Research On Wear Characteristics Of High Speed Mixer Blade

Silicon nitride ceramics are widely used in aerospace and military industry,mechanical engineering,communications,electronics,automotive,energy,chemical and biological fields,due to their excellent properties such as high hardness,high strength,corrosion resistance,wear resistance,oxidation resistance,high thermal shock resistance and unique electrical properties.However,the prerequisite for the preparation of highquality silicon nitride ceramics is high-quality silicon nitride powder,which must have the characteristics of pure powder,low impurity content,and high specific surface area.The silicon nitride powder studied in this paper uses a high-speed mixer to de-aggregate the agglomerates of silicon nitride powder synthesized by combustion in the reactor during the preparation process,which will cause blade wear,introduce iron impurities,and reduce the quality of silicon nitride powder.Therefore,in order to reduce blade wear and improve the application performance of silicon nitride powder,according to the controllable parameters of the actual operation of the high-speed mixer,this article uses EDEM simulation software for the agglomeration of silicon nitride powder based on the two factors of the speed of the high-speed mixer and the upper blade angle.Combining the relative wear model to analyze the blade wear of the high-speed mixer,study the influence of different speeds and upper blade angles on the blade wear.At the same time,a test material iron impurity content concentration measurement standard was established to evaluate whether the iron impurity content concentration of the material in the test under the same operating conditions as the simulation meets the standard.And in the case of meeting this measurement standard,the operation parameters of the high-speed mixer are starting to optimize.The research results show that: when the upper blade angle is 15°,corresponding to different speeds of 300r/min,485r/min,670r/min,855r/min,the time required for highspeed mixers equal efficient crush operating shows a trend of first decreasing and then increasing with the increase of speed,the total contact energy of the blades gradually increases with the increase in speed.Considering the crushing efficiency and the total contact energy of the blades,when the blade angle of the high-speed mixer is 15°,the speed is 485r/min,the operation effect is better.When the speed is 485r/min,corresponding to different upper blade angles of 5°,10°,15°,20°,25°,required time and the total contact energy under high-speed mixers equal efficient crush operating show a trend of first decreasing and then increasing with the increase of upper blade angle.Considering the crushing efficiency and the total contact energy of the blades,when the speed of the high-speed mixer is 485r/min,the angle of the upper blade is 15°,and the operation effect is better.The test material iron impurity content concentration measurement standard corresponds to the time required for equal crushing efficiency operation 10.94 s,and the total blade contact energy is 11563.057 J.In the case of meeting the measurement standard,the two factors of the crushing efficiency of the high-speed mixer and the total energy of the blade contact are comprehensively considered to optimize the operating parameters of the high-speed mixer.Set up two sets of simulation experiments: the angle of upper blade is 15°,the speed is 337 r/min,374 r/min,411r/min,448r/min;the speed is 485r/min,the angle of upper blade is 11°,12 °,13°,14°.From the above two sets of simulation results,the parameters optimized for the two factors of the high-speed mixer speed and the upper blade angle are respectively the speed of 448r/min and the upper blade angle of 14°.The two optimized parameters of the high-speed mixer speed and the upper blade angle are selected to simulate the operation of the high-speed mixer.The simulation result under this operating condition is that the time required for the operation with equal crushing efficiency is 9.09 s,and the total blade contact energy is 8744.056 J,which is much smaller than the standard for measuring the concentration of iron impurity content in materials.Based on the above analysis,this paper selects the high-speed mixer speed of 448r/min and the upper blade angle of 14° as the optimization parameters of the high-speed mixer operation combination,which provides a certain guarantee for the actual operation technical guidance of the high-speed mixer and the blade wear protection.