Optimization Of Damping Force Model And Impressed Force Model Of Water Flow Vibration Equation In Jigging Machine

This article takes flexible air chamber jigger as subject and studied how the impressed force — the wind pressure changes with time at different control parameters,such as intake and expansion period,emission period.After theoretically analyzing the rise process of liquid level,the author derived the computational formula of the power done by the impressed force and amplitude of water flow as well as the energy dissipation.Besides the article analyzed several main forms of energy dissipation during the rise process of water flow.At last,the experimental study was conducted to study the resistance effects of different density,particle size and volume of the bed on the water flow and confirmed with the energy dissipation model.The author mainly studied how the intake period,expansion period and exhaust period affect the wind pressure.After a large number of mapping analysis,the authors summarized three characteristics from the wind pressure change images based on the statistical law.The wind pressure rises to the maximum in one sampling time at the early stage of the intake period,and the wind pressure sees a decrease at first and then rise slightly to the initial level during the intake and expansion periods.When the exhaust period starts,the wind pressure would experience a sharp drop in one sampling time to a low level.So the author made two assumptions as follows.The wind pressure changed linearly during one sampling time at the start of intake period and exhaust period.And the wind pressure changes sonically with time during the intake and expansion period.Finally,the model fit well with the experimental data.In this paper,the jigger level amplitude model is established by abstract theory analysis.After theoretical analysis,the author obtained the relationship between external force works,liquid level amplitude and energy dissipation.The energy loss related to the particle bed come from three aspects.The first is the viscous force of the particle surface and the water flow.The second is the large amount of energy loss caused by collision between particle and particle.The third is the kinetic energy owned by the particle bed when the vibration system reaches its maximum amplitude.The energy dissipation theory can systematically explain the influence of different bed conditions on the liquid level amplitude.After deriving the liquid level amplitude model,it is concluded that the externalwind pressure increases and the liquid level amplitude increases proportionally.This conclusion is consistent with the actual experimental results,so the model was confirmed.It can be seen that the liquid level amplitude is inversely proportional to the energy dissipation from the amplitude mode established.Therefore,the obstruction of the bed to the water flow can be characterized by the liquid level amplitude.The author studied the effects of bed thickness,bed density and particle size on the pulsating flow resistance.After the experiment,the following three conclusions are drawn.(1)With the increase of the thickness,the liquid level shows a tendency to decrease first and then increase.The increase of the thickness leads to the increase of the viscous force between the particles and the water flow,the collision increases,so the energy dissipation increases;when the thickness increases to a certain extent,,the bed particles contain less kinetic energy,the viscous force become dominant,the liquid level began to increase.(2)As the bed density increases,the maximum amplitude of the liquid level decreases as the bed can jump.This is due to that the energy dissipation brought by particle collision increases with the density of particle;when the bed can not jump,the collision as well as the energy in the form of particle kinetic energy all decrease,so the amplitude of the liquid level increases.(3)The smaller the size of the bed,the greater the damping effect will be.When the size of the bed decreases while the total volume keep unchanged,the specific surface area of the bed will increase.Thus,the energy consumption caused by the collision and viscosity will increase.Then,the amplitude of the liquid decreases as the particle size decreases.