空化水流与水流空化数的压强差当量表述

Cavitation flow and the description to pressure equivalent of cavitation numbers

引用"物态"与"物像",以及"像"为"态"的"当量"表述等概念,以四个数轴的图形解析方式,比较了三种空化数的压强(差)当量与压应力状态的相对关系。从水流空化状态的客观发展过程和描述各个空化状态的空化数的物理意义出发,分析了各种空化数的数值描述与空化水流状态的不对应性。指出了托马斯空化数等不宜作为水流空化的状态描述及相似性代表的本质。并间接提醒人们,以数学方程式描述客观的自然现象,首先不能超越物理学的基础边界。否则,其推导结论很难与客观的工程实际问题相互对接。

Relative relationships between pressure equivalent and pressure stress state are compared for three different cavitation numbers by using the concepts of matter state and matter image and taking image as state equivalent in graphical expressions in a 4-axises system.Based on the physical process of water cavitation phenomenon and the physical meaning of cavitation numbers,non-corresponding situations of the quantitative expression of cavitation numbers to the cavitation flow state are analyzed.The analysis results show that the cavitation numbers have some defects in representing cavitation condition or being used as a similitude criterion.This suggests that any mathematical formula description of physical phenomenon should not be beyond its physical boundary,and otherwise its correspondence to the practical engineering problems would become difficult.