Numerical investigations on the coupling of the one-group interfacial area transport equation and subcooled boiling models for nuclear safety applications

Alali, Abdullah E.; Schöffel, Philipp Josef; Herb, Joachim; Macian, Rafael

doi:10.1016/j.anucene.2018.05.034

Cited by 9 publications

(6 citation statements)

References 39 publications

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“…Nevertheless, the CFD model tends to underestimate void fractions. Alali et al 20 has studied the same problem in OpenFOAM; their results were in the range of previous works.…”

Section: Introductionmentioning

confidence: 59%

Eulerian multiphase study of direct steam generation in parabolic trough with OpenFOAM

Achi

Demagh

2022

Heat Trans

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Direct steam generation (DSG) in parabolic trough solar collectors is a feasible option for economic improvement in solar thermal power generation. Three‐dimensional Eulerian two‐fluid simulations are performed under OpenFOAM to study the turbulent flow in the evaporation section of the parabolic trough receiver and investigate the phase change, and pressure drop of water as a heat transfer fluid. First, the model's validity has been tested by comparing the numerical results of a laboratory scale boiler with the available correlations and semi‐correlations of boiling flows from the literature. Simulations agreed well with Rouhani–Axelsson correlation for horizontal tubes, with a mean relative error of less than 7.1% for all studied cases. However, despite a mean relative error of less than 13.19% compared to the experimental data in the literature, the reported pressure drop factor remains valid; overprediction remains tolerable for most engineering applications. Second, the scaling effect on the mathematical model, from laboratory to commercial‐scale configuration, was tested with experimental data of the DISS test loop in Platforma Solar de Almeria, Spain. The Monte Carlo Ray Tracing method under the Tonatiuh package allowed for obtaining the nonuniform heat flux distribution. Due to the large size of the evaporation section in the DISS loop (eight collectors), each collector is considered independently in the simulations. Thus, simulations follow each other, taking the numerical results of each collector output as input data in the next collector and so on until the last. The numerical results showed an excellent agreement for the void fraction with 3.53% against the Rouhani–Axelsson correlation. Frictional pressure losses are within a 17.06% error of the Friedel correlation, in the range of previous work in the literature, and the heat loss is less than 4.69% error versus experimental correlation.

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“…Nevertheless, the CFD model tends to underestimate void fractions. Alali et al 20 has studied the same problem in OpenFOAM; their results were in the range of previous works.…”

Section: Introductionmentioning

confidence: 59%

Eulerian multiphase study of direct steam generation in parabolic trough with OpenFOAM

Achi

Demagh

2022

Heat Trans

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“…It has been shown [10] that bubble coalescence and break-up can significantly affect the predicted results of two-phase flows within small tubes/channels. A widely used model that accounts for bubble coalescence and break-up is the interfacial area transport equation (IATE) method proposed by Wu et al [50] and further developed by Ishii et al [51].…”

Section: Iate Modelmentioning

confidence: 99%

“…This method treats each phase separately with its own set of governing equations for the conservation of mass, momentum and energy. These conservation equations are usually coupled with empirical closures for the momentum and mass exchange between the liquid and vapour phases, as well as for physical mechanisms such as the heat and mass forces across the interface, thus determining the level of thermal and hydraulic non-equilibrium between the phases [10]. The closures that relate to the boiling heat transfer constitute part of the wall heat flux partitioning model, where the partitioning of the wall heat flux into these physical mechanisms is responsible for the wall boiling heat transfer, are described.…”

Section: Introductionmentioning

confidence: 99%

Validation of the Eulerian–Eulerian Two-Fluid Method and the RPI Wall Partitioning Model Predictions in OpenFOAM with Respect to the Flow Boiling Characteristics within Conventional Tubes and Micro-Channels

Vontas,

Pavarani,

Miché

et al. 2023

Energies

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Flow boiling within conventional, mini and micro-scale channels is encountered in a wide range of engineering applications such as nuclear reactors, steam engines and cooling of electronic devices. Due to the high complexity and importance of the boiling process, several numerical and experimental investigations have been conducted for the better understanding of the underpinned physics and heat transfer characteristics. One of the most widely used numerical approaches that can analyse such phenomena is the Eulerian–Eulerian two-fluid method in conjunction with the RPI model. However, according to the current state-of-the-art methods this modelling approach heavily relies on empirical closure relationships derived for conventional channels, limiting its applicability to mini- and micro-scale channels. The present paper aims to give further insights into the applicability of this modelling approach for non-conventional channels. For this purpose, a numerical investigation utilising the Eulerian–Eulerian two-fluid model and the RPI wall heat flux partitioning model in OpenFOAM 8.0 is conducted. Initially the parameters comprising the empirical closure relationships used in the RPI sub-models are tuned against the DEBORA experiments on conventional channels, through an extensive sensitivity analysis. In the second part of the investigation, numerical simulations against flow boiling experiments within micro-channels are performed, utilising the previously optimised and validated model setup. Furthermore the importance of including a bubble coalescence and break-up sub-model to capture parameters such as the radial velocity profiles, is also illustrated. However, when the optimal model setup, in conventional tubes, is used against micro-channel experiments, the need to develop new correlations from data obtained from mini and micro-scale channel studies, not from experimental data on conventional channels, is revealed.

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“…To calculate the interfacial terms, we also need the bubble/droplet Sauter mean diameter, which is previously used in the literature related to subcooled boiling [28,32,33] and is the default choice to represent a bubble size in OpenFOAM. Nevertheless, due to reasons explained below in detail, we consider the influence of particles' diameters out of this article's scope.…”

Section: Interfacial Termsmentioning

confidence: 99%

Film Boiling Conjugate Heat Transfer during Immersion Quenching

Kamenický

Frank²,

Drikakis

et al. 2022

Energies

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Boiling conjugate heat transfer is an active field of research encountered in several industries, including metallurgy, power generation and electronics. This paper presents a computational fluid dynamics approach capable of accurately modelling the heat transfer and flow phenomena during immersion quenching: a process in which a hot solid is immersed into a liquid, leading to sudden boiling at the solid–liquid interface. The adopted methodology allows us to couple solid and fluid regions with very different physics, using partitioned coupling. The energy equation describes the solid, while the Eulerian two-fluid modelling approach governs the fluid’s behaviour. We focus on a film boiling heat transfer regime, yet also consider natural convection, nucleate and transition boiling. A detailed overview of the methodology is given, including an analytical description of the conjugate heat transfer between all three phases. The latter leads to the derivation of a fluid temperature and Biot number, considering both fluid phases. These are then employed to assess the solver’s behaviour. In comparison with previous research, additional heat transfer regimes, extra interfacial forces and separate energy equations for each fluid phase, including phase change at their interface, are employed. Finally, the validation of the computational approach is conducted against published experimental and numerical results.

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Numerical investigations on the coupling of the one-group interfacial area transport equation and subcooled boiling models for nuclear safety applications

Cited by 9 publications

References 39 publications

Eulerian multiphase study of direct steam generation in parabolic trough with OpenFOAM

Eulerian multiphase study of direct steam generation in parabolic trough with OpenFOAM

Validation of the Eulerian–Eulerian Two-Fluid Method and the RPI Wall Partitioning Model Predictions in OpenFOAM with Respect to the Flow Boiling Characteristics within Conventional Tubes and Micro-Channels

Film Boiling Conjugate Heat Transfer during Immersion Quenching

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