Evaluation of transient effects in the pressure-time method

Saemi, Simindokht; Sundstrom, L.R. Joel; Cervantes, Michel; Raisee, Mehrdad

doi:10.1016/j.flowmeasinst.2019.101581

Cited by 6 publications

(17 citation statements)

References 20 publications

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“…This paper presents a study of the water hammer phenomenon and the pressure-time method for a straight pipe with 40 m length, inspired by Ref [5]. The cross-section is constant, with an internal diameter of 300 mm.…”

Section: Test Casementioning

confidence: 99%

“…In this method, the pressure is measured between two cross-sections during a deceleration of the liquid mass by closing a valve or turbine wicket gates to obtain the initial At the beginning of the valve closure, the flow is quasi-steady. However, close to the end time of valve closure, the flow is unsteady, and the dominant effect is from inertia forces [5].…”

Section: Introductionmentioning

confidence: 99%

“…Saemi et al [5] studied the turbulence dynamics during the pressure-time method by comparing the hydrodynamic forces during the fluid deceleration. Saemi et al [1] applied 2D and 3D models to simulate the water-hammer phenomenon for a straight pipe with different contractions.…”

Section: Introductionmentioning

confidence: 99%

“…In previous numerical studies, such as Refs. [1,5,12,13], the dynamic mesh has been employed to model valve closure. The dynamic mesh may lead to divergence, especially at the end of valve closure, as the generated mesh may have lower quality.…”

Section: Introductionmentioning

confidence: 99%

“…The numerical result is validated with experimental data from Ref. [5] and the pressure-time method is applied to the data. The flow rate is estimated with 0.15% error which shows the possibility of using CFD as an accurate tool to study the pressure-time method.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Numerical investigation of the pressure-time method

Kalantar

Jonsson

Dunca

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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The flow rate is a challenging hydrodynamic parameter to measure in order to determine turbine efficiency. The pressure-time method is a cost-effective alternative to estimate the flow rate. Its principle is based on the transformation of momentum into pressure during the deceleration of the liquid mass. Numerical simulations give valuable information to develop the method. One of the challenges in the numerical study of the pressure-time method is modelling the valve movement. In previous numerical studies, the dynamic mesh has been used for valve closure modelling. The dynamic mesh may lead to divergence, and re-meshing makes this method more time-consuming. In this paper, the valve closure is modelled considering immersed solid method. The results’ sensitivity is studied by different time-step, grid, and boundary conditions at the inlet. It is shown that the result is independent of the time-step size smaller than 0.1 ms. Furthermore, it is observed that only the opening boundary condition at the inlet can predict the oscillation of variables during water hammer phenomenon. Then, the numerical results are validated with experimental data. Finally, the pressure-time method is applied to the data, and the flow rate is estimated.

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Section: Test Casementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical investigation of the pressure-time method

Kalantar

Jonsson

Dunca

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

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Extending the pressure-time method to bend using 3D-CFD

Neyestanaki,

Dunca,

Jonsson

et al. 2024

Flow Measurement and Instrumentation

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Extending the Pressure-Time Method to Pipe With Variable Cross-Section With Three-Dimensional Numerical Simulations

Neyestanaki,

Dunca,

Jonsson

et al. 2023

Journal of Fluids Engineering

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The flow rate in hydraulic turbines can be measured using the pressure-time method specified by the IEC 60041 standard. This method assumes a 1-dimensional flow (1D) and is limited to straight pipes with a uniform cross-section and specific restrictions on length (L>10 m) and velocity (U.L>50 m2s-1). However, in low-head hydropower plants, the intake typically has a variable cross-section and small length, making it challenging to use this method. This paper presents the development of a methodology that extends the applicability of the pressure-time method for variable cross-sections by using three-dimensional computational fluid dynamics (3D CFD). A combination of 3D CFD and 1D pressure-time methods is employed iteratively to estimate the kinetic energy correction factor. The obtained time-dependent values are then used in the 1D pressure-time method to calculate the flow rate. The new methodology is applied with experiments performed on a test rig with a reducer. The obtained results illustrate the significantly different kinetic energy correction factor obtained than those obtained using constant or quasi-steady assumptions. The proposed methodology changes the mean deviation compared to the reference flow meter from -0.83% (underestimation of flow rate) to ±0.1%, increasing the method's accuracy.

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Evaluation of transient effects in the pressure-time method

Cited by 6 publications

References 20 publications

Numerical investigation of the pressure-time method

Numerical investigation of the pressure-time method

Extending the pressure-time method to bend using 3D-CFD

Extending the Pressure-Time Method to Pipe With Variable Cross-Section With Three-Dimensional Numerical Simulations

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