Study On The Hydraulic And Climbing Vibration Characteristics Of Hydrodynamic Closing Of Emergency Gate

In the closing process of moving water,its hydrodynamic characteristics are very complex due to a variety of factors.And improper design of the bottom edge,the adverse flow conditions or irrational support structure will affect the normal operation of the gate,cause violent vibration of the door,even with a large amplitude of climbing phenomenon,which will make hit shock load of the crane,adverse to the opening and closing device and gate operation.At present,there are two aspects about the main factors that cause climbing phenomenon: friction or pulsation pressure,but there is no definite conclusion.The relevant experimental research was rare.Taking the emergency gate as the research object,this paper mainly studied the effect of parameters such as the shape of sluice bottom,gate head and gate opening on the hydraulic characteristics of gate;Combined with the existing research results on the phenomenon of climbing vibration,we take the closed-door holding force and the vibration acceleration as the measuring indexes of the gate vibration to explore the influence of gate bottom rim patterns、the opening rate of main beam、supporting structure、working parameters and gate weight on crawling vibration.The main results are as follows:(1)The time-frequency analysis method of random vibration response of structure is introduced-wavelet transform.And the method of removing impulsive and trend term based on wavelet transform is explained and summarized.The main idea and its advantages and disadvantages are analyzed.At the same time,the time-frequency analysis method based on wavelet technology is introduced in detail,which lays the foundation for the subsequent non-stationary signal processing.(2)Based on the Maerdang physical model,the fluctuant pressure characteristics of the door body in the process of closing door with different bottom body type accidents are studied.Using the EMD method,comprehensive explore the influence of the position of measuring point,the upstream water level and working opening on the measuring point pressure.And the point pressure pulsation characteristics,pulsating pressure spectrum characteristics and negative pressure characteristics are analyzed.Then the bottom edge pressure distribution characteristics of the three kinds of bottom-edge sluice gates are compared and analyzed.Result shows: The pulsation intensity basically increases with the increase of the upstream water level and the opening of the working door;meanwhile,the change of gate bottom rim patterns has a significant effect on the holding force.During the closing process,three kinds of bottom edge type accident gate did not show any negative pressure at the bottom edge which showed the upward force and was harmful to the accident gate.(3)The relations between climbing vibration and various parameters,such as the gate bottom rim patterns、the opening rate of main beam、supporting structure、working parameters、gate weight and gate support material,are studied systematically for the first time.Result shows: Changing the gate bottom rim patterns and the opening ratio of main beam to some extent improved the climbing phenomenon,but it is not a qualitative factor.Change the form of gate movement or gate support material which means reducing the friction coefficient of the support structure can inhibit the gate vibration,improve or eliminate the phenomenon of gate vibration.So,we should choose a suitable support structure combined with the actual project situation in the gate design process.Meanwhile,increasing the gate weight,lowering the water level and opening ratio are conducive to closing the gate.