In the present paper, experiment on liquid droplet impinging erosion is described using high-speed spray. The droplet parameters of this phenomenon, such as droplet velocity, diameter and number of impinging droplets, are measured by using optical techniques, such as particle image velocimetry, shadowgraph and laser-light extinction method, respectively. The present measurement of droplet parameters indicates that the droplet velocity is up to 230m/s and the droplet diameter is tens of micrometers, which are expected to be those of prototype pipeline condition in nuclear power plant. The number density of impinging droplets is an order of 106-108 (mm-2s-1). The observation of erosion on a stainless steel in the laboratory test shows a pear-like surface roughness pattern having a few hundred um, which is found to be much larger than the impinging droplet diameter of a tens of um.

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