Wind tunnel measurements of forced convective heat loss from multi-megawatt cavities of solar central receiver systems

We investigated the forced convective heat loss from a model of a multi-megawatt cavity receiver of a concentrated solar power (CSP) tower system in a high-pressure wind tunnel. Measurements of 5 geometrical configurations of this model as well as measurement uncertainties are reported in this contribution. The experiment covered a Reynolds number range of between 2·106 and 8·106, based on the external dimensions and flow field. In general, the measured values are highly sensitive to the geometrical configuration, the wind velocity, and the wind direction. The results show that the maximum forced convective heat loss for all configurations occurs when the wind blows from frontal directions of between 60° and 80° relative to the tower symmetry plane. We found that the peak location does not vary for different inclinations, but does vary for different aperture openings. Also, the results show that the direction of the wind causes the forced convective heat loss to vary with a factor of up to 6.1, but at least with a factor of 2.6. Last but not least, our power-law correlation of the dependency of the forced convective heat loss on the Reynolds number matches literature values.