Research On Cavitation Mechanism And Noise Characteristics Of Ecowirl Cavitator

Hydrodynamic cavitation is a very complex physical phenomenon.When the fluid passes through a sharp change cross section,it will produce pressure drop.At this time,the gas in the liquid will be separated from the liquid and vaporize to form cavitation bubbles.Different from other cavitation types,hydraulic cavitation is more easily controlled,more convenient,more efficient and easier to produce cavitation,which makes hydraulic cavitation more suitable for industrial application.Venturi tube and orifice plate are the most widely studied hydrodynamic cavitation devices.But the cavitation effect between them needs to be improved.In 2015,Michela Langone et al.proposed a new type of hydrodynamic cavitation generator(Ecowirl),which is based on a specific geometric structure to form a multidimensional vortex.This structure makes the Ecowirl cavitation device form stronger cavitation effect.In this paper,the CFD numerical simulation method is used to simulate the cavitation flow field of the Ecowirl cavitation device under different structures.The cavitation effect can be improved by optimizing the structure of the Ecowirl cavitation device.The hydrodynamic noise and cavitation noise in Ecowirl cavitation are analyzed.And the specific research results are as follows:1.With the help of the finite element software Fluent,the numerical simulation of the cavitation flow field of the Ecowirl cavitation device under different structural dimensions is carried out under the condition that the remaining parameters are consistent.The result shows that the cavitation effect reaches the best while the expansion angle is 40°(a =40°).2.Cavitation mainly occurs in double cone chambers,so numerical simulations for Ecowirl cavitation under different conical chamber structures are carried out.It is found that the cavitation intensity decreases with the increase of L.And the cavitation scope is decreasing.This result is consistent with the experimental results of Giuseppe Mancuso et al.3.We made a preliminary analysis of hydrodynamic noise and cavitation noise in Ecowirl cavitation device.Our result indicates that there are many sound pressure pulse signals in the sound pressure fluctuation diagram,which are the cavitation noise caused by the collapse of cavitation bubbles.4.The cavitation noise at different entry pressures is monitored,and it is found that with the increase of inlet pressure,the cavitation range of Ecowirl cavitation increases,and the cavitation intensity increases.At this time,there will be more acoustic pressure pulse signals monitored by the cavitation noise,and the amplitude of acoustic pressure will also increase with the enhancement of cavitation intensity.