Visual Study On Steady Flow Cavitation Number In The Pipeline

Cavitation is a common physical phenomenon, cavitation occurred in liquidmedium is a unique phenomenon in the hydraulic machinery, and generally does notoccur in solids and air space. Cavitation is widespread in turbines, pumps, valves andgates, ship propellers, water conservancy, sonar, water jet machining and cleaningequipment, as well as the engine’s nozzle. Collapsing cavitation bubbles near solidwall not only will cause damage to ships, submarine propeller and other hydraulicmechanical surface, affect its service life, but also to change their dynamic properties.Cavitation is an important indicator to reflect the turbine, water pumps, is issues mustbe taken into account in the design, testing, operation, and is an important researchtopic in the field of hydraulic machinery both here and abroad. Especially in recentyears, many research institutions and schools in the research of nozzle hole, because ofits important functions on the atomization.According to the theory of fluid mechanics, the flow field with fixed boundary,along streamlines speed more high, and pressure more low, When the pressure dropsbelow the saturated vapor pressure of liquid, in stream field of critical low pressuredistrict within, will produces cavitation, contains small bubbles in the cavitation area,it exists makes liquid phase fluid of continuity was damage, cavitation replacementfluid, stream state occurred changes, in stream road within formed steam bubble, andliquid in the is not dissolved gas and liquid of two-phase mobile, this is the so-calledcavitation phenomenon.Based on the visualization pipeline to study the cavitation phenomenon, throughthe study of different outlet pipe diameter, different outlet pipe inclination angle,different outlet pipe at the entrance of the chamfer and different the bell of differentstructure parameters and different entrance pressure, pressure other and parameters ofthe cavitation phenomenon, through the study of location of different structure ofcavitation phenomenon reasonably explanation,and summarize the universal cavitation number formula of conclusion and new structural conditions, especially the formulastructure cavitation new can make a reasonable explanation for the different structuralconditions of cavitation. A formula of the number of structure cavitation and on theother hand, also can make additions and improvements to the cavitation formulaparameters, and provide theoretical reference for the study of cavitation phenomenon.Based on the numerical simulation, and built the visualization of cavitation testdevice, the digital camera direct photos cavitation, cavitation visualization resultsallows us to observe cavitation more intuitive. Visual experimental results andnumerical simulation results show a high degree of consistency.