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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 3 - WATER ENGINEERING AND CIVILIZATION : The Brief Introduction for Theory of Cavitation Cavity Endangering Stability of Hydraulic Machinery
The Brief Introduction for Theory of Cavitation Cavity Endangering Stability of Hydraulic Machinery
Author : Hongquan Xu, Li Lu, Wanpeng Wang and Tieyou Li
With the increase in the size and capacity of hydropower unit, operation stability of hydropower station becomes more and more important. The brief introduction is made for ?theory of cavitation cavity endangering stability of hydraulic machinery? which is advanced firstly by the author in 2012. Firstly, the definition are presented for the cavitation cavity, which is defined as ?cavitation bubbles conglomeration? or ?cavity? with some cubage coming from cavitation, and the differences between cavitation cavity and cavitation bubbles on the existence form and endangering to hydraulic machinery are presented separately. The cavitation cavity is divided into vortex flow type and non-vortex flow type according to basic forming reason. Secondly, based on the theoretical analyses of hydraulic machinery unstable phenomenon, the main connotation of this theory is proposed. The endangering scope of cavitation cavity, the multiplication effect of endangering and the basic reason of endangering are analyzed, and then two main enlarged styles to pressure fluctuation due to cavitation cavity are interpreted, one is cyclical variation of ?expanse- compression?, the other is sudden change of ompression?, the o? to flow passage. The principal way that unstable energy is accumulated by cavitation cavity is also discussed. Thirdly, peripheral force driving vortex flow is analyzed according to the classification of vortex flow. The relationship between the maximum flow velocity and space size for space limited vortex flow is demonstrated, estimation formula for the dimension of vortex vacuole accumulation is presented, similarity relation of the hydraulic stability affected by the vacuole accumulation between model and prototype turbine are analyzed thoroughly. Fourthly, the effect principle for air admission is interpreted through this theory, the endangering and enlarging effect of cavitation cavity are analyzed in the hydraulic machinery unstable phenomenons thereby the main framework and connotation are established for ?theory of cavitation cavity endangering stability of hydraulic machinery?.
File Size : 170,449 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Date Published : 18/07/2016
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