Heat-source driven convection in tall cavities

T. H. Reif, A. A. Shabayek, F. A. Kulacki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This investigation considers a tall, two-dimensional cavity with adiabatic side and bottom walls and a fixed temperature at the upper boundary. All boundaries are rigid, no-slip surfaces. The energy generation within the fluid is treated as a constant. Six aspect ratios are investigated. A commercially available CFD code is used to solve the turbulent equations of conservation of mass, momentum, and energy. These equations are normalized, and the effects of reference velocity on convergence are investigated. The choice of reference velocity affects numerical stability, and the most favorable scaling is when the Reynolds number is the square root of the Grashof number, as opposed to the conventional inverse of the Prandtl number. Mesh convergence is confirmed. Under-relaxation, steady-state modeling is used. Typical convergence criteria are not feasible at higher Rayleigh numbers. Rather, the maximum difference convergence criteria is set at unobtainable values, and steady-state convergence is based on an acceptable energy balance between the internal heat generation and heat transfer at the free surface. The model is validated using published experimental data and numerically verified using available finite difference and finite element solutions. Rayleigh numbers range from 104 to 108 for the six aspect ratios and the fixed Prandtl number of 6.5. Temperature, stream function, turbulent kinetic energy, and velocity vectors are calculated for each of these cases and selected results are presented. Heat transfer results indicate the absence of a universal correlation of the Nusselt number with Rayleigh number and aspect ratio.

Original languageEnglish (US)
Title of host publicationProceedings of the 3rd Thermal and Fluid Engineering Summer Conference, TFESC 2018
PublisherBegell House Inc.
Pages443-454
Number of pages12
ISBN (Electronic)9781567004724
DOIs
StatePublished - 2018
Event3rd Thermal and Fluid Engineering Summer Conference, TFESC 2018 - Fort Lauderdale, United States
Duration: Mar 4 2018Mar 7 2018

Publication series

NameProceedings of the Thermal and Fluids Engineering Summer Conference
Volume2018-March
ISSN (Electronic)2379-1748

Conference

Conference3rd Thermal and Fluid Engineering Summer Conference, TFESC 2018
Country/TerritoryUnited States
CityFort Lauderdale
Period3/4/183/7/18

Bibliographical note

Publisher Copyright:
© 2018 Begell House Inc.. All rights reserved.

Keywords

  • Finite element method
  • Internal energy generation
  • Natural convection
  • Nusselt number
  • Rayleigh number
  • Tall cavities

Fingerprint

Dive into the research topics of 'Heat-source driven convection in tall cavities'. Together they form a unique fingerprint.

Cite this