the effect of wind on combined convective loss from a bicylindrical cavity receiver: an experimental study

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%#