本文从流体运动学、流体动力学的基本理论出发,揭示出流体机械产生空蚀的真正原理;论证了发生空蚀时,空穴泡消失产生的高压、高温和高浓度的化学活性物质(O2、CO2)与自然界的温度、气压及流体机械结构的关系。依据这一原理指出预防空蚀的方法—采用或喷涂耐高压、高温、高浓度活性物质腐蚀的材料—有一定弹性的微晶玻璃或非金属硬质材料。同时,本文介绍了根据得出的空蚀机理和预防方法,采用非金属硬质材料、运用等离子喷涂方法制作水泵叶轮抗空蚀涂层的工艺方法。经水泵空蚀试验,一方面验证了空蚀机理的正确性;另一方面证明采用非金属硬质材料、运用等离子喷涂方法制作的抗空蚀涂层的使用寿命要比现在正在使用中的高分子材料涂层的使用寿命大许多倍。为对流体机械空蚀原因的了解、流体机械空蚀的解决提供了一种新思路。 Based on the basic theory of fluid kinematics and fluid dynamics, this paper reveals the real principle of cavitation in fluid machinery. It is demonstrated that the formation of high pressure, high temperature and high concentration of chemical active substances (O2 , CO2) and the nature of the temperature, pressure and fluid mechanical structure. According to this principle pointed out that the method of preventing cavitation - using or spraying high pressure, high temperature, high concentration of active material corrosion of the material - a certain flexibility of glass-ceramics or non-metallic hard materials. At the same time, this paper introduces the method of making anti-cavitation coating of pump impeller by using non-metallic hard material and plasma spray method according to the cavitation erosion mechanism and prevention method. The pump cavitation test, on the one hand, verifies the correctness of the cavitation mechanism. On the other hand, it proves that the service life of the anti-cavitation coating made by the plasma spraying method is higher than that of the non-metallic hard material currently being used Molecular material coating life many times. In order to understand the cause of fluid mechanical cavitation, fluid mechanical cavitation provides a new idea.