The dynamic effect of pipe-wall viscoelasticity in hydraulic transients. Part II—model development, calibration and verification

Covas, Dídia; Stoianov, Ivan; Mano, J. F.; Ramos, Helena; Graham, Nigel; Maksimović, Č.

doi:10.1080/00221680509500111

Cited by 220 publications

(150 citation statements)

References 24 publications

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“…1 and 2, respectively). Since the flow velocity and pressure (dependent variables) in transient flows are functions of time and space (independent variables), these equations are a set of two hyperbolic partial differential equations [1][2][3]7]:…”

Section: Viscoelastic Modelmentioning

confidence: 99%

“…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%

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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: Viscoelastic Modelmentioning

confidence: 99%

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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“…These techniques are referred to as internal or inferential methods. One of the first methods was introduced by Ligget and Chen [24] and have since been derived in a number of techniques [8,9,13,14,22,28,33]. These methods are able to take advantage of the interconnectivity of networks to reduce the number of sensors required.…”

Section: Introductionmentioning

confidence: 99%

Model falsification diagnosis and sensor placement for leak detection in pressurized pipe networks

Goulet

Coutu

Smith

2013

Advanced Engineering Informatics

107

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Pressurized pipe networks used for fresh-water distribution can take advantage of recent advances in sensing technologies and data-interpretation to evaluate their performance. In this paper, a leak-detection and a sensor placement methodology are proposed based on leak-scenario falsification. The approach includes modeling and measurement uncertainties during the leak detection process. The performance of the methodology proposed is tested on a full-scale water distribution network using simulated data. Findings indicate that when monitoring the flow velocity for 14 pipes over the entire network (295 pipes) leaks are circumscribed within a few potential locations. The case-study shows that a good detectability is expected for leaks of 50 L/min or more.A study of measurement configurations shows that smaller leak levels could also be detected if additional pipes are instrumented.

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The dynamic effect of pipe-wall viscoelasticity in hydraulic transients. Part II—model development, calibration and verification

Cited by 220 publications

References 24 publications

Unsteady Flow with Cavitation in Viscoelastic Pipes

Unsteady Flow with Cavitation in Viscoelastic Pipes

Modelagem computacional do Golpe de Aríete em condutos plásticos

Model falsification diagnosis and sensor placement for leak detection in pressurized pipe networks

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