Charts for water hammer in pipelines resulting from valve closure

1980 ◽  
Vol 7 (2) ◽  
pp. 243-255 ◽  
Author(s):  
Eugen Ruus ◽  
Farouk A. El-Fitiany
Keyword(s):  
Pipe Wall ◽  
Pressure Head ◽  
Water Hammer ◽  
Wall Friction ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Closure Time ◽  
Basic Parameters

Maximum pressure head rises, which result from valve closure according to (a) uniform, (b) equal-percentage, and (c) optimum valve closure arrangements, are calculated and plotted for the valve end and for the midpoint of a simple pipeline. Basic parameters such as the pipeline constant, relative closure time, and pipe wall friction are considered for closures both from partial as well as from full valve openings. The results of this paper can be used to draw the maximum hydraulic grade line along the pipe for these closure arrangements. It is found that the equal-percentage closure arrangement yields consistently less pressure head rise than does the uniform closure arrangement. Further, the optimum closure arrangement yields consistently less head rise than the equal-percentage one. Closures from partial valve openings increase the pressure head rise considerably and must always be considered.

Charts for water hammer in pipelines resulting from valve closure from full opening only

1985 ◽  
Vol 12 (2) ◽  
pp. 241-264 ◽  
Author(s):  
Bryan W. Karney ◽  
Eugen Ruus
Keyword(s):  
Good Accuracy ◽  
Pipe Wall ◽  
Pressure Head ◽  
Wall Friction ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Closure Time ◽  
Basic Parameters ◽  
Valve Opening ◽  
Open Position

Maximum pressure head rises, which result from total closure of the valve from an initially fully open position, are calculated and plotted for the valve end and for the midpoint of a simple pipeline. Uniform, equal-percentage, optimum, and parabolic closure arrangements are analysed. Basic parameters such as pipeline constant, relative closure time, and pipe wall friction are considered with closures from full valve opening only. The results of this paper can be used to draw the maximum hydraulic grade line along the pipe with good accuracy for the closure arrangements considered. It is found that the equal-percentage closure arrangement yields consistently less pressure head rise than does the parabolic closure arrangement. Further, the optimum closure arrangement yields consistently less head rise than the equal-percentage one. Uniform closure produces pressure head rise that usually lies between those produced by the parabolic and the equal-percentage closure arrangements, except for the range of low pressure head rise combined with low or zero friction, where the rise due to uniform closure approaches that produced by optimum closure.

Charts for water hammer in high head pump discharge lines resulting from pump failure and check valve closure

1985 ◽  
Vol 12 (1) ◽  
pp. 137-149 ◽  
Author(s):  
Eugen Ruus ◽  
Bryan Karney
Keyword(s):  
Check Valve ◽  
Pressure Head ◽  
Major Effect ◽  
Wall Friction ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Pump Failure ◽  
Basic Parameters ◽  
High Head ◽  
Computer Studies

Maximum pressure head drops and rises resulting from pump failure and subsequent check valve closure are calculated and plotted for a simple pump discharge line at pump end, midpoint, and three-quarter point. Basic parameters such as pipeline constant, pipe wall friction, complete pump characteristics, and pump inertia constant are accounted for in the analyses. Computer studies indicate that pipe friction, pipeline constant, and pump inertia have a major effect on pressure head drops and rises.Studies indicate further that whereas for large pump inertia the pressure head rise or drop at the midpoint is only moderately larger than one-half of the rise or drop at pump end, for small pump inertia this difference is much greater. For very small pump inertia, the pressure head drop or rise at midpoint approaches the values at pump end. This increase in pressure head drop and rise for very small pump inertia is even more pronounced at the three-quarter point.

Maximum Pressure Head Due to Linear Valve Closure

1991 ◽  
Vol 113 (4) ◽  
pp. 643-647 ◽  
Author(s):  
Chyr Pyng Liou
Keyword(s):  
Flow Characteristic ◽  
Pressure Head ◽  
Head Loss ◽  
Water Hammer ◽  
Point Of View ◽  
Global Perspective ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Subtle Effect ◽  
Dimensionless Variables

The maximum pressure head resulting from one-speed closure of wide open valves is investigated. The dimensionless variables formulated in this study make the subtle effect of the initial valve head loss explicit and separate from that of the pipe frictional head loss. The maximum head is related to initial pipe frictional head loss, the initial valve head loss, the inherent flow characteristic of the valve, and the closure period by plots of dimensionless variables. The trends of the variation of the maximum pressure head are discussed. An example is used to illustrate the usage of the plots, and to show the advantage of having a global perspective of the phenomenon in the selection and sizing of valves from the water hammer point of view.

