Waterhammer Analysis—Essential and Easy (and Efficient)

Wood, Don J.

doi:10.1061/(asce)0733-9372(2005)131:8(1123)

Cited by 53 publications

(35 citation statements)

References 5 publications

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“…Esto implica, en comparación con la discretización adoptada originalmente en la red ejemplo, una disminución de 95.2% en el caso de ∆t, y un incremento de 2117% en el caso del N total. En otras palabras, en orden a conseguir un mejor resultado, el MC necesariamente debe afinar (reducir) el tamaño de ∆x en cada tramo (Wood, 2005), pasando en el ejemplo analizado de ∆x = 16.20 m a ∆x = 0.73 m (ambos valores promedio), con el consiguiente impacto en la cantidad de cálculos a realizar en cada paso de tiempo. Por esta razón resulta menos costoso aplicar metodologías que sean reconocida y probadamente más precisas (y conservadoras) que el MC cuando C n < 1 en la mayoría de los tramos, por lo que desde un punto de vista ingenieril, y siempre por el lado de la seguridad, es conveniente saber cuáles métodos son los que entregan la mayor amplitud de rango entre las cotas piezométricas extremas (positivas y negativas) frente a un mismo evento transitorio.…”

Section: Discussionunclassified

“…(Salgado, 1992). El MC es fácil de usar, rápido y explícito, lo cual permite calcular las variables de estado y directamente a partir de valores previamente conocidos en el paso de tiempo anterior (Watters, 1984 (4) en sistemas complejos, lo cual puede limitar la magnitud del paso de tiempo computacional (∆ ) común para toda la red de tuberías, por lo que algunas veces es común: (i) recurrir a la modificación de hasta un límite típico de 6 m (Wood, 2005); y/o (ii) modificar en un rango máximo de ±15% (Wylie y Streeter, 1978). Otro camino de solución es mantener inalteradas las (4)…”

Section: Método De Las Características (Explícito 1er Orden)unclassified

“…En general, el MC entrega un resultado numérico exacto cuando C n = a·∆t / ∆x = 1.0; de otra forma, genera resultados en la forma de atenuaciones (cuando C n = a·∆t / ∆x < 1.0) o inestabilidad numérica (cuando C n = a·∆t / ∆x >1.0). Es difícil satisfacer la ecuación (4) en sistemas complejos, lo cual puede limitar la magnitud del paso de tiempo computacional (∆t) común para toda la red de tuberías, por lo que algunas veces es común: (i) recurrir a la modificación de L hasta un límite típico de 6 m (Wood, 2005); y/o (ii) modificar a en un rango máximo de ± 15% (Wylie y Streeter, 1978). Otro camino de solución es mantener inalteradas las condiciones iniciales y aplicar interpolación numérica con el riesgo de generar errores en la solución debido a la disipación y dispersión numérica (Goldberg y Wylie, 1983).…”

Section: Método De Las Características (Explícito 1er Orden)unclassified

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Análisis del golpe de ariete en un sistema de distribución de agua

Twyman¹

2017

ing.agua

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Section: Discussionunclassified

Section: Método De Las Características (Explícito 1er Orden)unclassified

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Análisis del golpe de ariete en un sistema de distribución de agua

Twyman¹

2017

ing.agua

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“…These negative pressuresmaydamage the pipe systemwhichincludesstructural buckling or collapse and failing of pipe joints [3], contamination of potable water [4],and vaporous cavitation or liquid column separation which could result in column separation with large water hammer pressures [5].Numerous works have been reported on pump-pipe lines that were subjected to transients. Notable works are from [6], [7], [8], [9], [10].…”

Section: Literature Reviewmentioning

confidence: 99%

Analysis of Pump-Pipe Line System Using Elastic Theory of Fluid Transients

Nerella¹,

Rathnam

2015

IJRET

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The conditions like pump trip or power failure to pumps can create the extreme pressure fluctuations in pump-pipeline systems which may be the case of increase in maximum pressure head or decrease in minimum pressure head and even reaching to subatmospheric pressure conditions.Simulation of these extreme events could help the designer to take necessary precautions like increasing the thickness of the pipeline orproviding suitablesurge protection devices for the entire pump-pipeline system. Due to complexity nature of hyperbolic partial differential equations involved to describe these extreme events, various numerical methods were available.One such numerical method is called the method of characteristics (MOC) and is widely used to compute the fluid transients which may occur in pump-pipeline system. The objective of the study in the present paper is to analyze hydraulic transient pressuresfor the case of power trip to pumps byusing Elastic theory based on MOCapproach. A case study of J.C.R.Devadula Lift scheme in Telangana State, India is presented. It is observed that water column separation has occurred on downstream of pump delivery and hence transient control device like air vessels and one-way surge tanks are to be planned for this pipeline system.

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“…With advances in computer technology, numerical simulations have become widely employed in water hammer analyses [13] to [15]. To predict pressure variations in a water supply system and to choose appropriate water hammer preventive measures, numerical simulations of water hammer surges are indispensable, simple, and effective [16]. Methods of numerically analysing water hammer surges include arithmetic, graphical, algebraic and linear analysis methods as well as the method of characteristics (MOC).…”

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confidence: 99%

Numerical Simulation of Transient Pressure Control in a Pumped Water Supply System Using an Improved Bypass Pipe

Li¹,

Man-lin²,

Xie³

2016

SV-JME

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614 BACKGROUNDPump failures induce rapid changes in the flow rate, which causes extremely high-pressure water hammer surges in the water supply system, including extremely high-and low-pressure water hammer surges. Extreme water hammer pressure damages pipes and hydraulic equipment and results in water supply service interruptions. To eliminate or reduce the impact of extreme water hammer pressure on water delivery systems, water hammer prevention measures are normally implemented; these include bypass pipes, air valves, check valves, air tanks, pressure regulating chambers, unidirectional pressure regulating chambers, pressure discharge valves, water hammer prevention valves, etc.[1] to [3]. An air valve is a common, economical, and effective piece of water hammer prevention equipment that is normally installed at the local peak of a pipe. When negative pressure occurs inside the pipe, the air valve opens to allow air in; when the pressure inside the pipe increases, the air valve releases it by discharging air [4] and [5]. A check valve is an economical and reasonable water hammer prevention measure that is widely used in pumping stations [6]. Check valves can prevent water pumps from rotating in reverse due to liquid backflow and thus prevent damage to the motor. However, instant check valve closure results in a catastrophically high pressure [7] and [8]. Therefore, when a check valve is installed in a pumping station to control transients, an air tank should also be installed near the pumping station to prevent the increase in pressure that results from closing the check valve [9]. However, air tanks have drawbacks that include their large volume, high maintenance cost and complex operation (the gas in the tank should be replenished). A pressure discharge valve with the proper parameters can prevent a water delivery system from generating excessively high or low pressures; otherwise, the negative impact of water hammer surges on the water delivery system is exacerbated [10]. To ensure proper protection of a water delivery system by a pressure discharge valve, the pressure discharge valve should have so little inertia that it can be opened promptly in response to a rapid change in the pressure to prevent delays in its opening [11]. A water hammer

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Waterhammer Analysis—Essential and Easy (and Efficient)

Cited by 53 publications

References 5 publications

Análisis del golpe de ariete en un sistema de distribución de agua

Análisis del golpe de ariete en un sistema de distribución de agua

Analysis of Pump-Pipe Line System Using Elastic Theory of Fluid Transients

Numerical Simulation of Transient Pressure Control in a Pumped Water Supply System Using an Improved Bypass Pipe

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