An Experimental Study On Fluctuating Pressure Characteristics Of Self-excited Inspirarory Pulsed Jet

The present situation of our country distribution of river and reservoir sediment resulted in reservoir dredging has become an urgent problem.Self-excited pulsed jet with output energy cycle,there was the periodic fluctuation with the jet pressure between the maximum and the minimum.Then,the water sediment by momentum greatly formed in a very short period of time,the relaxation effect of the erosion deposit was improved.The work efficiency was improved due to the stirring effect and free turbulent jet entrainment of bottom sediment.The self-excited pulsed jet in recent years has been gradually applied to deepwater reservoir bottom sediment dredging work.For the destruction of the pulsed jet,the pressure characteristics and the pulsation characteristics of the pressure pulse were determined Therefore,this paper studied on the fluctuation of the pulse jet impact pressure on the self-excited inspiratory.The first chapter briefly introduced the characteristics of several new jets.The research situation of the research and application of the self excited oscillation pulsed jet is summarized.There were the researches on the pulse pressure of the jet in recent years.The application of high speed imaging technology and used the researches of two phase flow was briefly introduced.The second chapter introduced characteristics of submerged jet the classification of water jet,the basic structure and characteristics of submerged jets.The generation mechanism of the self excited oscillation pulsed jet and the self excited inspiratory pulsed jet were analyzed.The factors of the two jet impact force and a brief description of the qualitative influence the performances were studied.Finally,the statistical analysis method of the pulse pressure signal is introduced.In the third chapter,the research was carried out on the self designed self excited pulsed jet nozzle under the submerged environment.Firstly,the statistical characteristics of the pulsed pressure signal of the self excited pulsed jet are analyzed.And then,The radial distribution of the self excited pulsed jet and the self excited pulsed jet were compared and analyzed.The influence of different parameters on the pulse pressure characteristics of self excited inspiratory pulse jet was systematically analyzed by the three statistical features(Pressure fluctuation,the time of pressure,and fluctuating pressure mean square deviation,that is,the peak value of fluctuating intensity).The fourth chapter won the one complete cycle of oscillation oscillation cavity flow change process and verified the self suction pulse jet is a periodic change,research on the flow pattern of self excited pulsed jet nozzle oscillation cavity by high speed imaging technology and image processing technology.The influence of different parameters on the flow state of the oscillating cavity of the self excited inspiratory pulse jet nozzle was analyzed,and the influence of different parameters on the pulse pressure characteristics of self excited inspiratory pulse jet was verified by mutual validation.There provided theoretical and technical basis for the application of the device.The fifth chapter was the conclusion and outlook for the full text.