scholarly journals Real Values of Local Resistance Coefficients during Water Flow through Welded Polypropylene T-Junctions

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 895
Author(s):  
Marek Kalenik ◽  
Marek Chalecki ◽  
Piotr Wichowski
Keyword(s):  
Water Flow ◽  
Resistance Coefficient ◽  
Water Supply Systems ◽  
Internal Diameter ◽  
Local Resistance ◽  
Water Flow Velocity ◽  
Local Resistance Coefficient ◽  
Flow Through ◽  
Supply Systems ◽  
Resistance Coefficients

The paper presents results of investigation of the local resistance coefficient ζ in welded polypropylene T-junctions with the internal diameter 13.2 mm. The investigations were performed on an independently constructed test rig. The scope of investigations encompassed the T-junctions, which were (1) properly warmed up and properly pressed, (2) poorly warmed up and poorly pressed, or (3) excessively warmed up and excessively pressed. The local resistance coefficients ζ determined by measurements according to the standard PN-EN 1267:2012(Designation of the Polish Standard) were compared to those determined with use of the nomograms recommended for designing water supply systems and installations. Real values of the coefficients ζ, obtained in measurements were significantly higher than those read from the nomograms. The local resistance coefficients ζ in welded polypropylene T-junctions depend on water flow velocity and the manufacturing precision of a T-junction joint.

scholarly journals Explanation of tuberculation scales formation in steel and iron pipes using the theory of wave motion of a liquid

2018 ◽  
Vol 178 ◽  
pp. 04002
Author(s):  
Alexey Andrianov ◽  
Evgeny Orlov
Keyword(s):  
Flow Velocity ◽  
Water Flow ◽  
Electrochemical Corrosion ◽  
Water Supply Systems ◽  
Water Flow Velocity ◽  
Corrosion Deposits ◽  
The Difference ◽  
Corrosion Of Steel ◽  
Supply Systems ◽  
Turbulent Water

Electrochemical corrosion of steel and iron pipes in water supply systems is a common problem that causes financial losses to operating companies and deteriorates water quality. A comprehensive study of corrosion deposits formation mechanism is necessary for a better understanding of the processes occurring in pipelines and for scientific justification of monitoring and predicting techniques. The influence of various factors (in particular the water flow velocity) on the formation, growth, and spatial distribution of tuberculation scales on the inner surface of pipes is considered. To study the effect of flow velocity, simple serial tests were carried out on segments of a steel non-galvanized pipe in static and dynamic conditions. The difference in the formation of anode and cathode sections in two dynamic modes is recognized. The first stage of tubercle formation is observed. It was assumed that in pipes with turbulent water flow near metal surface, waves forming tubercles are appeared, and the distribution of the tubercles is depend on water flow velocity.

scholarly journals Numerical Calculation of the Tee Local Resistance Coefficient

2015 ◽  
Vol 9 (1) ◽  
pp. 876-881 ◽  
Author(s):  
Qin Zhang ◽  
Manlai Zhang ◽  
Zhihong Zhou ◽  
Shizhong Wei
Keyword(s):  
Cfd Simulation ◽  
Flux Ratio ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Head Loss ◽  
Local Resistance ◽  
Local Resistance Coefficient ◽  
Tee Junction ◽  
Resistance Coefficients

The local head loss of tee could be calculated with the determination of local resistance coefficient by CFD simulation and test. Based on the mesh-independent feature identified, the flow field inner tee was numerically simulated by the standard k - ε turbulent model and SIMPLEC algorithms, which has revealed the mainstream was obliged to turn to the opposite side of tee junction, and a rise in pressure drop between upstream and downstream was caused as a result. Furthermore, the frictional resistance coefficient was calculated for eliminating the frictional head loss of model, which decreased from 0.0207 to 0.0133 when the inlet velocity increased from 1 m/s to 12 m/s. Additionally, the local resistance coefficients of tee at flow conditions were attained, and the quadratic polynomial between the local resistance coefficient and flux ratio was presented due to the influence of branch on mainstream. Through the test, the simulation result has been compared and the effectiveness of simulation has been verified.

