不同弹性材料空蚀特性试验

在水利工程的泄水建筑物中，弹性材料作为抗空蚀材料具有极为广阔的应用前景，研究空化泡与不同边界材料的相互作用，探索弹性材料抗空蚀的机理，具有明确的现实意义和理论价值。本文通过开展不同弹性材料超声空蚀实验，以宏观和微观角度观察分析不同弹性材料的空蚀特征，研究材料抗空蚀性能的影响因素。其中，弹性材料主要包括216-1硅胶、216-2硅胶、218-1硅胶、218-2硅胶、聚氨酯、软质聚氯乙烯、硬质聚氯乙烯、酚醛层压板、低密聚乙烯、高密聚乙烯、聚酰胺等材料，对应的拉伸弹性模量范围为1-4660MPa。主要得到以下结论：(1)弹性模量1-11MPa的弹性材料在超声空化作用下没有出现空蚀质量损失，另外弹性材料的表面仅有些细小的纹理变化，没有出现破裂或孔洞，表明在这一弹性模量范围的弹性材料具有较好的抗空蚀特性。(2)随着弹性模量增加，不同弹性材料的空蚀破坏特征有较明显的差别，说明此时材料抗空蚀特性与弹性模量的关联性下降，与材料密度、结构等特征有关：高密度、结构致密的材料空蚀质量损失和表面粗糙度变化很少；密度较低、结构稀疏的材料有明显空蚀质量损失和表面粗糙度增加。另外，材料表面缺陷处更容易发生空蚀破坏。研究结论可为弹性抗空蚀材料的研发和应用提供理论支撑。

Cavitation Erosion Characteristics Experiment of Materials with Different Elasticitys

The outlet structures of in hydraulic engineering, elastic materials have a very broad application prospect as anti-cavitation materials. It has clear practical significance and theoretical value to study the interaction between cavitation bubbles and different material boundaries and explore the anti-cavitation mechanism of elastic materials. By carrying out ultrasonic cavitation erosion experiments of materials with different elasticities, the paper analyzes the cavitation erosion characteristics of different elastic materials from the macro and micro perspectives, and studies the factors affecting the anti-cavitation properties of materials. Among them, elastic materials mainly include 216-1 silica gel, 216-2 silica gel, 218-1 silica gel, 218-2 silica gel, polyurethane, soft polyvinyl chloride, rigid polyvinyl chloride, phenolic laminate, low-density polyethylene, high-density polyethylene, polyamide and other materials, and the corresponding tensile elastic modulus ranges from 1 to 4660mpa. The main conclusions are as follows: (1) The materials with an elastic modulus of 1-11MPa have no erosion mass loss under ultrasonic cavitation. In addition, the surface of the elastic material has only small texture changes and no crack or hole on the morphologies, which shows their well anti-cavitation characteristics. (2) With the elastic modulus increasing, the cavitation erosion characteristics of different elastic materials have obvious differences, indicating that the correlation between the anti-cavitation properties of materials and their elastic modulus decreases, but it is related to the material density, structure, etc. Higher density and densely structured materials have less erosion mass loss and surface roughness, while lower densely structured materials have more erosion mass loss and increased surface roughness, and cavitation erosion is more likely to occur at the defects on the surface of the materials.