Identification of fluid flow regimes in narrow cracks

Bagshaw, N.M.; Beck, S.B.M.; Yates, J. R.

doi:10.1243/0954406001523542

Cited by 15 publications

(5 citation statements)

References 10 publications

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“…This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. the majority of research has focused on large cracks with applications in the power industry, some work has been done on narrow cracks, such as those found in pressurized gas cylinders [11][12][13]. A model of laminar flow performed well for cracks when the grain size is smaller than the crack width, while for small crack widths, modeling the turns and bends due to material roughness is more accurate [11].…”

Section: Lukas Michiels* Marcus Geimermentioning

confidence: 99%

“…A model of laminar flow performed well for cracks when the grain size is smaller than the crack width, while for small crack widths, modeling the turns and bends due to material roughness is more accurate [11]. Bagshaw et al used a simplified computational fluid dynamics (CFD) model to simulate flow rates in narrow cracks smaller than three times the magnitude of the surface roughness [12].…”

Section: Lukas Michiels* Marcus Geimermentioning

confidence: 99%

“…Bagshaw et al. used a simplified computational fluid dynamics (CFD) model to simulate flow rates in narrow cracks smaller than three times the magnitude of the surface roughness 12.…”

Section: Introductionmentioning

confidence: 99%

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Influence of High Pressure Drop Rates on Fatigue Crack Growth

Michiels

Geimer

2022

Chem Eng & Technol

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Hydraulic components in mobile machines are subjected to varying conditions and loads, which limit their lifetime. In particular, high pressure drop rates are suspected to increase fatigue crack growth rates. Existing studies on the fluidstructure interaction inside fatigue cracks during fast pressure drops do not explain increased crack growth in hydraulic systems. A laminar flow model was developed to simulate the fluid flow inside a crack under periodic pressure loads. The viscosity restrained the oil inside the crack, and the mechanical resistance of the closing crack led to a high pressure increase. Knowledge of the pressure profiles inside fatigue cracks helps to estimate the effective fatigue damage during transient loads.

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Section: Lukas Michiels* Marcus Geimermentioning

confidence: 99%

Section: Lukas Michiels* Marcus Geimermentioning

confidence: 99%

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Influence of High Pressure Drop Rates on Fatigue Crack Growth

Michiels

Geimer

2022

Chem Eng & Technol

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“…Much research has developed in this area, from studies of coolant leak rates through crack opening areas 18 to the effect of crack opening displacement by pressure loads 19,20 . Calculation of crack opening area is the topic of many literatures, 8,21–25 in which fracture analysis of both straight and elbow pipes were carried out for crack configurations of through‐wall circumferential and axial crack, respectively.…”

Section: Crack Opening Area and Fluid Leakagementioning

confidence: 99%

A probabilistic simulation of fluid leakage in multiple cracks situation

Xie

2002

Fatigue Fract Eng Mat Struct

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In pressure vessels and piping the leak‐before‐break (LBB) assessment method is employed to avoid any catastrophic failure prior to a detectable leakage. One of the most important parameter, the leak rate, is investigated in the present paper by means of the Monte Carlo method. A brief review is carried out with emphasis on aspects such as crack growth, crack size with detectable leakage, crack opening area and leak rate. Issues concerning the property and behaviour of multiple cracks are also covered along with a review of the characteristics of leak rate through distributed multiple cracks using a statistical simulation method. The simulation results show that the effect of multiple cracks is quite significant to the LBB concept. Both the relationship between leak rate and crack length (or time) and the statistical characteristics of the leak rate are considerably different for different initial crack conditions.

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“…based on experiments performed by Bagshaw et al [98] In these experiments, the flow of air through narrow artificial crack was observed, and found to approach the flow pattern in Figure 3-6 (b) when the crack width was about twice the roughness amplitude.…”

Section: Evaluation Of Pressure Drop and Flow Rate Of Leaking Argon Tmentioning

confidence: 91%

Study of Joule-Thomson cooling effect due to leakage in compressed gas pressure vessels

Ai¹

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The reliability of pressure vessels in Compressed Natural Gas (CNG) ship is very important because there is very high pressure inside the CNG container (up to 250 bar). A key way to maintaining the integrity of pressure vessels is the principle of Leak-Before-Failure (LBF). However, the temperature of leaking CNG will drop due to Joule-Thomson cooling effect when CNG passes through the crack. The localized cooling effect on the steel plates may affect the ductile to brittle transition failure. Hitherto, the LBF is applied to piping system without considering the temperature change of steel material caused by Joule-Thomson cooling effect. Simulation and experiments thus are desirable to verify the effect in a narrow leaking crack on pressure vessel. By this means, the application of LBF may need to be corrected. The narrow leaking crack can be considered to comprise many short and equivalent parts along the through-wall direction. Each part can be considered as a small throttling type nozzle. An iterative calculation program in MATLAB has been developed in this thesis. Due to the similarity on Joule-Thomson effect, argon is chosen as a substitute for CNG with safety in mind. The program is developed to calculate the pressure, velocity, density, temperature, viscosity, thermal conductivity and heat transfer coefficient of leaking argon through the crack by considering the Joule-Thomson effect. The calculated results of temperature, pressure and heat transfer coefficient of argon along the crack depth are used as boundary conditions in COMSOL FEA program for the heat transfer and thermal stress simulation. In MATLAB iterative calculations, the initial argon pressure inside the pressure vessel is the maximum pressure of 91 bar during test. The initial temperature is room temperature of 30 o C. Solutions of pressure, velocity and density of leaking argon of each small space inside the crack are firstly obtained after inputting the crack dimensions and roughness parameters. The pressure of leaking Argon drops from 91 bar at the entrance of the crack to 9.5 bar at the exit of the crack. The velocity of leaking Argon through the crack does not change much. The density of leaking Argon drops from 150.7 kg/m 3 at the entrance of the crack to 16.8 kg/m 3 at the exit of the crack. Then the temperature of leaking argon inside the crack is calculated. The temperature of leaking Argon decreases from 30 o C at the entrance of the crack to 0.04 o C at the exit of the crack.

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Identification of fluid flow regimes in narrow cracks

Cited by 15 publications

References 10 publications

Influence of High Pressure Drop Rates on Fatigue Crack Growth

Influence of High Pressure Drop Rates on Fatigue Crack Growth

A probabilistic simulation of fluid leakage in multiple cracks situation

Study of Joule-Thomson cooling effect due to leakage in compressed gas pressure vessels

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