Charts for water hammer in pipelines with air chambers

1977 ◽  
Vol 4 (3) ◽  
pp. 293-313 ◽  
Author(s):  
Eugen Ruus
Keyword(s):  
Water Column ◽  
Pipe Wall ◽  
Water Hammer ◽  
Wall Friction ◽  
Low Resistance ◽  
Discharge Line ◽  
Air Chamber ◽  
Basic Parameters ◽  
Computer Studies

Upsurges and downsurges are calculated and plotted for a simple pump discharge line provided with an air chamber. Basic parameters such as pipeline constant, air chamber parameter, pipe wall friction, and orifice resistance are used. The results of this paper can be used to determine the necessary volume of the air chamber. Computer studies indicate that the assumption of the rigid water column and the concentration of pipe friction at the pump end of the pipeline yields reasonably good results at the pump end; however, because of these assumptions, large errors in estimation of both upsurges and downsurges occur at the midpoint and particularly at the quarter point of the pipeline. Pipe friction has a substantially different effect on surges than that of the orifice resistance; these two effects should therefore be considered separately. A differential orifice is recommended and considered; this orifice should have a low resistance to flow out of the chamber.

Understanding Line Packing in Frictional Water Hammer

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Jim C. P. Liou
Keyword(s):  
Numerical Methods ◽  
Wave Front ◽  
Water Hammer ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Governing Equations ◽  
Front Line ◽  
Wave Fronts ◽  
Friction Term

For valve closure transients in pipelines, friction attenuates the amplitude of water hammer wave fronts and causes line packing. The latter is a sustained head increase behind the wave front. Line packing can lead to overpressure. Because of the nonlinearity of the friction term in the governing equations of water hammer, a satisfactory analytical explanation of line packing is not available. Although numerical methods can be used to compute line packing, an analytical explanation is desirable to better understand the phenomenon. This paper explains line packing analytically and presents a formula to compute the line packing that leads to the maximum pressure at the closed valve.

scholarly journals An Analysis of the Impact of Valve Closure Time on the Course of Water Hammer

2016 ◽  
Vol 63 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Apoloniusz Kodura
Keyword(s):  
Transient Flow ◽  
Pressure Change ◽  
Water Hammer ◽  
Valve Closure ◽  
Calculation Methods ◽  
New Methods ◽  
Closure Time ◽  
Physical Experiments ◽  
Comparison Of The Results ◽  
The Impact

Abstract The knowledge of transient flow in pressure pipelines is very important for the designing and describing of pressure networks. The water hammer is the most common example of transient flow in pressure pipelines. During this phenomenon, the transformation of kinetic energy into pressure energy causes significant changes in pressure, which can lead to serious problems in the management of pressure networks. The phenomenon is very complex, and a large number of different factors influence its course. In the case of a water hammer caused by valve closing, the characteristic of gate closure is one of the most important factors. However, this factor is rarely investigated. In this paper, the results of physical experiments with water hammer in steel and PE pipelines are described and analyzed. For each water hammer, characteristics of pressure change and valve closing were recorded. The measurements were compared with the results of calculations perfomed by common methods used by engineers - Michaud’s equation and Wood and Jones’s method. The comparison revealed very significant differences between the results of calculations and the results of experiments. In addition, it was shown that, the characteristic of butterfly valve closure has a significant influence on water hammer, which should be taken into account in analyzing this phenomenon. Comparison of the results of experiments with the results of calculations? may lead to new, improved calculation methods and to new methods to describe transient flow.

Charts for water hammer in low head pump discharge lines resulting from water column separation and check valve closure

1984 ◽  
Vol 11 (4) ◽  
pp. 717-742 ◽  
Author(s):  
Eugen Ruus ◽  
Bryan Karney ◽  
Farouk A. El-Fitiany
Keyword(s):  
Water Column ◽  
Pressure Rise ◽  
Check Valve ◽  
Pressure Head ◽  
Maximum Pressure ◽  
Valve Closure ◽  
High Point ◽  
Column Separation ◽  
Discharge Line ◽  
Low Head

Maximum pressure head rises resulting from water column separation and check valve closure are calculated and plotted for a simple low head pump discharge line with one well-defined high point. Basic parameters such as pipeline constant, pipe wall friction, complete pump characteristics, pump inertia constant, and the relative location of the high point are accounted for in the analyses. The results of this paper can be used to determine (a) when water column separation is expected, (b) how to avoid water column separation, and (c) the necessary wall thickness in cases where no protection against water column separation is provided. Computer studies indicate that both the vertical and horizontal location of the high point as well as the pipe friction, the pipeline constant, and the pump inertia have a major effect on pressure head rises. Water column separation does not always constitute a danger to the pipeline. Key words: waterhammer, water column separation, check valve closure, pressure rise, pump discharge line, chart.

