Influence Factors And Appraise Of Hydraulic Cavitation Occurring

Cavitation is a kind of very complicated fluid phenomenon,cavitation bubbles while exercising and collapsing in the liquid can give out partial heat high pressure, light,turn on electricity, pound at wave,high speed to shoot and glow an extreme physical condition etc. In the water power machine,the cavitation should be avoided as far as possible, in order to prevent from damages the machine, but this kind of characteristics also can be used by us.This dissertation is aimed at finding out the mechanism of hydraulic cavitation and the evolution of bubble dynamics,knows that the cavitation evolution rule,establishes the relation between the hydraulic cavitation effect and the throttling device design parameter,then optimizes the throttling device design,seeks the best cavitation condition, provides the theory basis and the instruction for the hydraulic cavitation project practical application.This thesis design a set of practical effective hydraulic cavitation test installation,this equipment takes the hydraulic cavitation generator by the multi-hole orifice,Uses the high-speed photography study the multi-hole orifice design parameter to the hydraulic cavitation effect influence,summarizes the efficacious device of obtaining the appraisal hydraulic cavitation effect.The earlier period has studied the same opening ratio of34multi-hole orifice to the pipeline throttle characteristic influence,analyze the experiment to know,the multi-hole orifice has the center opening,increases the multi-hole holes,avoids the peculiar circumstance being possible as far as possible to cause the pipeline resistance loss to reduce obviously.This experimental design two sets of multi-holes:The7different opening ratio and the same6opening ratio multi-holes,have the explicit stipulation in the hole distribution.Through imagery processing and pipeline characteristic research,exploration the multi-hole orifice design parameter to the hydraulic cavitation effect influence.The result show that,using the average grey level of the orifice may reflect the cavitation effect well;Through a single orifice for image processing,with the flow increasing,the pipeline’s average grey level has3inflection points,analysis shows that the two average gray difference could be able to appraise the cavitation effect well; Through analysis and comparison of two groups of orifice,the opening ratio is the predominant factor to affect the hydraulic cavitation effect,each pipeline has a best opening ratio (this test equipment is0.0478),causes the pipeline hydraulic cavitation effect to be most superior;In the same opening ratio situation, in a few holes when there are fewer, along with the holes increasing,the pipeline’s maximum flow increases,resistance coefficient obvious reduction; When the hole a few more (this experiment orifice is13), the pipeline’s maximum flow and the resistance coefficient have the big fluctuation,pipeline’s average grey level also have the very big fluctuation;comparison of the experimental analysis are all derived:the opening ratio is0.0478and the holes is25(5orifices) are the most superior orifice of the experimental device cavitation effect.