Surge damping analysis in pipe systems: modelling and experiments

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

doi:10.1080/00221686.2004.9641209

Cited by 53 publications

(11 citation statements)

References 18 publications

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“…Time and space responses of the equations to model the pressure and vacuum waves across the tunnels with and without surge tank agree with theory of fast and slow valve closure. The variation of the peak pressure and vacuum waves agreed with the findings of Ramos et al (2004). The benefit-cost ratio is utilized as the objective function in the GA, which is maximized.…”

Section: Discussionsupporting

confidence: 68%

“…A noticeable shift in both peak pressure and vacuum in Fig. 6 is attributable to the considerable difference in the estimated wave speed for a large steel tunnel (with predominant elastic behavior in this paper) and the small-scale plastic pipes (with viscoelastic behavior) considered in Ramos et al (2004).…”

Section: Resultsmentioning

confidence: 82%

“…In Fig. 6, the calculated peak pressure and vacuum are normalized with the overhead of Joukowski (Hjk ¼ aQ o =gA) and compared with the Ramos et al (2004) results. They have studied the peak pressure and vacuum attributable to fast and slow valve closures using a viscoelastic hypothesis for surge damping in the plastic pipes.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Design-Variable Optimization of Hydropower Tunnels and Surge Tanks Using a Genetic Algorithm

Fathi-Moghadam

Haghighipour

Mohammad

et al. 2013

J. Water Resour. Plann. Manage.

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Optimal design of tunnels and surge tanks is a major concern in the implementation and operation of large hydropower plants, particularly those in which tunnels are long and water hammer is likely. In this paper, flow simulation and an optimization process have been linked in an iterative manner to develop a general model for the optimal design of hydropower tunnels and surge tanks for the emergency condition of operation (maximum surge pressure). The governing equations for the analysis of transient flow in conduits are solved using a finite difference scheme. Furthermore, a genetic algorithm (GA) optimization technique is utilized to select the optimal diameter for the headrace tunnel, penstocks, and surge tanks. The benefit-cost ratio is considered as the objective function in the optimization analysis. The proposed method was used to design diameters for Marun hydropower tunnels (an in-operation large hydropower dam located in southwest Iran). The results were compared with results from a nonlinear optimization technique. They revealed considerable savings in construction cost, attributable to the application of GA. The calculated pressures across the tunnels with and without surge tank agree with valve closure theory and previous studies. The model is able to optimize diameters for a branching system of tunnels and penstocks with surge tanks.

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Section: Discussionsupporting

confidence: 68%

Section: Resultsmentioning

confidence: 82%

See 1 more Smart Citation

Design-Variable Optimization of Hydropower Tunnels and Surge Tanks Using a Genetic Algorithm

Fathi-Moghadam

Haghighipour

Mohammad

et al. 2013

J. Water Resour. Plann. Manage.

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“…Such differences can be ascribed to the damping of pressure waves, traveling from node V to node J and vice versa, mainly due to pipe viscoelasticity and unsteady friction (Meniconi et al 2009a). According to Ramos et al (2004) and Soares et al (2008), such a damping has been estimated experimentally in a straight pipe. In particular, as described in Meniconi et al (2010a), the damping of pressure waves traveling between two generic sections in the main pipe at a distance L* can be measured by considering the damping factor k t defined as…”

Section: Sizing Of Illegal Branches By Simple Modelsmentioning

confidence: 99%

Transient tests for locating and sizing illegal branches in pipe systems

Meniconi

Brunone

Ferrante

et al. 2011

Journal of Hydroinformatics

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In pipe systems illegal branches can take away remarkable water resources with negative effects from both the economic and technical points of view. Difficulties in pointing out illegal branches by means of steady-state pressure and discharge measurements are mainly due to the fact that, of course, such systems are not active according to a regular time schedule. In this paper the possibility of using Transient Test-Based Techniques (TTBT) for the location and sizing of branches is shown. Specifically, tests carried out in different branched pipe systems at the Water Engineering Laboratory of the University of Perugia, Italy, show that TTBT allow us to detect branches irrespective of whether they are active or not. To improve the precision of the localization, arrival times of pressure waves are detected by means of wavelet analysis. Finally, a simple relation based on the water hammer theory is proposed to size the branch reliably.Key words 9 9 9 9 apparent losses, illegal connections, pipe system, transient

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“…Results obtained by most commercial software are based on the classic water hammer theory; these are satisfactory to estimate extreme pressures and allow the design of surge-protection devices. However, such models are frequently very imprecise for the analysis and diagnosis of existing systems (Ramos et al 2004;Covas et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Damping Analysis of Hydraulic Transients in Pump-Rising Main Systems

2013

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This paper focuses on the analysis of unsteady pipe flows caused by a pump trip in a water pipeline system. Field experiments have been carried out to collect transient pressure and steady-state flow rate data in the Prado-Instituto Politécnico da Guarda (IPG) pumping system located in Guarda, Portugal. Observed transient pressures were compared with numerical results. Results obtained were excellent both in terms of damping and phase shift of the transient pressure signal, provided that unsteady friction effects were taken into account and an appropriate downstream end boundary condition was considered. The downstream end boundary condition was described by small tanks with variable level and with free discharge into the storage tank; the variation of water level in these small tanks results in the relief of extreme transient pressures (conversely to what is observed in the line-packing effect) and changes the shape of transient pressure waves. This analysis has shown that classical water hammer theory (neglecting unsteady friction) and the consideration of a constant-level reservoir at the downstream end do not accurately describe the observed transient behavior of pressurized pipe systems.

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Surge damping analysis in pipe systems: modelling and experiments

Cited by 53 publications

References 18 publications

Design-Variable Optimization of Hydropower Tunnels and Surge Tanks Using a Genetic Algorithm

Design-Variable Optimization of Hydropower Tunnels and Surge Tanks Using a Genetic Algorithm

Transient tests for locating and sizing illegal branches in pipe systems

Damping Analysis of Hydraulic Transients in Pump-Rising Main Systems

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