Boiling flow simulations on adaptive octree grids

Akhtar, M. Wasy; Kleis, Stanley J.

doi:10.1016/j.ijmultiphaseflow.2013.01.008

Cited by 34 publications

(27 citation statements)

References 32 publications

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“…g. Film boiling: the phase change model developed was used to study film boiling in both two and three dimensions. The average wall Nusselt number of the film boiling simulations presented by Akhtar and Kleis [1] agreed well with the widely accepted correlations of Berenson [8], Klimenko [18] and Klimenko and Shelepen [19] with AMR efficiency, in the range of 50-80%. A detailed grid convergence study was carried out to show the consistency and thus, convergence of the numerical scheme in both space and time.…”

Section: A Fluent™ Verification (Other Investigations): Studies Done Bysupporting

confidence: 83%

“…Following are some of the validation test case descriptions, presented in Akhtar and Kleis [1], used to verify the accuracy and consistency of the model:…”

Section: Verification Test Results For Adaptive Gridsmentioning

confidence: 99%

“…(5) and (6)) and stored in a memory location for each cell. This approach of calculating mass source has been validated in the test cases studied by Akhtar and Kleis [1] and other works including that of Welch and Wilson [37]. Finally, the source functions for liquid mass, vapor mass, mixture momentum and energy are called, which calculate and return the values for each computational cell to Fluent™.…”

Section: Solution Proceduresmentioning

confidence: 99%

“…The phase change model on adaptive octree grids has also been described in detail and validated in Akhtar [2] and Akhtar and Kleis [3]. This model has been used and further validated in the subsequent work on computations of boiling flows on adaptive grids [1] as described in the next section on Verification Test Results for Adaptive Grids.…”

Section: Solution Proceduresmentioning

confidence: 99%

“…The interface capturing scheme, having been verified by a suite of test cases for various aspects of the model [1], is used next to simulate the approach problem, i.e., a vapor bubble approaching and interacting with an inclined superheated wall.…”

Section: Vapor Bubble Approaching An Inclined Superheated Wallmentioning

confidence: 99%

See 4 more Smart Citations

Vapor bubble approaching a superheated wall

Akhtar

Kleis

Hollingsworth

2015

International Journal of Heat and Mass Transfer

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Section: A Fluent™ Verification (Other Investigations): Studies Done Bysupporting

confidence: 83%

“…Following are some of the validation test case descriptions, presented in Akhtar and Kleis [1], used to verify the accuracy and consistency of the model:…”

Section: Verification Test Results For Adaptive Gridsmentioning

confidence: 99%

Section: Solution Proceduresmentioning

confidence: 99%

Section: Solution Proceduresmentioning

confidence: 99%

Section: Vapor Bubble Approaching An Inclined Superheated Wallmentioning

confidence: 99%

See 3 more Smart Citations

Vapor bubble approaching a superheated wall

Akhtar

Kleis

Hollingsworth

2015

International Journal of Heat and Mass Transfer

Self Cite

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

Duarte

Serfaty

Neto

2019

Flow Turbulence Combust

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An extension of Oberbeck–Boussinesq approximation for thermal convection problems

Duarte

Melo

Villar

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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An extension of the Oberbeck-Boussinesq approximation (OB) with expressive thermal effects is investigated to model specific mass with a temperature-dependent approach. An expansion of OB is proposed using a mathematical formulation with null velocity divergence in the continuity equation and variable specific mass in the momentum and energy equations (NOB). The NOB method has been previously tested in the literature, and the present paper aims to carry out a quantitative analysis between NOB and OB. The specific mass is calculated based on the temperature field and a divergence-free velocity is imposed on the NOB due to the small effects of variations of the specific mass in the continuity equation, as previously demonstrated by the OB. The purpose of the NOB is to overcome the OB's restriction to single-phase flows, as well as to model the effects of specific mass variations more accurately, especially in problems with prominent thermal transfer effects, as that occur in the turbulent regime. Since the effects of a variable specific mass in the momentum and energy equations were taken into account by the NOB, it was expected that the thermal transfer results of the NOB would be improved compared with those of the OB. Then, three-dimensional natural convection simulations for a large range of Rayleigh numbers were performed using OB and NOB in a cubic cavity. Turbulence modeling was performed using Large Eddy Simulation (LES). Numerical results from both approaches were validated and all the results presented good quality. Thermal transfer was evaluated by the calculation of the Nusselt number at the heated wall and compared to experimental data from the literature. The OB and NOB provided adequate thermal transfer rate results; however, the differences between the literature and OB were higher than for NOB. Therefore, NOB is presented as a useful mathematical formulation for modeling incompressible flows with a temperature-dependent specific mass approach in single-phase or multiphase problems instead of solving the full compressible mathematical formulation. In addition, the differences between the literature and OB results increased as the Rayleigh number was raised, especially in the turbulent regime. The results of the NOB were closer to the literature than were those of the OB for the entire range of Rayleigh numbers tested. Therefore, the numerical results confirmed the higher accuracy of NOB compared to OB despite the NOB's still being an approximate model. Lastly, flow visualization allowed the identification of coherent turbulent structures near the cavity walls in the simulation with Rayleigh number 10 10. The presence of hairpin and Tollmien-Schlichting instabilities revealed the importance of modeling the three-dimensional effects of natural convection in the turbulent regime.

show abstract

Boiling flow simulations on adaptive octree grids

Cited by 34 publications

References 32 publications

Vapor bubble approaching a superheated wall

Vapor bubble approaching a superheated wall

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

An extension of Oberbeck–Boussinesq approximation for thermal convection problems

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