Investigation on Redesigning Strategies for Water-Hammer Control in Pressurized-Piping Systems

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Mohamed Fersi ◽  
Ali Triki
Keyword(s):  
Numerical Solution ◽  
Transient Flow ◽  
Pipe Wall ◽  
Pressure Head ◽  
Water Hammer ◽  
Piping System ◽  
Proposed Model ◽  
Piping Systems ◽  
Control Water ◽  
Short Section

This paper explored and compared the effectiveness of the inline and the branching redesign strategies used to control water-hammer surges initiated into existing steel piping systems. The piping system is handled, at its transient sensitive regions, by replacing an inline, or adding a branching, short-section made of high- or low-density polyethylene (HDPE or LDPE) pipe-wall materials. The Ramos model was used to describe the transient flow, along with the method of characteristics implemented for numerical computations. The comparison of the numerical solution with experimental data available from the literature and alternative numerical solution evidenced that the proposed model could reproduce satisfactorily the magnitude and the phase shift of pressure head evolution. Further, the robustness of the proposed protection procedures was tested with regard to water-hammer up- and down-surge mechanisms, taken separately. Results demonstrated that both utilized techniques provided a useful tool to soften both water-hammer up- and down-surges. Additionally, the amortization of pressure-head-rise and -drop was sensitive to the short-section material and size. Moreover, the branching strategy illustrated several enhancements to the inline one in terms of period spread-out limitation, while providing acceptable pressure-head damping.

Effect of multi-valve closure on superposed pressure in a tree-type long distance gravitational water supply system

2019 ◽  
Vol 68 (6) ◽  
pp. 420-430
Author(s):  
Xingtao Wang ◽  
Jian Zhang ◽  
Xiaodong Yu ◽  
Sheng Chen ◽  
Wenlong Zhao ◽  
...  
Keyword(s):  
Water Supply ◽  
Pressure Rise ◽  
Water Hammer ◽  
Supply System ◽  
Water Supply System ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Long Distance ◽  
Maximum Water ◽  
Tree Type

Abstract Valves are installed at the end of each branch pipeline in a tree-type long distance gravitational water supply system to regulate flow. However, the sequential closing of all valves may cause a tremendous superposed pressure rise, even larger than the pressure rise under simultaneous valve closure. In this paper, the effects of sequential valve closure on the superposed maximum water hammer pressure rise in a pipeline were investigated. By using the wave superposition principle, a sequential valve closure formula leading to maximum water hammer was proposed and verified using numerical simulation based on a practical project. In addition, the superposed maximum pressure rises in the pipeline were compared under single, simultaneous and sequential valve closure, respectively. The results show that the sequential valve closure formula agrees well with the numerical results and the pressure rise in the pipeline under the sequential closing was the largest. Moreover, compared with the superposed maximum pressure rises at the main pipeline, the effect of sequential valve closure on superposed maximum pressure rise at the branch pipeline is more sensitive.

Controlling Surge Due to Shut-Off Fast Closing Valve at the End of an Oil Pipeline

2006 ◽  
Author(s):  
Wei Wang ◽  
Jing Gong
Keyword(s):  
Control Measures ◽  
Maximum Pressure ◽  
Operating Parameters ◽  
Valve Closure ◽  
Oil Pipeline ◽  
Closure Time ◽  
Pump Station ◽  
Surge Control ◽  
Relief System ◽  
Product Pipeline

Surge will be induced in oil transfer pipeline, due to the changes of transportation materials, operating parameters or pump station equipments. However, the surge induced by Shut-off fast closing valve could be more destructive, for the duration of valve closure time is short, and then the maximum pressure of the surge is much higher, so it’s necessary to control the surge. Based on the characteristic method, this paper establishes a numerical calculation of the accidental Shut-off the terminal fast closing valve at an product pipeline, and simulates the corresponding transient process of pipeline pressure. Upon the upper result, a further research, which combines the boundary condition of surge relief system, is carried out, in order to get the optimal surge control measures through the relief system.

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