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A numerical and experimental study on turbulent natural convection in a differentially heated cavity

Rouwenhorst, Driek (2011) A numerical and experimental study on turbulent natural convection in a differentially heated cavity.

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Abstract:The three-dimensional flow field and temperature distribution in a differentially heated vertical cavity is identified by means of different numerical models and experimental measurement techniques. Numerically, the performance of different turbulence models are validated with DNS data available in literature. The main results will be published in the XXXII Iberian Latin-American Congress on Computational Methods in Engineering (CILAMCE). A model with sufficient performance will be used to simulate the ow in the experimental setup to give an accurate description of the phenomenon. Along specific contours the velocity field is measured experimentally in two dimensions applying Laser Doppler Velocimetry (LDP). For a more global overview of the fow behavior Particle Image Velocimetry (PIV) is used in some cross-sectional planes. In addition, the temperature distribution in the ow is visualized exploiting the Liquid Crystal Thermography (LCT) measurement technique. Finally, the heat flux distribution from the heated walls to the fluid is obtained by the positioning of an array of flux sensors. The classifying Rayleigh number is defined by the height of the cavity, which is related to its square base by an aspect ratio of four. Numerically RaH = 6; 4 x 108 and 1010 are considered with air as working uid (Pr = 0:71), making it possible to compare the results with available DNS data. In the experiments wa- ter is used (Pr = 7:0) and is exposed to a temperature difference such that RaH = 1 x 1010 is achieved, where the ow is measured with the non-intrusive techniques. The experimental results will complement existing data at lower Rayleigh numbers available in literature. The main object is to extend the availability of accurate experimental data on natu- ral convection in differentialy heated cavities. This data can be exploited to validate different numerical methods, trying to capture the behavior of turbulent natural convection in the most efficient way. The work under- lined above is the graduation project of André Popinhak, in which I was assigned to assist. The activities had already begun before the internship started and was not finished before the end of this period, therefore the subjects descibed are representative for the learned theory and performed tasks of the internee rather then a complete description of the research carried out.
Item Type:Essay (Master)
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
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