Influence of the Prandtl Number on Wall-to-Fluid Thermal Transfer Rate in a Cubic Cavity

Duarte, Bernardo Alan de Freitas; Serfaty, Ricardo; Neto, Aristeu da Silveira

doi:10.1007/s10494-019-00025-z

Cited by 4 publications

(2 citation statements)

References 21 publications

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“…The transient equations were solved using the MFSim program, which has been developed over the last ten years in cooperation with a large research group and with the scientific support of Petrobras, a semipublic Brazilian multinational corporation in the petroleum industry, headquartered in Rio (6) de Janeiro, Brazil. For further details about the code and its previous works, the readers are invited to see [12,16,24]. All simulations were performed in a parallel environment in the fluid mechanics laboratory cluster at the Federal University of Uberlândia, Brazil.…”

Section: Mfsim Codementioning

confidence: 99%

Primary atomization of a turbulent liquid jet in crossflow: a comparison between VOF and FGVT methods

Duarte

Barbi

Villar

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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The primary atomization of a turbulent liquid jet in crossflow was investigated using a mathematical, numerical and computational model. A comparison between the standard volume of fluid (VOF) method and the fine grid volume tracking (FGVT) method was reported. The FGVT method advects the interface between two fluids using a finer grid than the employed by the standard VOF method, and according to the literature, it provides a better interface resolution. Simulations were performed using adaptive mesh refinement in a three-dimensional domain subjected to gravitational field using the in-house code MFSim. The flow was modeled using an Eulerian-Lagrangian approach to capture the interface. The interface was tracked initially with VOF or FGVT methods until the initial breakup. Broken off, small-scale nearly spherical drops were transferred into the Lagrangian point particle description. Column breakup and shear breakup modes were observed on the liquid jet. Drops were small as one-hundredth the size of the injector diameter. The model was validated against experimental correlations for the liquid jet column trajectory, and the droplet size distribution was compared to a previous numerical study from the literature. In addition, the breakup mechanisms predicted were qualitatively compared to those in previous reports. The results of the liquid column trajectory from the simulations performed presented low differences with the literature for both methods tested. According to the numerical results obtained from the computational simulations, the liquid column trajectory was well captured and the droplet size distribution was similar to the literature; however, the FGVT method provided higher accuracy compared to VOF method. The two main breakup modes were identified, namely the column breakup with Kelvin-Helmholtz instabilities and the surface breakup with the formation of multiple ligaments which later lead to droplet formation. The FGVT method provided a more detailed interface contour and improved the number of droplets converted from the Eulerian to the Lagrangian approach compared to the standard VOF method. On the other hand, the FGVT method presented relatively higher computational costs compared to VOF. Therefore, the FGVT method presented a higher interface quality and allowed a larger number of droplet conversion to the Lagrangian approach compared to the VOF method, even though the simulation run time using VOF was lower than with FGVT.

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Section: Mfsim Codementioning

confidence: 99%

Primary atomization of a turbulent liquid jet in crossflow: a comparison between VOF and FGVT methods

Duarte

Barbi

Villar

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

Self Cite

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“…When the Reynolds number of the liquid phase is low, the heat transfer is significantly enhanced. de Freitas Duarte et al 25 investigated the effect of bubble rising motion on the wall‐liquid heat transfer in a cubic cavity with a non‐isothermal field using the VOF method. Their results showed that the two‐phase average Prandtl number has a great influence on an increase or a decrease in the heat transfer rate.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigations on the effect of bubble injection on heat transfer of natural convection in laminar flows

Lei,

Pang

2023

Asia-Pacific J Chem Eng

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It was found that the injection of bubbles into liquid can effectively improve heat transfer efficiency, so it is important for industrial applications to investigate the effect of bubble injection on heat transfer. The effect of bubble injection on natural convective heat transfer in steady laminar flows in a vertical channel is investigated using the volume of fluid (VOF) method, and the effects of bubble diameter, Eötvös number (Eo), bubble arrangement, and bubble distance from a hot wall on the heat transfer between the hot wall and liquid are studied, respectively. The results show that bubble injection can effectively improve the heat transfer between the hot wall and liquid; an increase in bubble diameter and Eo can improve the enhancement effect of heat transfer and can expand the enhancement area of heat transfer; the closer to the hot wall a bubble is, the better the enhancement of heat transfer is; and the spacing and arrangement of bubbles also have important effects on the heat transfer between the hot wall and liquid. The comparison shows that the enhancement of heat transfer is the best for the vertical arrangement of double bubbles, which increases the local heat transfer coefficient by 3.2 times. The enhancement of heat transfer generated by bubble injection is related to the degree of disturbance of the local liquid phase caused by bubble injection. The more strongly the local liquid is disturbed, the thinner the local temperature boundary layer becomes, and the better the enhancement of heat transfer is.

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Implementation of a hybrid Lagrangian filtered density function–large eddy simulation methodology in a dynamic adaptive mesh refinement environment

et al. 2021

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Multispecies mixing processes play an important role in many engineering, biological, and environmental applications. Since simulating mixing flows can be useful to understand its physics and to study industrial issues, this work aims to develop the basis of a methodology able to simulate the physics of multiple-species mixing flows, using a hybrid large eddy simulation/Lagrangian filtered density function (FDF) method on an adaptive, block-structured mesh. A computational model of notional particles transport on a distributed processing environment is built using a parallel Lagrangian map. This map connects the Lagrangian information with the Eulerian framework of the in-house code MFSim, in which transport equations are solved. The Lagrangian composition FDF method, through the Monte Carlo technique, performs algebraic calculations over an ensemble of notional particles and provides composition fields statistically equivalent to those obtained by finite volume numerical solution of partial differential equations. Finally, to maintain high accuracy in the system of stochastic differential equations solver when an adaptive mesh refinement environment is used, a methodology for ensuring mass conservation is developed to preserve at least the statistical moments up to order two, even in the case of annihilation or cloning of a large number of notional particles in one time step, ensuring the applicability of Lagrangian FDF methods in dynamically adaptive grid refinement.

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Influence of the Prandtl Number on Wall-to-Fluid Thermal Transfer Rate in a Cubic Cavity

Cited by 4 publications

References 21 publications

Primary atomization of a turbulent liquid jet in crossflow: a comparison between VOF and FGVT methods

Primary atomization of a turbulent liquid jet in crossflow: a comparison between VOF and FGVT methods

Numerical investigations on the effect of bubble injection on heat transfer of natural convection in laminar flows

Implementation of a hybrid Lagrangian filtered density function–large eddy simulation methodology in a dynamic adaptive mesh refinement environment

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