In this work, we employed experimental technique to study the issue of particle erosion and deposition in multiphase flows involving both particles of micro/meso- and nanoscale (sand particles and iron oxide particles). Especially, liquids with immersed nanoparticles gained a lot of interest in the recent years due to their enhanced thermal properties. At the same time, this type of fluids is still not widely used in practical and engineering applications, and one of the reasons is a risk of leading to erosion and deposition on, for instance, pipe walls. In our experiments, an aluminum plate was subjected to a flow with particles by immersing it in a beaker with a rotating fluid for 530 h. After this, the plate was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM), followed by energy dispersive X-ray (EDX) analysis. According to our observations, the erosion was mainly caused by the largest particles (sand particles), while the nanoparticles did not lead to clear erosion but resulted in significant deposition due to strong adhesion, as well as corrosion, resulting in aluminum oxide formation. This issue was also confirmed through theoretical analysis by comparing the momentum response time and the characteristic time of the flow, as well as computational fluid dynamics (CFD) simulations.

中文翻译：

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研究颗粒流动引起的侵蚀和沉积


在这项工作中，我们采用实验技术研究了涉及微/中尺度和纳米级颗粒（沙粒和氧化铁颗粒）的多相流中的颗粒侵蚀和沉积问题。特别是，由于具有增强的热性能，浸没纳米颗粒的液体近年来引起了人们的广泛兴趣。同时，这种类型的流体仍未在实际和工程应用中得到广泛应用，原因之一是存在导致腐蚀和沉积的风险，例如管道壁。在我们的实验中，通过将铝板浸入装有旋转流体的烧杯中 530 小时，使其与颗粒一起流动。在此之后，使用扫描电子显微镜 （SEM） 和原子力显微镜 （AFM） 研究板，然后进行能量色散 X 射线 （EDX） 分析。根据我们的观察，侵蚀主要是由最大的颗粒（沙粒）引起的，而纳米颗粒没有导致明显的侵蚀，但由于强粘附性导致显着沉积，以及腐蚀，导致氧化铝的形成。通过比较动量响应时间和流动的特征时间，以及计算流体动力学 （CFD） 模拟的理论分析，也证实了这个问题。