Effect of double-diffusive convection with cross gradients on heat and mass transfer in a cubical enclosure with adiabatic cylindrical obstacles
| Autor: | Manu Chakkingal, Chris R. Kleijn, Roland Voigt, Sasa Kenjeres |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Convection
Double-diffusive convection Materials science Buoyancy Prandtl number 02 engineering and technology engineering.material 01 natural sciences Laminar flow 010305 fluids & plasmas Physics::Fluid Dynamics symbols.namesake Obstacles 0203 mechanical engineering 0103 physical sciences Double diffusive convection Fluid Flow and Transfer Processes Natural convection Mechanical Engineering Heat transfer enhancement Temperature gradient Mechanics Rayleigh number Condensed Matter Physics Lewis number 020303 mechanical engineering & transports symbols engineering Concentration gradient Quasi-steady flow |
| Zdroj: | International Journal of Heat and Fluid Flow, 83 |
| ISSN: | 0142-727X |
| Popis: | We investigate natural convection driven by a horizontal temperature gradient and a vertical concentration gradient in fluid-filled enclosures with obstructions inside it. Within the domain, nine adiabatic and impermeable cylinders are placed, occupying 30% of the domain volume. The Boussinesq approximation is used to account for density variations within the fluid and the flow is fully resolved. The solutal Rayleigh number has been fixed at R a C = 10 6 and the Prandtl number at P r = 5.4 . The Lewis number has been varied in the range of 1 ≤ Le ≤ 100 and the buoyancy ratio in the range of 0.1 ≤ |N| ≤ 10. The rate of heat and mass transfer are compared to those found in single-scalar natural convection, i.e solely thermal or concentration driven convection. Besides, the obtained heat and mass transfer rate in the cylinder-packed enclosure have been compared to those found in a fluid-only domain. We observe that the addition of a destabilizing concentration gradient to a side-heated enclosure results in heat transfer enhancement, which decreases with Lewis number and thermal Rayleigh number. Similarly, the temperature gradient increases the mass transfer, especially at high Lewis numbers and lower concentration buoyancy force over its thermal counterpart. Although the presence of the cylindrical obstacles reduced the flow velocity, the mass transfer was enhanced at lower buoyancy ratio. |
| Databáze: | OpenAIRE |
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