Computational Fluid Dynamics Modeling of Single Isothermal and Non-Isothermal Impinging Jets in a Scaled-Down High-Temperature Gas-Cooled Reactor Facility

Alwafi, Anas; Alshehri, Salman M.; zahrani, Salman Al

doi:10.3390/pr11010046

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…To capture the turbulent characteristics of the jet core more accurately, the mesh was refined in the core region. The numerical simulations were conducted using the Finite Volume Method and the ANSYS Fluent 2020 R2 software [34,35], and the calculations were performed using a double-precision steady-state solver. Based on the information provided by NASA [32], a steady-state solution was calculated using the SA turbulence model.…”

Section: Computational Settingsmentioning

confidence: 99%

Calibration of Turbulent Model Constants Based on Experimental Data Assimilation: Numerical Prediction of Subsonic Jet Flow Characteristics

Yuan

Gao

et al. 2023

Sustainability

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Experimental measurements and numerical simulations are two primary methods for studying turbulence. However, these methods often struggle to balance the accuracy and breadth of results. In order to accurately predict the flow characteristics of subsonic jet exhaust and provide a research foundation for the runway crossing operation after the takeoff point, this study utilizes the ensemble Kalman filter algorithm to recalibrate the SA turbulence model constants by integrating NASA’s experimental particle image velocimetry (PIV) data with a sample library generated using Latin hypercube sampling to obtain corresponding flow field calculations. The modified model constants effectively improve the prediction of jet flow characteristics, reducing the spatially averaged relative error along the horizontal axis behind the nozzle from 13.04% to 4.6%. This study focuses on enhancing the accuracy of numerical predictions for subsonic jet flows via the adjustment of turbulence model constants. The recalibrated model constants are then validated to improve the prediction of jet flows under various conditions. The findings have important implications for acquiring high-fidelity data on rear engine jet flows after takeoff, enabling precise determination of safety separation distances, and enhancing the operational efficiency of airports.

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Section: Computational Settingsmentioning

confidence: 99%

Calibration of Turbulent Model Constants Based on Experimental Data Assimilation: Numerical Prediction of Subsonic Jet Flow Characteristics

Yuan

Gao

et al. 2023

Sustainability

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“…Computational fluid dynamics (CFD) simulation has been widely used in the study of jet flow, and numerical simulation provides theoretical support to facilitate engineering applications. The k-ε turbulence models made more contributions to studying the largescale vortices caused the jet flow [11][12][13]. However, the changes in small-scale vortices with time cannot be studied in depth.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Curvature Radius on Single-Droplet Dynamic Characteristics within a Concave-Wall Jet

Gong,

Jian,

Zhang

et al. 2024

Processes

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The centrifugal force field in a hydrocyclone was affected by the concave-wall curvature radius R0, and the mechanism underlying droplet deformation was closely related to the mass transfer efficiency. Numerical simulation and experimental data were collected to reveal the deformation characteristics and mechanism of a single droplet crossing concave-wall jet. Normalized interfacial energy γ and stretching performance were provided to investigate the droplet deformation process. The results showed that the droplet was stretched along the streamwise direction and shrank along the spanwise direction in the concave-wall jet. The droplet interfacial energy and deformation were the largest when the droplet crossed the jet boundary at t = 0.20 s. The maximum γ value increased with the increase in R0 by 57.3% to 71.4%, and the distance between the droplet and concave wall increased with R0. The Q-criterion was exported to show the increase in the vortex strength with the decrease in R0 at the jet boundary. The pressure distribution inside the droplet showed that the pressure decreased as R0 increased, while the pressure difference increased along the streamwise and wall-normal directions. This study suggested that the droplet breakup was more difficult for a smaller R0, which was beneficial for liquid–liquid heterogeneous separation.

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Validation of a Human Upper Airway Computational Fluid Dynamics Model for Turbulent Mixing

Kacinski,

Strasser,

Leonard

et al. 2023

Journal of Fluids Engineering

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Validation of a CFD model used to simulate turbulent exchange in an anatomically detailed human upper airway with realistic breathing states is provided. Proper model validation is vital in confirming that temporal mixing and species distribution are accurate, therefore making the model useful in generalized turbulent mixing studies of the upper airway. Numerous levels of refinement were tested for timestep and mesh independence. Higher and lower rigor groups of modeling methodologies involved spatial discretization schemes, gradient reconstruction methods, transient formulations, and turbulence frameworks. A dual mesh independence study revealed that the rate of approach to mesh independence is a function of computational rigor and that multiple mesh independence studies should be carried out in parallel. The final validated model consisted of the finest mesh used in this study (8 million cells), a timestep equating to 4000 timesteps per breath cycle, and higher rigor modeling methodologies. While its results were within the acceptable deviation from the experimental data, it was not as close as the model that utilized the coarsest mesh (~2 million cells), the fewest timesteps per breath cycle (128 timesteps per breath cycle), and lower rigor methodologies. Though the latter model was closer to the experimental data, it was proven to not be numerically independent, highlighting the importance of utilizing a myriad of metrics to prove numerical independence. Restricting independence studies to only using metrics from experimental comparisons is insufficient for proper validation.

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Computational Fluid Dynamics Modeling of Single Isothermal and Non-Isothermal Impinging Jets in a Scaled-Down High-Temperature Gas-Cooled Reactor Facility

Cited by 3 publications

References 27 publications

Calibration of Turbulent Model Constants Based on Experimental Data Assimilation: Numerical Prediction of Subsonic Jet Flow Characteristics

Calibration of Turbulent Model Constants Based on Experimental Data Assimilation: Numerical Prediction of Subsonic Jet Flow Characteristics

Effect of the Curvature Radius on Single-Droplet Dynamic Characteristics within a Concave-Wall Jet

Validation of a Human Upper Airway Computational Fluid Dynamics Model for Turbulent Mixing

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