According to a large number of experimental results and combined with micro-cutting theory, when the incident angle of particles is about 20b~30b, the typical plastic material erosion rate reaches the maximum. The power plant fan impeller generally adopts ordinary low alloy 16Mn steel, which is a typical plastic material. The induced draft fan of the Shengli Power Plant, the original designed back-bend impeller, mainly considers the blade installation angle of 45b from the viewpoint of improving efficiency. The incident angle of the dust particles does not avoid the range of 20b~30b during operation, and the impeller also It is determined that it is in a state that is most susceptible to wear, as evidenced by the severe wear of the impeller in actual use. The incident angle is lighter for brittle materials. When the blade working surface is covered with brittle materials (such as FeO5, ceramics, etc.), the wear of the brittle material is much lower than that of the parent metal 16Mn steel, which is also consistent with Theoretical analysis above. According to the micro-cutting theory of Professor Finnie of the University of California, USA: W=MU21pf(A) where: W is the volume lost by the target, M is the total mass U of the erosion particle beam is the incident velocity of the particle, and p is the plastic flow stress of the target. A is the incident angle of the particles. It can be seen from the equation that the mass of the particles is proportional to the amount of wear, and the concentration of the particles determines the mass of the particles in the particle beam. Therefore, the concentration of the particles is proportional to the amount of wear. The incident angle of particles is a very important parameter. The amount of wear varies with the angle of incidence. When the angle of incidence is less than a certain critical angle, the erosion rate or erosion volume of the target increases with the incident angle. Increase; but when the incident angle is greater than the critical angle, the change of the erosion rate and the incident angle of the target follows another rule, that is, gradually decreases as the incident angle increases. The copper, low carbon steel and aluminum materials were used as targets. When the incident angle was about 20b, the maximum erosion rate of all three materials occurred. From this analysis, when we use plastic materials as targets, the angle of incidence of erosion should be avoided as much as possible around 20b. The analysis of the incident angle is for the case where the target material is a plastic material, and the plastic material is a brittle material (such as ceramics, glass, etc.), and the erosion rate of the brittle material is completely different from the plastic material with the change of the incident angle, and the brittleness is different. The maximum erosion rate of the material occurs at an angle of incidence close to 90b. According to the micro-machining theory, the high concentration of flue gas will cause serious wear on the impeller. Thus, due to the extremely uneven distribution of the dust particle concentration, the impeller wear is extremely uneven. The facts prove that the Finnie micro-cutting according to the above analysis. Theoretical and a large number of experimental results show that the erosion rate of the material is closely related to the incident angle of the particles. According to a large number of experimental results and combined with micro-cutting theory, the typical plastic material erosion rate reaches a maximum when the incident angle of the particles is about 20b-30b. The efficiency of the fan we are talking about is the full-pressure efficiency of the fan. From the point of full-pressure efficiency, the actual efficiency of the fan is reduced, and the power generation load of the power plant is changed. The load of the fan must change, and it cannot be operated at high efficiency. In addition, the application of the sawtooth center plate reduces the weight of the fan in the middle of the fan, and the overall efficiency of the new impeller is not much different in actual use. Automatic Heat Sealing Shrink Packing Machine Auto Sealing and Shrink Tunnel Packing Machine with PLC Shrink Packing Machine,Automatic Heat Sealing Shrink Packing Machine,Side Sealing Shrink Packing Machine,Automatic Side Sealing Shrink Packing Machine Hangzhou Xiaoshan Wanfeng Mechanical & Electrical Equipment Factory , https://www.wfengmachinery.com
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