испытаний по изменению эффективности ПТП. Для иллюстрации применения методики рассматриваются примеры перекачки нефти и нефтепродуктов с добавлением присадок в различных концентрациях. На основании экспериментальных данных получена адекватная математическая модель снижения эффективности ПТП по длине магистрального трубопровода для различных концентраций вводимой присадки. Path degradation of drug reducing agents (DRA) can cause changes in the main mode parameters of the main pipeline; pressure and flow rate, relative to the stable values, and complicate the adjustment of their deviations from the standard indicators. At the same time, up until now there has been no methodology for calculating pumping modes when using DRA that takes degradation into account. The authors set a goal to develop a methodology to mathematically describe the pressure distribution in the pipeline, taking into account the path degradation of the agent, as well as the parameters at different DRA concentrations. To achieve this goal, it is proposed to supplement the equation of the pressure head balance with the empirical dependency of agent efficiency on the length of the pipeline. When calculating the pressure at intermediate points of the route, it is proposed to use the pilot run data on the change in the DRA efficiency. To illustrate the application of the methodology, examples of pumping oil and petroleum products with added agents in various concentrations are discussed. On the basis of the experimental data, an adequate mathematical model of the DRA efficiency reduction along the length of the main pipeline for different concentrations of introduced agent was obtained.

Crack width calculation methods for large-scale concrete structures for the Ferry-Free E39

2018 ◽  
Author(s):  
Reignard Tan ◽  
Terje Kanstad ◽  
Mette R. Geiker ◽  
Max A. N. Hendriks
Keyword(s):  
Cross Sections ◽  
Calculation Method ◽  
Crack Width ◽  
Large Scale ◽  
Concrete Structures ◽  
Calculation Methods ◽  
Empirical Formulas ◽  
Eurocode 2 ◽  
Semi Empirical

<p>Motivated by the establishment of a Ferry-Free E39 coastal highway route, crack width calculation methods for design of large-scale concrete structures are discussed. It is argued that the current semi-empirical formulas recommended by Eurocode 2 is inconsistent and overly conservative for cross sections with large bar diameters and covers. A suggestion to formulating a more consistent crack width calculation method is given.</p>

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