Numerical and experimental investigations of water hammers in nuclear industry

Messahel, Ramzi; Cohen, Bernard; Moatamedi, Mojtaba; Boudlal, Abdellatif; Souli, M’hamed; Aquelet, Nicolas

doi:10.1260/1750-9548.9.1.21

Cited by 4 publications

(2 citation statements)

References 16 publications

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“…A pressure undershoots increases with increasing depressurization rates. Alamgir and Lienhard [5] conducted flashing experiments on hot-water. They reported that the pressure undershoot depends on the rate of depressurization and initial temperature except for the case below the depressurization rate of 400MPa/s.…”

Section: Pressure Undershoot and Pressure Recoverymentioning

confidence: 99%

“…Then, the liquid starts changing its phase to resolve the non-equilibrium state. This phenomenon of explosive vaporization is called the flashing phenomenon and is of special interest in engineering for the designs of safety systems involving high-pressure and/or high-temperature liquids, particularly in connection with a loss-of-coolant accident (LOCA) in nuclear reactors [1][2][3][4][5] and LNG storage tanks [6]. While many works concerning with the flashing phenomenon have focused on hot water in a high rate of depressurization (over 100MPa/s), flashing of fluids other than water and under slow rate of depressurization have not been investigated sufficiently.…”

Section: Introductionmentioning

confidence: 99%

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Phenomena of Liquid Nitrogen Flashing under Rapid Depressurizations

2022

IJM

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Flashing Experiment of liquid nitrogen in a pressure vessel was conducted under rapid depressurization rate. Observations of the explosive boiling behavior caused by quick opening of a electro-magnetic valve were undertaken by using a video camera. Pressure and temperature changes in the vessel were measured. Depressurization rates in these experiments fell in the range from 0.01 to 4.0MPa/s. Experimental results showed that the initial temperature distributions and depressurization rates have more intrinsic influence on these flashing phenomena. Relationship between pressure undershoot and depressurization rate was obtained. The rate of pressure recovery was found to increase with the rate of depressurization, which also resulted in the increase of the increment of pressure recovery. The empirical equation proposed by Alamgir and Lienhard was applied to predict the recovery pressure of the flashing of liquid nitrogen. To obtain more precise prediction of the pressure recovery, another factor such as an orifice diameter that affects the discharge condition of the recovery pressure.

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Section: Pressure Undershoot and Pressure Recoverymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phenomena of Liquid Nitrogen Flashing under Rapid Depressurizations

2022

IJM

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Experimental and Numerical Study of Pressure in a Shock Tube

Khawaja

Messahel

Ewan

et al. 2016

Journal of Pressure Vessel Technology

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This paper presents the behavior of pressure in an air–water shock tube. In this work, high-pressure air (at 100 bar) interacts with water (at 1 atm ∼ 1 bar) through an orifice in a 100 mm constant diameter tube. The experiments are repeated with three different orifice plate diameters of 4, 8, and 15 mm. The variation of pressure during the transient stage is recorded in these experiments and it is found that with increasing orifice diameter, the amplitude of the pressure increases linearly with time when all other conditions are unchanged. The same phenomenon is simulated using the ls-dyna® software using an arbitrary Lagrangian Eulerian (ALE) method to solve the problem numerically. Simulations are made with a range of orifice diameters. The experimental results confirm the validity of the simulations algorithm. The simulations also demonstrated that the pressure behaves linearly with orifice diameter only when orifice diameter is less than 15% of the tube diameter.

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Investigation of Blood Flow Modeling in Artery Using ALE Formulation

Souli

Al-Bahkali

Thamer

et al. 2017

Int. J. Comput. Methods

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The aim of the paper is to use Arbitrary Lagrangian Eulerian (ALE) formulation for fluid–structure interaction for modeling blood flow in artery. Predicting blood flow and its effects on arteries requires simulation of fluid–structure coupling with deformable mesh. For fluid simulation velocity–pressure formulation is used, we present the algorithm which allows to compute fluid velocity and pressure using explicit time integration. This method has been applied successfully for several applications including sloshing tank analysis. For the structure shell type elements with five points integration through the thickness to accurately represent bending effects, are modeled. Since the structure is deformable, to prevent high mesh distortion an elasticity material model for the mesh is used for mesh deformation. For fluid–structure coupling, explicit contact algorithm based on penalty method. Such a model can be used to study the profile of the flow and pressure waves as they propagate along the arteries. In the paper, the onset of a pressure pulse was simulated at the entrance of a three dimension straight artery blood vessel and the resulting dynamic response in the form of a propagating pulse wave through the wall was analyzed and compared. Good agreement was found between the numerical results and the theoretical description of an idealized artery. Work has also been done on implementing the material constitutive models specific for vascular applications.

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Numerical and experimental investigations of water hammers in nuclear industry

Cited by 4 publications

References 16 publications

Phenomena of Liquid Nitrogen Flashing under Rapid Depressurizations

Phenomena of Liquid Nitrogen Flashing under Rapid Depressurizations

Experimental and Numerical Study of Pressure in a Shock Tube

Investigation of Blood Flow Modeling in Artery Using ALE Formulation

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