Resistance Coefficients for Accelerated and Decelerated Flows Through Smooth Tubes and Orifices

Daily, John W.; Hankey, W. L.; Olive, R. W.; Jordaan, Jan M.

doi:10.1115/1.4013923

Cited by 47 publications

(8 citation statements)

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“…The steady friction equation based on the Darcy-Weisbach friction relationship is expressed as On the other hand, many authors have established different unsteady friction models. Daily et al 19 considered the instantaneous acceleration as a calculation stress in 1956. Zielke 20 presented an unsteady friction model for laminar flow that utilizes past weighted velocity.…”

Section: Model Of the Long Hydraulic Pipelinementioning

confidence: 99%

“…Many studies have shown that only considering the steady friction loss in the pipeline can only accurately calculate the pressure value of the first wave peak, while the subsequent pressure evaluation is inaccurate. [18][19] The charging of subsea accumulators is a long-term process, so it is not enough to evaluate the first peak of pressure propagation, so the unsteady frictional resistance in the pipeline must be considered.…”

Section: Introductionmentioning

confidence: 99%

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Transient mathematical prediction and experimental verification of the charging characteristics of subsea accumulators

Liu

Tang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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This study is focused on the charging characteristics of the subsea accumulators used to provide power for safety on a subsea well. The charging time and storage volume are strictly limited according to API specification for a subsea accumulator system. Long hydraulic lines must be used to cope with the depth of seawater, which will significantly increase the charging time and cause a large pressure drop. In addition, the pressure in hydraulic pump and subsea accumulators used also varies with charging. A transient flow will occur during the charging of the system. In this paper, a systematic transient mathematical model (STMM) of the subsea accumulator charge system is established. The STMM includes three main parts: the air driven liquid pump, the long hydraulic pipeline, and the subsea accumulator. A double-coefficient unsteady friction model based on instantaneous acceleration is applied in the long pipeline model. The Redlich–Kwong real gas state equation is used to calculate the gas in the accumulator. A series of charging experiments for two rated working pressure of 10,000 psi and 15,000 psi on the ground were carried out. The results of the experiment showed very consistently with those of the STMM. The liquid pressure in the accumulator is divided into three stages during charging: rapidly increasing stage, slowly increasing stage, and maintaining constant stage. Moreover, an engineering proposal was presented to reduce the design pressure requirements of the system. Furthermore, the charging time will increase significantly as the length of the pipe increases, but decreases as the inner diameter of the pipe increases. The paper outlines a direction for the design theory and engineering practice of the subsea accumulator charge system.

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Section: Model Of the Long Hydraulic Pipelinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient mathematical prediction and experimental verification of the charging characteristics of subsea accumulators

Liu

Tang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…The model presented by Brunone et al 2000 is the most commonly used in conventional transient analyses, However, it does not fit the Lagrangian approach for transients modeling. Consequently, in addition to the Darcy-Weisbach equation, the Daily (1955) empirical correction to the wall shear stress model was adopted here to compute the head-loss and shear stresses along the pipelines. The wall shear stress is expressed as:…”

Section: Unsteady Friction Attenuationmentioning

confidence: 99%

Unsteady Friction Modeling Technique for Lagrangian Approaches in Transient Simulations

Zeidan,

Ostfeld

2022

Proceedings - 2nd International Join Conference on Water Distribution System Analysis (WDSA)& Computing and Control in the

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This study tackles the problem of simulating the head damping effect in transient flows when modeled in the Lagrangian approach rather than Eulerian. The Lagrangian approach normally requires orders of magnitude fewer calculations, which allows very large systems to be solved in an expeditious manner, and it has the additional advantage of using a simple physical model as the basis for its development. Moreover, since it is continuous in both time and space, the method is less sensitive to the structure of the network and the length of the simulation process, resulting in improved computational efficiency. Nevertheless, most recent studies used an Eulerian approach when simulating the systems transient response (e.g., method of characteristics), thus focused on developing and improving different computational routines for modeling and simulating unsteady friction models that are better fixated for Eulerian methods and are not suited for Lagrangian ones. One-dimensional methods of representing unsteady contributions to skin friction based on instantaneous acceleration have a long track record (e.g., Daily et al. 1956, Carstens and Roller 1959). And it is still the most popular method in software used for practical simulations, despite it cannot accurately depict the system's transient responses without additional calibrations and tunings. However, the more accurate models (e.g., Brunone 2000) are not suited for the Lagrangian approach. The lack of a mesh structure in the Lagrangian approach makes it challenging to consider the convective acceleration terms in addition to the local acceleration. Therefore, there is a need for a more accurate friction model that is suited for Lagrangian methods without compromising their performance. Unfortunately, such a model is yet to be published in the literature. This study presents a new friction modeling technique that compensates for both the local and convective acceleration terms for the Lagrangian transient modeling approach, without compromising the computational time. Additionally, fixating only on the Eulerian approach for transient modeling and undermining the Lagrangian based models is concerning since it can provide different perspectives for developing novel solutions and tools that take advantage of transient events.

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“…This type of 1D unsteady friction model is based on the instantaneous acceleration of the fluid (Brunone et al 1991). Daily et al (1956) developed a model in which the unsteady friction is dependent on instantaneous mean flow velocity and instantaneous local acceleration. Carstens & Roller (1959) presented the influence of instantaneous mean flow velocity and instantaneous local acceleration on friction terms.…”

Section: Introductionmentioning

confidence: 99%

3D CFD simulation and analysis of transient flow in a water pipeline

Cao

Zhou

et al. 2022

Journal of Water Supply: Research and Technology-Aqua

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A three-dimensional (3D) computational fluid dynamics (CFD) approach is developed to elaborate the water-hammer pipe flow and 3D detailed dynamic characteristics of a closing ball valve. The proposed CFD approach considers the water compressibility and the viscous sublayer, which are sometimes neglected in previous studies. Comparisons of the CFD results, the measured pressures and the one-dimensional results, demonstrate that the current 3D CFD approach better reproduces the experimental pressure oscillations while helping to visualize the associated physical processes and to further explore the 3D transient characteristics. The mean velocity distributions in the radial direction significantly change as the pipe transient progresses, which is closely associated with transient shear stress. Mean velocity variations at the valve during the closing process undergo three distinct stages: slight change, then drastic reduction, and finally slowing down. Head loss coefficient and discharge coefficient of the valve change as the valve closing time shortens.

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Resistance Coefficients for Accelerated and Decelerated Flows Through Smooth Tubes and Orifices

Cited by 47 publications

References 0 publications

Transient mathematical prediction and experimental verification of the charging characteristics of subsea accumulators

Transient mathematical prediction and experimental verification of the charging characteristics of subsea accumulators

Unsteady Friction Modeling Technique for Lagrangian Approaches in Transient Simulations

3D CFD simulation and analysis of transient flow in a water pipeline

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