Design And Research On Circular Arc Separating Device Of New Hammer Mill

At present,hammer mill is widely used in feed processing in China.In view of the problems of low screening efficiency,serious energy consumption waste and large material temperature rise of the traditional hammer mill,the research group has developed a new hammer mill that can realize the circular crushing process on a single machine.The preliminary research shows that the crusher can effectively solve the problems of over crushing and large temperature rise of materials,but there is still the problem of low separation efficiency compared with crushing efficiency,which can not effectively reduce the energy consumption of the whole machine.Therefore,this thesis aims to improve the material conveying capacity of the separation device,and then increase the discharge volume,so as to improve the productivity of the crusher.A circular arc separation device is designed,and the motion law of materials in the circular arc separation device is studied by using the method of numerical simulation and experiment.The main contents and conclusions are as follows:(1)Based on the hydrodynamics software Fluent,the single-phase gas flow field in the crusher is numerically simulated,and the velocity distribution and pressure distribution of the gas flow in the new and old separation devices are compared and analyzed.The results show that the circular arc separation device can effectively improve the velocity and pressure of the gas flow compared with the original separation device,contribute to the transportation of materials,and then increase the discharge volume;Based on the equal area method,the wind speed at the outlet of the crusher is tested,and the error between the test results and the simulation results is analyzed.The results show that it is feasible to simulate the single-phase flow of air flow in the crusher with Fluent.(2)Based on the Fluent-EDEM coupling method,the gas-solid two-phase flow field in the old and new separation devices is numerically simulated,and the motion law of particles in the two separation devices is compared and analyzed.The results show that the circular arc separation device can effectively reduce the collision between particles and wall,reduce the energy loss of particles,and then improve the discharge;The results show that it is feasible to use Fluent-EDEM coupling to simulate the gas-solid two-phase flow in the separation device;Based on the Fluent-EDEM coupling,the single factor simulation test of the two separation devices is carried out.The results show that the discharge volume of the circular arc separation device increases with the increase of the inlet air flow velocity and the inlet material flow velocity,and decreases with the increase of the outlet negative pressure and particle size of the return pipe.(3)The single factor comminution test was carried out on the pulverizers with old and new separation devices,and the effects of spindle speed and feeding rate on productivity were compared and analyzed.The results showed that the productivity of the pulverizer with circular arc separation device increased with the increase of spindle speed,and the feeding rate increased first and then decreased;There is an extreme point of spindle speed.Compared with the original separation device,the structural characteristic advantage of circular arc separation device can reach the most significant;The greater the feeding rate,the more obvious the structural advantage of the circular arc separation device.The research of this thesis can provide theoretical basis for the design of new hammer mill,and has certain practical significance for promoting the technological progress of feed crusher industry.