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a b s t r a c tA three-dimensional numerical approach incorporating the radiation, solar load, and turbine models proposed in this paper was first verified by the experimental data of the Spanish prototype. It then was used to investigate the effects of solar radiation, turbine pressure drop, and ambient temperature on system performance in detail. Simulation results reveal that the radiation model is essential in preventing the overestimation of energy absorbed by the solar chimney power plant (SCPP). The predictions of the maximum turbine pressure drop with the radiation model are more consistent with the experimental data than those neglecting the radiation heat transfer inside the collector. In addition, the variation of ambient temperature has little impact on air temperature rise despite its evident effect on air velocity. The power output of the SCPP within the common diurnal temperature range was also found to be insensitive to ambient temperature.

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The impact forces of the low-speed water droplet colliding on a light and tiny aluminum plate were measured by using a highly sensitive piezoelectric force transducer. The one-degree freedom vibration model was employed to analyze the oscillation of the measured force signals, and the plate vibration was confirmed as the cause through elaborately designed experiments. The force data were obtained by using the low-pass Finite Impulse Response filter and was verified to be reliable. The effects of impact velocity and diameter of droplets on the impact force evolutions and peak forces were investigated. The results revealed that the impact process of a liquid droplet is quite different from that of a solid ball in the frequency spectrum and in the power function of the peak force. The droplet impact is closer to a plastic impact, while the other behaves more nearly an elastic impact. The influence of droplet size on erosion is dependent on the impact time duration, which increases with droplet diameter. On the other hand, the impact pressure is the main cause of the material erosion when impact velocity is taken as the influence factor.

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