Domestic plumbing materials and their effect on viruses

1995 ◽  
Vol 32 (1) ◽  
pp. I-III
Author(s):  
S. Timms ◽  
K. O. Colquhoun ◽  
J. Slade ◽  
C. R. Fricker
Keyword(s):  
Water Supply ◽  
Water Supply Systems ◽  
Domestic Water ◽  
Flow Through ◽  
Virucidal Effect ◽  
Materials Used ◽  
Supply Systems ◽  
Domestic Water Supply

To examine the virucidal effects of various materials used for tubing in domestic water supply systems, experiments have been carried out that examine the recovery percentages of five viruses allowed to flow through pipes made from “aged” samples of five plumbing materials. Most materials had only modest virucidal effect, but copper produced significant reductions in levels of all five viruses.

Study on Resistance Characteristics of Trilobal Throttling Element in Narrow Annular Channel

2017 ◽  
Author(s):  
Wu Youguang ◽  
Li Weihua ◽  
Jia Haijun
Keyword(s):  
Experimental Data ◽  
Turbulence Model ◽  
Annular Channel ◽  
Resistance Coefficient ◽  
Local Resistance ◽  
Function Change ◽  
Local Resistance Coefficient ◽  
Fluent Software ◽  
The Relationship ◽  
Good Agreement

An experimental study was performed to investigate the resistance characteristics of the trilobal throttling element in narrow annular channel, while corresponding flow fields analyzed using Fluent software with RNG k-ε turbulence model based on the structural grid for the trilobal throttling element with different placket angle. A relationship between the packet angle θ and the local resistance coefficient ξ is obtained. Results show that the local resistance coefficient obtained by numerical simulation of the trilobal throttling element in narrow annular channel have a good agreement with the experimental data, and their relative error is less than 8%. This also fully proves that the RNG k-ε turbulence model is suitable for the simulation of the trilobal throttling element in the narrow annular channel. The local resistance coefficient of the trilobal throttling element in narrow annular channel increases with rising packet angle θ, and the relationship is similar to the power function change.

scholarly journals CALCULATIONS OF SHORT PIPELINES TAKING INTO ACCOUNT THE FLOW STABILIZATION

2021 ◽  
pp. 13-17
Author(s):  
Olena Gizha
Keyword(s):  
Water Supply ◽  
Mutual Influence ◽  
Usual Method ◽  
Water Supply Systems ◽  
Local Resistance ◽  
Pressure Losses ◽  
Economic Decisions ◽  
Factors Influencing ◽  
Flow Stabilization ◽  
Supply Systems

Analyzing the existing dependences on the calculation of short pressure pipelines in turbulent mode, significant shortcomings of these recommendations were identified. A physical model of motion is proposed, which explains the processes occurring in the area of stabilization after local resistance and allows to establish the factors influencing its length.Experiments on pipes with different roughness and different pipeline fittings made it possible to analyze the change in kinematic characteristics in the area after resistance. Studies have shown that in short pipes, the length of which is less than the length of the stabilization section, there are less pressure losses than in the calculations by the usual method, when there are simply local and length losses. Dependencies and graphs are given that take into account the mutual influence of local resistances in the case of their location at a distance less than the stabilization area. The proposed recommendations make it possible to make more informed economic decisions when designing short pressure pipelines of various water supply systems.

A Numerical Research of the Resistance Characteristics of the Bottom Nozzle in the Annular Fuel Assembly

2018 ◽  
Author(s):  
Duan Minghui ◽  
Zhao Minfu
Keyword(s):  
Fuel Assembly ◽  
Geometric Model ◽  
Resistance Coefficient ◽  
Local Resistance ◽  
Flow Paths ◽  
Rod Bundle ◽  
Split Ratio ◽  
Local Resistance Coefficient ◽  
Calculation Results ◽  
Numerical Research

The upstream of the bottom nozzle in the annular fuel assembly is the coolant inlet, and the downstream is the fuel rod bundle, which includes both inner and outer coolant flow paths. Therefore, the resistance characteristics of the bottom nozzle are very complex. In order to obtain the nozzle local resistance characteristics, a numerical research has been performed to simulate the bottom nozzle in different flow rates and split ratios with a simplified geometric model by CFX. The calculation results indicated that the local resistance of the bottom nozzle in the annular fuel assembly existed self-modeling phenomenon. The critical Reynolds number wasn’t influenced by the split ratio. The local resistance coefficient of the bottom nozzle was only related to the split ratio. The research has provided an analysis method for the bottom nozzle resistance characteristics research.

