TY - JOUR
T1 - Effect of surface roughness on heat transfer in Rayleigh-Bénard convection
AU - Tummers, Mark J.
AU - Steunebrink, Martin
PY - 2019
Y1 - 2019
N2 - 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.
AB - 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.
KW - Heat transfer enhancement
KW - Natural convection
KW - Particle image velocimetry
KW - Rayleigh-Bénard convection
KW - Surface roughness
KW - Thermochromic liquid crystals
UR - http://www.scopus.com/inward/record.url?scp=85066330795&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatmasstransfer.2019.05.066
DO - 10.1016/j.ijheatmasstransfer.2019.05.066
M3 - Article
AN - SCOPUS:85066330795
SN - 0017-9310
VL - 139
SP - 1056
EP - 1064
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
ER -