Surge damping analysis in pipe systems: modelling and experiments

Ramos, Helena; Covas, Dídia; Borga, Alexandre; Loureiro, D.

doi:10.1080/00221686.2004.9728407

Cited by 113 publications

(66 citation statements)

References 16 publications

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“…The classic approach assumes that the pipe-wall has a linear-elastic rheological behaviour, friction losses are described by quasi-steady formulae, flow is one-phase and the pipe is completely constrained axially [2]. These assumptions are not always valid, as there are natural phenomena that rapidly attenuate or increase transient pressures such as fluid friction during fast-transients [4], leaks [5], the mechanical behaviour of plastic pipes [6][7][8], dissolved or entrapped air [9][10][11] and multi-pipe systems.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Flow with Cavitation in Viscoelastic Pipes

Soares¹,

Covas²,

Ramos³

et al. 2009

International Journal of Fluid Machinery and Systems

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The current paper focuses on the analysis of transient cavitating flow in pressurised polyethylene pipes, which are characterized by viscoelastic rheological behaviour. A hydraulic transient solver that describes fluid transients in plastic pipes has been developed. This solver incorporates the description of dynamic effects related to the energy dissipation (unsteady friction), the rheological mechanical behaviour of the viscoelastic pipe and the cavitating pipe flow. The Discrete Vapour Cavity Model (DVCM) and the Discrete Gas Cavity Model (DGCM) have been used to describe transient cavitating flow. Such models assume that discrete air cavities are formed in fixed sections of the pipeline and consider a constant wave speed in pipe reaches between these cavities. The cavity dimension (and pressure) is allowed to grow and collapse according to the mass conservation principle. An extensive experimental programme has been carried out in an experimental set-up composed of high-density polyethylene (HDPE) pipes, assembled at Instituto Superior Técnico of Lisbon, Portugal. The experimental facility is composed of a single pipeline with a total length of 203 m and inner diameter of 44 mm. The creep function of HDPE pipes was determined by using an inverse model based on transient pressure data collected during experimental runs without cavitating flow. Transient tests were carried out by the fast closure of the ball valves located at downstream end of the pipeline for the non-cavitating flow and at upstream for the cavitating flow. Once the rheological behaviour of HDPE pipes were known, computational simulations have been run in order to describe the hydraulic behaviour of the system for the cavitating pipe flow. The calibrated transient solver is capable of accurately describing the attenuation, dispersion and shape of observed transient pressures. The effects related to the viscoelasticity of HDPE pipes and to the occurrence of vapour pressures during the transient event are discussed.

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Section: Introductionmentioning

confidence: 99%

Unsteady Flow with Cavitation in Viscoelastic Pipes

Soares¹,

Covas²,

Ramos³

et al. 2009

International Journal of Fluid Machinery and Systems

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“…Como se tratava de uma adutora hipotética, os resultados numéricos obtidos com a consideração do modelo viscoelástico linear foram comparados com aqueles resultantes do modelo da coluna elástica. Além disso, para verificar a adequabilidade do modelo proposto ao sistema hipotético, partiu-se do pressuposto de que o simulador hidráulico em transientes produzidos por interrupção no bombeamento deveria reproduzir os mesmos efeitos de atenuação e dispersão da onda de pressão que os observados por Ramos et al (2004), Covas et al (2005) …”

Section: Metodologiaunclassified

“…Essa aproximação é satisfatória para tubos de metal e concreto. Entretanto, conforme atestam Rieutord e Blanchard (1979), Gally, Güney e Rieutord (1979), Ramos et al (2004), Covas et al (2005) (2012) utilizaram o modelo viscoelástico linear para condutos plásticos e obtiveram resultados satisfatórios para o caso de transientes provocados por fechamento de válvula. Nesses casos, lograram êxito ao incorporar ao modelo hidromecânico os efeitos de dispersão e amortecimento da onda de pressão, característicos dos dados experimentais observados.…”

Section: Introductionunclassified

Modelagem computacional do Golpe de Aríete em condutos plásticos

Ferreira¹,

Barbosa²,

Castro³

2016

RDAE

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ResumoO dimensionamento impreciso de condutos plásticos de adução torna o sistema vulnerável ao golpe de aríe-te. O emprego de modelos mais precisos para a descrição do comportamento dos condutos conduz a melhorias sensíveis no seu dimensionamento. Assim, esta pesquisa propõe uma adaptação do modelo viscoelástico a condutos pressurizados sujeitos a transientes gerados por falha no bombeamento. O modelo foi implementado, para fins de teste, em um módulo computacional, utilizado para simulação do golpe de aríete em adutoras. As simulações foram realizadas em uma adutora hipotética composta por um conjunto motobomba a montante e um reservatório a jusante, com condutos de material PVC. Os resultados confirmaram os efeitos esperados de atenuação e dispersão da onda de pressão, indicando que previsões com base no modelo viscoelástico resultam em um dimensionamento economicamente menos dispendioso. Palavras

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“…According to the same type of analysis, in a plastic pipe with a non-elastic behaviour (e.g., PVC, HDPE), the pipe-wall retarded-behaviour is mainly responsible for the pressure damping. Thus, the energy dissipation can adequately be reproduced with mathematic transformations using Equation (13) [43,44]:…”

Section: Damping Effectsmentioning

confidence: 99%

“…This damping can be a combined effect of the non-elastic behaviour of the pipe-wall and the unsteady friction effect, depending essentially upon the pipe material [43]. This technique aims at the characterization of energy dissipation through the variation of the extreme piezometric head over time [6,[43][44][45].…”

Section: Damping Effectsmentioning

confidence: 99%

PATs Operating in Water Networks under Unsteady Flow Conditions: Control Valve Manoeuvre and Overspeed Effect

Sánchez

Jiménez

Ramos

2018

Water

Self Cite

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Abstract:The knowledge of transient conditions in water pressurized networks equipped with pump as turbines (PATs) is of the utmost importance and necessary for the design and correct implementation of these new renewable solutions. This research characterizes the water hammer phenomenon in the design of PAT systems, emphasizing the transient events that can occur during a normal operation. This is based on project concerns towards a stable and efficient operation associated with the normal dynamic behaviour of flow control valve closure or by the induced overspeed effect. Basic concepts of mathematical modelling, characterization of control valve behaviour, damping effects in the wave propagation and runaway conditions of PATs are currently related to an inadequate design. The precise evaluation of basic operating rules depends upon the system and component type, as well as the required safety level during each operation.

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Surge damping analysis in pipe systems: modelling and experiments

Cited by 113 publications

References 16 publications

Unsteady Flow with Cavitation in Viscoelastic Pipes

Unsteady Flow with Cavitation in Viscoelastic Pipes

Modelagem computacional do Golpe de Aríete em condutos plásticos

PATs Operating in Water Networks under Unsteady Flow Conditions: Control Valve Manoeuvre and Overspeed Effect

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