Development and calibration of an experimental test bench simulating solar reflectors erosion

The main objective of this paper is to design, calibrate and make functional a horizontal test bench used to carry out the experimental simulation of solar reflectors erosion induced by sand particles. The developed equipment provides the possibility to control the air speed, the impact angle between the fluid flow and the target surface as well as the mass rate of the ejected particles. The originality of this work lies on the introduction of a new parameter, identified as, the unified sand mass received by the samples in each test, without considering the experiments conditions (air speed, impact angle, etc.) by acting on the ejected sand mass poured in the sand container. To make the setup operational, a set of calibration tests was conducted under multiple scenarios. The collected data from the calibration tests were analyzed to choose the appropriate configuration. A multiple linear regression function was applied to analyze the influence of the inputs parameters on the tests repeatability. A descriptive equation calculating the amount of sand needed to ensure the unified sand mass, homogeneity and repeatability of the experiments is introduced. The results of erosion simulation carried on solar glass reflectors are also presented; for an air speed of 25 m/s, the reflectance loss is two times greater in 90° (11.03%) than the registered in 45° (5.31%). The developed bench should help researchers to set up their devices for the conduction of advanced experiments ensuring that the obtained results are as repeatable as efficient.