Investigation of Hydraulic Transients in a Pipeline with Column Separation

Adamkowski, Adam; Lewandowski, Mariusz

doi:10.1061/(asce)hy.1943-7900.0000596

Cited by 63 publications

(33 citation statements)

References 8 publications

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“…From that study, nine courses were selected for the comparisons being made in this study (Table 2). However, in the study of 2012 [12], the same authors showed different results obtained on a slightly modified test bench, in which cavitation-related column separation occurred. In the comparative tests presented below, six courses obtained then were used (Table 3).…”

Section: Academy Of Sciences In Gdańsk In Their Paper Of 2006mentioning

confidence: 95%

Computational compliance criteria in water hammer modelling

Urbanowicz

2017

E3S Web Conf.

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Abstract. Among many numerical methods (finite: difference, element, volume etc.) used to solve the system of partial differential equations describing unsteady pipe flow, the method of characteristics (MOC) is most appreciated. With its help, it is possible to examine the effect of numerical discretisation carried over the pipe length. It was noticed, based on the tests performed in this study, that convergence of the calculation results occurred on a rectangular grid with the division of each pipe of the analysed system into at least 10 elements. Therefore, it is advisable to introduce computational compliance criteria (CCC), which will be responsible for optimal discretisation of the examined system. The results of this study, based on the assumption of various values of the Courant-Friedrichs-Levy (CFL) number, indicate also that the CFL number should be equal to one for optimum computational results. Application of the CCC criterion to own written and commercial computer programmes based on the method of characteristics will guarantee fast simulations and the necessary computational coherence.

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Section: Academy Of Sciences In Gdańsk In Their Paper Of 2006mentioning

confidence: 95%

Computational compliance criteria in water hammer modelling

Urbanowicz

2017

E3S Web Conf.

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“…The knowledge of the maximum pressure values p 1 to p n and the timing of their appearance t 1 to t n helped two parameters P max and T max to be set. In a simplified manner, these parameters signalled the fitting of simulation results to the experimental ones:

P max = \frac{0true \sum_{i = 1}^{n} (||, \frac{p_{i s} - p_{i e}}{p_{i e}}) \cdot 100 %}{n},

T max = \frac{0true \sum_{i = 1}^{n} (||, \frac{t_{i s} - t_{i e}}{t_{i e}}) \cdot 100 %}{n} .

Comparative experimental tests were conducted by Adamkowski and Lewandowski on a test stand constructed at the Institute of Fluid‐Flow Machinery in Gdańsk (Figure ). Four representative pressure runs were selected for comparison.…”

Section: Does the Weighting Function Need To Be Precise?mentioning

confidence: 99%

Fast and accurate modelling of frictional transient pipe flow

Urbanowicz

2018

Z Angew Math Mech

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This paper is devoted to the one‐dimensional (1D) modelling of hydraulic losses during transient flow of liquids in pressure lines. Unsteady pipe wall shear stress is present in the form of a convolution of liquid acceleration with a weighting function. The weighting function depends on the dimensionless time and the Reynolds number. In the original model of Zielke (1968), computation of the convolution integral had a complex and inefficient mathematical structure (featured power growth of computational time). Therefore, further work aimed at developing efficient models for estimation of unsteady hydraulic resistance (with nearly linear growth of computational time). In the present paper, a correction to the erratic recursive formula by Schohl (1993), being used to calculate the unsteady wall shear stresses during transient flow, is presented. The simulation results obtained with the corrected Schohl's recursive formula are consistent with the classic but computationally inefficient formula proposed recently by Vardy and Brown (2010). The accuracy of the efficient weighting function obtained in wall shear stress models is verified. The results of pressure pulsation obtained when taking into account cavitating flow, or not, are surprising in the sense that the weighting function does not need to be built by a lengthy sum of exponential terms to accurately simulate the transient event.

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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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Investigation of Hydraulic Transients in a Pipeline with Column Separation

Cited by 63 publications

References 8 publications

Computational compliance criteria in water hammer modelling

Computational compliance criteria in water hammer modelling

Fast and accurate modelling of frictional transient pipe flow

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

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