The Effect of Wind on Combined Convective Loss from a Bicylindrical Cavity Receiver: An Experimental Study
Volume Title: 1
Department of Chemical Engineering, University of Sistan and Baluchestan, Zahedan, Iran
The performance of the solar cavity receiver is considerably affected by wind specifications in the parabolic dish system. In this paper, an experimental study is performed to investigate the effect of wind speed, wind direction, and cavity inclination on the combined convective loss from a bicylindrical cavity receiver. The steady-state experiments are carried out in the range of 0.3 to 5.7 m/s wind speeds and three wind directions, including side-on, head-on, and back-on wind for downward-facing and horizontal cavity situations. The results show that the head-on wind causes higher combined convective loss comparing the other two wind directions for all wind speeds and cavity inclinations except 90° (vertically downward-facing) where all three wind directions essentially act the same. For the horizontal cavity receiver, the forced convective loss is less than the natural convective loss for all wind directions and speeds. Empirical correlation is also developed for combined Nusselt number as a function of Reynolds number, Grashof number, cavity inclination, wind direction, and the absolute temperature ratio for the downward-facing cavity. Comparing the proposed correlation combined Nusselt number with experimental results shows a maximum deviation of 20%.