Wind pressure and wind-induced vibration of heliostat

Heliostat is the key part of Solar Tower power station, which requires extremely high accuracy in use. But it's sensitive to gust because of its light structure, so effect of wind load should be taken into account in design. Since structure of heliostat is unusual and different from common ones, experimental investigation on rigid heliostat model using technology of surface pressure mensuration to test 3-dimensional wind loads in wind tunnel was conducted. The paper illustrates distribution and characteristics of reflector's mean and fluctuating wind pressure while wind direction angle varied from 0 to 180 and vertical angle varied from 0 to 90. Moreover, a finite element model was constructed to perform calculation on wind-induced dynamic response. The results show that the wind load power spectral change rulers are influenced by longitudinal wind turbulence and vortex and are related with Strouhal number; the fluctuating wind pressures between face and back mainly appear positive correlation, and the correlation coefficients at longitudinal wind direction are smaller than those at lateral direction; the fluctuating wind pressures preferably agree with Gaussian distribution at smaller vertical angle and wind direction angle. The wind-induced response and its spectrums reveal that: when vertical angle is small, the background responsive values of reflector's different parts are approximately similar; in addition, multi-phased resonant response occurring at the bottom. With the increase of θ, airflow separates at the near side and reunites at the other, as produces vortex which enhances dynamic response at the upper part.