| Working face support is the primary condition for safe and efficient comprehensive mining in coal mines.Hydraulic support is the core of a comprehensive mining system and major equipment for coal mining.High water-based backwash filter is widely used in the hydraulic system of fully-mechanized coal mining support,which is used to filter the particulates contained in the emulsion and achieve self-cleaning.It is the key factor to ensure the safe and efficient production of the fully-mechanized coal mining face.Here,the hydraulic scaffold backwash filter is taken as the research object,and the virtual dynamic technology is used to realize the visual dynamic observation of the filtration state and the backwash state close to the actual fluid motion trajectory.From the filter element-cake backwash dynamic erosion,the filter element-cake coupling vibration,the dynamic simulation of the built-in spool filter flow field,and other aspects have been studied on the dynamic characteristics of the backwash filter and the peeling mechanism of the filter cake,further improving the filtration efficiency and backwash effect,reducing the cost of backwash filter development and reducing the design cycle.Firstly,the virtual reality technology was applied to the research of the hydraulic support filtering system.The three-dimensional model of the filtration system was established,and the virtual reality software program was compiled to simulate the fluid trajectory and element movement in the filtration system.The keyboard and mouse were used to simulate the manual operation control or program control of hydraulic components(reversing valve,check valve,etc.)to realize human-machine environment interaction,so that the fluid dynamically flows in a predetermined trajectory in the filtration system,and the elements such as the filter element achieve dynamic operation.Secondly,the dynamic erosion and surface morphology of the filter element-cake backwash were studied,and a simulation method of peeling the filter cake layer of the backwash filter was proposed.The coalescence mechanism of the particles in the filter cake was simplified.Coal-fine sandstone flexible surface of spherical material particles was used as a model for the filter cake layer.High-pressure water droplets with different impact speeds and angles were used to simulate the peeling of the filter cake.The surface morphology of the filter cake under different impact angles was analyzed.The simulation results show that the filter cake weight loss rate and the number of broken bonds take their peaks near the impact speed of 90m/s and the impact angle of 30 °;by adding the 23 °,24 °,and 25 ° groups between 20 ° and 30 ° impact angles,the simulation shows that the weight loss rate and the number of broken bonds of the filter cake peak at an impact angle of 24 °.Finally,the optimal impact angle of the backwash dynamic erosion filter cake is determined to be 24 °.The coupling vibration characteristics of filter element-cake were studied again,a backwashing method for high water-based filters based on fluid-structure coupling resonance was proposed,the basic equations for fluid-structure coupling system analysis were established,and harmonious analysis was performed through modal analysis under prestress in response analysis,the influence of the water jet target distance on the full coverage filter cake and the random distribution cake peeling was studied,and the strength of the filter was verified.The simulation results show that the maximum pressure value on the filter cake surface is 1.2 MPa;the resonance response values of the filter element and the filter cake in x direction and y direction are significantly larger than those in z direction;the optimal water jet target distance obtained by the simulation is 5.47 mm,and the filter element-cake resonance response value is the largest;the maximum peak response frequencies are 27 Hz and 31.5Hz,corresponding to the natural frequency of the first-order mode under two conditions;under the premise of ensuring the strength of the filter element,the filter element-cake has a good vibration state,and the large vibration deformation can accelerate the speed of the filter cake off the surface of the filter element.Finally,the dynamic mesh technology was used to simulate the closing process of the built-in spool,and the pressure field and velocity field distribution of different spool opening degrees when the response times were 0.2s,0.5s,1.23 s,and 2s are analyzed,and drew steady-state hydrodynamic curves to compare the difference between the simulated value curve and the theoretical value curve.The results show that when the spool response time are 0.2s and 0.5s,the pressure of the fluid impacting the spool can be quickly established,but the smaller spring stiffness makes the spool reset process slower;when the spool response time is 2s,the spool moves to close the liquid flow takes a long time,causing the pressure of the backwash liquid flowing through the U-shaped tube to impact the filter element-cake to be low;while the response time of the spool is 1.23 s,which will not affect the normal filtration of the filter due to the short response time,nor extend the filter backwashing time because of the long response time,which is the best spool response time.In this paper,a virtual reality simulation of the high water-based backwash filter system,dynamic erosion of filter element-cake backwash,research on the characteristics of filter element-cake coupling vibration,and dynamic simulation analysis of the flow field of the built-in spool filter are performed.Optimization,cleaning without blind spots control,quality controllability and product display are of great significance. |
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