Study of two phase thermal stratification in cylindrical vessels: CFD simulations and PIV measurements

Gandhi, Mayurkumar S.; Joshi, Jyeshtharaj B.; Vijayan, P.K.

doi:10.1016/j.ces.2013.04.051

Cited by 21 publications

(7 citation statements)

References 57 publications

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“…Previous studies demonstrated that natural convection boundary layer in enclosures turns from laminar to turbulent regime faster than natural convection boundary layer for vertical semi‐infinite walls . As a matter of fact, in several works dealing with modeling studies of vessels exposed to external heat sources, turbulent natural convention flow was predicted . Therefore, a turbulence model was used since the start of the CFD simulation.…”

Section: Modelmentioning

confidence: 99%

“…Several studies afford the general theme of heat‐induced liquid stratification. Recent publications showed the results obtained modeling thermal stratification in systems in which water is used, such as electronics and photovoltaic cooling equipment, thermosiphon and hydrosiphon heat exchangers, solar‐thermal heat absorbers, and passive decay heat removal systems . Thermal stratification may also affect nuclear reactors water cooling systems and cryogenic storage systems .…”

Section: Introductionmentioning

confidence: 99%

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CFD modeling of LPG vessels under fire exposure conditions

et al. 2014

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Fire exposure of tanks used for the storage and transportation of liquefied gases under pressure may cause complex heat- and mass-transfer phenomena that may contribute to compromise the integrity of the vessels in accident scenarios. Heat transfer through vessel lading results in the heat-up of the internal fluid and the increase of vessel internal pressure. However, local temperature gradients in the liquid phase cause liquid stratification phenomena that result in a more rapid vaporization and pressure build-up in the liquid phase. These fundamental phenomena were analyzed by a computational fluid dynamic model. The model was specifically focused on the early steps of vessel heat-up, when liquid stratification plays a relevant role in determining the vessel internal pressure. A two-dimensional transient simulation was set up using ANSYS FLUENT in order to predict the evolution of the liquid and vapor phases during the tank heat up. The model was validated against large scale experimental data available for liquefied petroleum gas vessels exposed to hydrocarbon fires, and was applied to case studies derived from recent accidental events in order to assess the expected time of pressure build-up in different fire scenarios

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Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CFD modeling of LPG vessels under fire exposure conditions

et al. 2014

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“…Eulerian-Eulerian two-phase model is the most complex of the two-phase models; however, it is more accurate than other models because it solves a set of n two-phase differential equations for each phase [29], where the computational effort depends strongly on the number of transport equations which need to be solved. Eulerian-Eulerian two-phase models have been used to simulate two-phase flows in different geometries: Hwang and Pal [30], Roul and Sahoo [29], Delnoij et al [31], Rampure et al [32] Gandhi et al [33], Dasari and Goshika [34], Walvekar et al [35], Parvareh et al [36] and Ekambara et al [13].…”

Section: Simulation Approachmentioning

confidence: 99%

Two-Phase Flow Development of R134a in a Horizontal Pipe: Computational Investigation

Mahmood¹,

Saleh²,

Musa³

et al. 2021

IJHT

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To improve the performance of vapor compression refrigeration systems that use vertical gravitational flash tank separators, the liquid separation efficiency of the vertical gravitational flash tank separator requires to be approved. To approach this improvement, the two-phase flow development and its behavior after the expansion device need to be investigated and predicted. For thus, this paper presents a three-dimensional computational investigation of the two-phase flow development of R134a after the expansion device in a horizontal pipe. Computational Fluid Dynamic (CFD) was used to predict the two-phase development and its behavior in the horizontal pipe. ANSYS 16.2 program was used to generates the geometry of the three-dimensional horizontal pipe of 2 meters long and 25 mm inner diameter. The hexahedral mesh was generated and it is assessed to obtain the optimum mesh size and number. Eulerian-Eulerian two-phase model was used with k-ɛ turbulence model. R134a was used as a working fluid in the horizontal pipe utilizing four different inlet diameters: 12, 12.5, 25, and 50.0 mm. Mass flux and vapor quality have been changed from 288 to 447 kg/m2.s and from 10 to 20% respectively. Results were validated against experimental results from the literature and revealed that the separation region length is affected by the initial phase velocities, inlet vapor quality, and inlet tube diameter. An empirical correlation to predict the expansion region length is proposed as a function of Froude, Webber, and Lockhart-Martinelli numbers.

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“…Distributed parameters models were applied to the assessment of similar problems, e.g. to the analysis of the heat-up of water in pressurized tanks (Gandhi et al (2013), Han et al (2009)), of asphalt in cylindrical tanks (Costa et al (2013)) or cryogenic liquids (Das et al (2004), Ren et al (2013), Roh et al (2013), Wang et al (2013)) exposed to external heat sources. Some studies were devoted to the analysis of small scale tanks containing pressurized hydrogen gas exposed to localized fires, supported by specific experiments (e.g., Zheng et al 2012 Another key issue that may be investigated through distributed parameters code is the structural response of equipment when exposed to fire.…”

Section: Introductionmentioning

confidence: 99%

Coupling of integral methods and CFD for modeling complex industrial accidents

Rum

Landucci

Galletti

2018

Journal of Loss Prevention in the Process Industries

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Safety enhancement of operations in the chemical and petrochemical industry requires for advances in the tools aimed at supporting risk estimation and evaluation. In conventional risk studies, consequence assessment is carried out through simplified tools and conservative assumptions, often resulting in overestimation of accident severity and worst-case scenarios. Computational Fluid Dynamics (CFD) may overcome the limitation of simplified approaches supporting the study of the dynamic evolution of accidental scenarios and, eventually, the consequences analysis of major accidents. However, the complexity of the problem makes the simulations too computationally demanding; hence an interesting approach is to couple simplified tools based on integral models and CFD. This work is aimed at modeling a safety critical scenario, i.e. domino effect triggered by fire. An integral model is adopted to reproduce a large-scale pool fire, thus simulating the radiative heat received by an exposed pressurized vessel. The behavior of the latter is then modeled through CFD, to investigate the heat-up process and the consequent pressure build up. Potential benefits and limitations of coupling distributed and integral models to support consequence assessment studies are discussed

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Study of two phase thermal stratification in cylindrical vessels: CFD simulations and PIV measurements

Cited by 21 publications

References 57 publications

CFD modeling of LPG vessels under fire exposure conditions

CFD modeling of LPG vessels under fire exposure conditions

Two-Phase Flow Development of R134a in a Horizontal Pipe: Computational Investigation

Coupling of integral methods and CFD for modeling complex industrial accidents

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