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一、前言在离心泵的过流部位内,当局部地区的静压下降到当时水温相应的饱和蒸汽压力之后,水就发生汽化,这种现象叫气穴。可见气穴现象是水的沸腾现象,也就是热力学的现象。因此,水在热状态下的性质,象压力、温度、气化潜热以及比热等必然会对气穴现象产生影响。为说明热力学对气穴性能的影响(在NPSH一定时,高温有利于气穴的减轻),斯达尔(Sthl)等人首先提出了系数B。从那以后,发表了很多研究成果。其研究内容大多是水以外的液体,发展了象丁烷、苯、甲醇、氰11、液态氢、汽油等多种液体的气穴予测方法,並且推导出了许多不含有系数B的气穴判别式。然而,本文只介绍在以水为研究对象时,温度对气穴性能的影响。首先说明一下最先使用的系数B。
I. Introduction In the overcurrent portion of the centrifugal pump, when the static pressure in some areas drops to the corresponding saturated vapor pressure at that time, the water evaporates. This phenomenon is called cavitation. Cavitation can be seen that the phenomenon of boiling water, that is, the phenomenon of thermodynamics. Therefore, the nature of water in a hot state, such as pressure, temperature, latent heat of vaporization and specific heat, inevitably affects cavitation. To illustrate the effect of thermodynamics on cavitation performance (high temperatures favored cavitation mitigation at a given NPSH), Sthl et al first proposed the coefficient B. Since then, many research results have been published. Most of its contents are liquids other than water, and development of gas cavitation methods such as butane, benzene, methanol, cyanogen 11, liquid hydrogen, gasoline and many other liquids have been developed, and many cavities without coefficients B have been deduced Discriminant. However, this article only describes the effect of temperature on cavitation performance when using water as the research object. First explain the first use of the coefficient B.