scholarly journals МАТЕМАТИЧЕСКАЯ МОДЕЛЬ КОРРОЗИИ ВНУТРИ МЕТАЛЛИЧЕСКИХ ВОДОПРОВОДНЫХ ТРУБ

SWorldJournal ◽  
2018 ◽  
pp. 37-44
Author(s):  
Huy Nguyen ◽  
Ngoc Nguyen
Keyword(s):  
Cast Iron ◽  
Energy Consumption ◽  
Water Supply ◽  
Water Flow ◽  
Water Supply Systems ◽  
Pressure Losses ◽  
Corrosion Intensity ◽  
Supply Systems

In water supply systems, one of the most important factors is corrosion of pipelines from steel and cast-iron pipes, an increase in pressure losses, which reduces water flow and increases energy consumption. Excessive corrosion intensity is determined by

Development of a test method for assessing inactivation of viruses by materials used in domestic plumbing

1995 ◽  
Vol 31 (5-6) ◽  
pp. 181-184
Author(s):  
K. O. Colquhoun ◽  
S. Timms ◽  
A. Maddox ◽  
C. R. Fricker
Keyword(s):  
Water Supply ◽  
Test Method ◽  
Water Supply Systems ◽  
Domestic Water ◽  
Flow Through ◽  
Virucidal Effect ◽  
Materials Used ◽  
Supply Systems ◽  
Domestic Water Supply

To examine the virucidal effect of various materials used for tubing in domestic water supply systems, experiments have been carried out that examine the recovery percentages of five viruses allowed to flow through pipes made from “aged” samples of five plumbing materials. Most materials had only modest virucidal effect, but copper produced significant reductions in levels of all five viruses.

Influence Experiment for the Spacing Distance of Orifice Plates to Local Resistance Coefficient in the Pressure Delivery Pipeline

2015 ◽  
Vol 744-746 ◽  
pp. 1092-1100 ◽  
Author(s):  
Lin Li ◽  
Sheng Jin ◽  
Zhao Liang Bai
Keyword(s):  
Resistance Coefficient ◽  
Head Loss ◽  
Relative Distance ◽  
Local Resistance ◽  
Water Losses ◽  
Head Losses ◽  
Water Head ◽  
Local Resistance Coefficient ◽  
Local Water ◽  
Maximal Relative Error

In order to research the influence rule of the spacing distance between orifice plates to the local resistance coefficient and total local water head losses , carried out the experiment research through set the two different relative distance of orifice plates in the pressure delivery pipeline. The experimental results showed that: When the relative distance, the results of total local water head losses calculated by the traditional hydraulics formula with the real measured data, the maximal relative error was less than 3%. This shown that when the relative distance was big, it was no necessary to consider the influence of the relative distance between orifice plates. However, when the relative distance, the real measured data of the total local water losses was much smaller than the calculated data by the traditional calculation formula, the maximal relative error was reached 239.5%. It was explained that when the relative distance was relative small, existed the adjoining influence between orifice plates, so the total local water losses by the multi-orifice plates was not equal to the sum of each water head loss by the single orifice plate, and the total local head loss was not necessarily increased with the number of orifice plates increasing. Whether or not the increasing total local water head losses was closely related with the relative distance of the orifice plates. The traditional local water head loss calculation formula in the hydraulics should be corrected and modified.

scholarly journals Comparative Analysis of the Efficiency of Methods for Optimizing the Flow Distribution in Water Supply Systems with a Large Number of Active Sources

2020 ◽  
Vol 219 ◽  
pp. 04004
Author(s):  
Sergey Dyadun ◽  
Vladlen Kuznetsov ◽  
Valentin Yesilevskyi
Keyword(s):  
Comparative Analysis ◽  
Water Supply ◽  
Water Flow ◽  
Flow Distribution ◽  
Computer Time ◽  
Water Supply Systems ◽  
Technological Processes ◽  
Operative Control ◽  
The Cost ◽  
Supply Systems

Optimization of the water flow distribution is an important problem in the field of the operative control over technological processes in water supply systems. In this article we describe the comparative analysis results showing the efficiency of various methods used to optimize flow distribution in water supply systems with a large number of active sources. The research has shown that the Hooke and Jeeves method of the direct search is the most efficient in terms of the cost of computer time and the amount of used memory.

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