Effect of surface roughness on heat transfer in Rayleigh-Bénard convection

Tummers, M.J.; Steunebrink, M.

doi:10.1016/j.ijheatmasstransfer.2019.05.066

Effect of surface roughness on heat transfer in Rayleigh-Bénard convection

Title

Effect of surface roughness on heat transfer in Rayleigh-Bénard convection

Author

Tummers, M.J. (TU Delft Fluid Mechanics)
Steunebrink, M. (TU Delft EKL-Users)

Date

2019

Abstract

This paper reports on an experimental study of the effects of surface roughness on the flow and heat transfer in cubical Rayleigh-Bénard convection cells for Rayleigh numbers between 10⁷ and 10¹⁰. In the rough cells the top and bottom surfaces are equipped with square arrays of copper cubes. In line with other studies, three different regimes occur in the rough cells, with each regime having a different relation between the Nusselt number, Nu, and the Rayleigh number, Ra. In the first regime the Nu-Ra relation equals that of the smooth cell, but in the second and third regimes the Nu-Ra relation deviates from that of the smooth cell with significantly higher Nusselt numbers. To better understand these observations, the flow and temperature fields in both the smooth and rough cells were visualised by using particle image velocimetry with suspended thermochromic liquid crystals as flow tracer particles.

Subject

Heat transfer enhancement
Natural convection
Particle image velocimetry
Rayleigh-Bénard convection
Surface roughness
Thermochromic liquid crystals

To reference this document use:

http://resolver.tudelft.nl/uuid:67d7b457-a925-4f8b-abf1-6517a35b2cdc

DOI

https://doi.org/10.1016/j.ijheatmasstransfer.2019.05.066

ISSN

0017-9310

Source

International Journal of Heat and Mass Transfer, 139, 1056-1064

Part of collection

Institutional Repository