Comparison of formulas for drag coefficient and settling velocity of spherical particles

In oil and gas pipeline operations, the gas, oil, and water phases simultaneously move through pipe systems. The mixture cools as it flows through subsea pipelines, and forms a hydrate formation region, where the hydrate crystals start to grow and may eventually block the pipeline. The potential of pipe blockage due to hydrate formation is one of the most significant flow-assurance problems in deep-water subsea operations. Due to the catastrophic safety and economic implications of hydrate blockage, it is important to accurately predict the simultaneous flow of gas, water, and hydrate particles in flowlines. Currently, there are few or no studies that account for the simultaneous effects of hydrate growth and heat transfer on flow characteristics within pipelines.This thesis presents new and more accurate predictive models of multiphase flows in undersea pipelines to describe the simultaneous flow of gas, water, and hydrate particles

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“…Yuen and Chen (1976) reported that the drag coefficient for small particles is close to that for solid spheres. Cheng's (2009) …”

Section: Momentum Equationmentioning

confidence: 99%

Volume Averaging of Multiphase Flows With Hydrate Formation in Subsea Pipelines

Torbati

Naterer

Odukoya

2015

Volume 5B: Pipeline and Riser Technology

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“…Therefore, if the history force would be neglected for a swirling flow, the choice of the drag factor is not that important as long as it takes into account non-Stokesian effects sufficiently. The accuracy of the expression proposed by Cheng (2009) is reported to be higher than that of Schiller & Naumann (1993) [10]. Moreover, it does not have a singularity in its first derivative.…”

Section: Fluid and Particle Propertiesmentioning

confidence: 83%

“…However, in 2003 Brown & Lawler corrected this data for wall effects in order to obtain a more accurate error estimation [6]. Cheng's correlation, obtained using this corrected data, is shown to have higher accuracy than other similar expressions with respect to the data corrected for wall effects [6,10]. The resulting drag curves of the correlations are presented in figure 3.3.…”

Section: Drag Coefficient and Drag Factormentioning

confidence: 98%

“…The resulting drag curves of the correlations are presented in figure 3.3. The drag correlation by Cheng [10] smoothly transitions from the drag in the Stokes regime to the drag in the Newton regime. The drag correlation by Schiller & Naumann [35] results in values for the drag coefficient for Reynolds numbers up to the Newton regime very similar to Cheng's expression.…”

Section: Drag Coefficient and Drag Factormentioning

confidence: 99%

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Dispersed droplet dynamics during produced water treatment in oil industry

Eijkeren¹

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For Lagrangian particle tracking applied to swirling flow produced water treatment the influence of the history force is investigated. In the expression for the history force an existing Reynolds number dependent kernel is adapted and validated for a range of experimental data for settling spheres. This kernel is used during the numerical simulation of oil-droplets in an idealized flow field as model for flow fields observed in swirling flow separators. It is shown that the history force should not be neglected for the motion of particles in such flows. However, for this specific type of flow it is shown that the contribution of the history force might be approximated as a drag-like expression.Subsequently, an efficient collision detection mechanism is developed to obtain collision detection with a work-load of O (N p ln N p ). The scheme is validated for settling spheres and applied to the swirling flow field used during the investigation of the influence of the history force.Finally, two approaches for the lattice Boltzmann method, taking into account the equation of state for water, are presented. One approach utilizing a pressure corrected BGK approximation, the other a dense gas BBGKY approximation. A novel approach is used to obtain the macroscopic quantities and boundary conditions. It is shown that for modeling the flow of water around a particle an ideal-gas lattice Boltzmann method to simulate water is not capable of capturing all relevant details. However, modeling the flow with both proposed approaches, which take the equation of state into account, lead to similar results.v Samenvatting Dit onderzoek gaat in op de kracht op een deeltje nodig voor een Lagrangiaanse methode voor het voorspellen van deeltjesbanen, toegepast op het behandelen van geproduceerd water met oliedeeltjes met behulp van een roterende stroming. De bijdrage in de kracht gerelateerd aan de historie van de beweging van het deeltje wordt in detail behandeld. Een bestaande kernel, afhankelijk van het Reynoldsgetal, voor de integraal in deze bijdrage in de kracht is aangepast en gevalideerd aan de hand van experimentele data voor sedimenterende bollen uit de literatuur. Deze aangepaste kernel is toegepast bij het numerieke voorspellen van banen van oliedruppels in een geïdealiseerd stromingsveld, kenmerkend voor roterende-stromingsscheiders. Dit onderzoek laat zien dat de historiekracht niet verwaarloosd kan worden bij het berekenen van de baan van deeltjes in zulke stromingen. Voor een specifiek geval wordt getoond dat deze kracht benaderd kan worden met een uitdrukking die lijkt op die van de weerstandskracht.Vervolgens gaat dit onderzoek in op een efficiënte methode om botsingen te detecteren in dergelijke numerieke berekeningen. De benodigde rekentijd van deze methode varieert als O (N p ln N p ). De methode is eerst gevalideerd voor sedimenterende bollen. Vervolgens is de methode toegepast en onderzocht in het bovengenoemde kenmerkende stromingsveld in roterende stromingsscheiders.Tenslotte worden twee methodes gepresent...

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“…Cheng (13) propôs uma fórmula geral para o coeficiente de arraste aplicável para todos os casos onde Re < 2 x10 5 . Além disto, o autor comparou outras fórmulas apresentadas por outros autores.…”

Section: Mecanismos Da Decantação De Partículas Sólidas Em Meio Líquidounclassified

Formação da macrossegregação de carbono no silício durante a solidificação direcional ou decantação de carbonetos.

Ribeiro¹

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Comparison of formulas for drag coefficient and settling velocity of spherical particles

Cited by 287 publications

References 9 publications

Volume Averaging of Multiphase Flows With Hydrate Formation in Subsea Pipelines

Volume Averaging of Multiphase Flows With Hydrate Formation in Subsea Pipelines

Dispersed droplet dynamics during produced water treatment in oil industry

Formação da macrossegregação de carbono no silício durante a solidificação direcional ou decantação de carbonetos.

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