Design And Research On Pneumatic Collection Device Of Particle Group

In special environments,collecting particles in deep wells is a relatively complex problem.Under this working condition,pneumatic collection device has great advantages over mechanical collection device.The pneumatic collection device is smaller and more flexible.When necessary,flexible pipes can be used to adapt to complex environments.In this paper,a pneumatic collection device for particle groups was designed,and the performance of the executive part was tested and simulated,which provides reference for future researchers to solve similar problems.In this paper,firstly the overall scheme of the particle group pneumatic collection device was designed.The author investigated the mechanical behavior of the particles under the suction flow field.The particle collection process can be divided into three stages: starting,lifting,and separating.According to the characteristics of the geometric space inside the deep well,the vacuum generator and the cyclone separator were used as the main executive components,which can greatly reduce the volume of the device and make it have better installation manufacturability.Secondly,the force analysis of the particles was carried out,the dynamic equation of single spherical particles was established,and the relationship between the suspension speed and the particle size and density during vertical lifting was calculated.Based on this,the vacuum generator was designed as the suction device of the actuator,and the parameters were refined.The dynamic equation of the centrifugal sedimentation of particles in the cyclone field was established,and two different types of cyclones were designed to separate the particle group.Based on the description method of cylindrical coordinates,a kind of three-degree-of-freedom moving device of R-axis,Xaxis and Z-axis was used to control the precise positioning of downhole components.Then,a particle group suction test platform was built to test the performance of the collection device.The flow characteristics of the vacuum generator were calibrated,and the pressure loss coefficients of the two cyclones were also obtained.Glass balls and quartz sand were used as the suction materials,and the accumulation characteristics were obtained in the experiment.The separation efficiency of the cyclone separator was tested,and it was found that the separation performance of the tangential inlet cyclone separator was better than that of the axial vortex tube separator.It is observed that the solid phase interface with concave on both sides,gentle in the middle or slightly convex in the suction flow field is formed by suction test on the particle group.The mass change of the particle group was recorded and used as the following text the basis for verifying the credibility of the simulation.Finally,a CFD-DEM coupling simulation was performed on the particle collection process,and the outcomes are compared with the experimental results.The separation simulation results showed that the reason for the lower separation efficiency of the axial vortex tube separator was the impact of the collision between the particles and the wall and the particles on the motion state.The suction simulation obtained the solid-phase interface of the particle group,combined with the initial flow field,the formation mechanism of the particle saltation and the solid-phase interface were analyzed.The above conclusions provide a basis for the further optimization of the entire device in the future.