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

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,...

Rayleigh-Bénard convection of a supercritical fluid: PIV and heat transfer study

Fluids above the critical point are widely used in industry. Chemical, pharmaceutical, food industry and energy production are some examples. In the energy production sector they are mainly used as cooling fluids, because they allow to increase the thermal efficiency of the power plants. However, the fundamentals of their heat transfer behavior...

Natural convection driven heat transfer in fluids with strongly variable properties: A particle image velocimetry study

The High Performance Light Water Reactor (HPLWR) is one of the six innovative nuclear energy systems proposed by the Generation IV International Forum. The use of water at supercritical pressure as the coolant in the HPLWR allows a significative increase of the thermal efficiency of the power plant, a reduction in size and complexity of the...

Long-term unsteadiness and large-scale structures in Rayleigh-Bénard convection with and without electromagnetic forcing

This dissertation focuses on turbulent thermal convection, which occurs in a wide range of (geo)physical situations, like in the atmosphere, the oceans, the interior of stars or planets, and engineering applications, like metal casting or crystal growth processes. In this work, a special type of thermal convection, Rayleigh-Bénard convection, is...