| Gas-solid two-phase flow centrifugal fans are widely used in power and energy, powder and combustion, green dust filtering, aeronautic and many other industries. When the fluid containing solid particles as the working media through the impeller, solid particles will inevitably impact, friction, and wear, rebound with the blade and accumulation will also be formed on the impeller, these actions are harmful to balance of impellers and can reduce its using-time. At the same time, erosion will occur because the solid particles in the fluid can impact with blade, which result in friction failure of impeller. According to fan industry association statistics of China,40%of fans is conveying gas-solid two-phase mixture type. So, it is very important for researching the wear problems of gas-solid two-phase flow fans.Firstly, the wear mechanism of gas-solid two-phase flow centrifugal fans blade is described in this paper. And then relative advanced methods are also studied through introducing the flow field generated in centrifugal fans and how that flow field changes through the downstream stator vane. By means of Optical microscope, Scanning Electron Microscope, X ray diffraction, Coating thickness gauge and so on, this paper is systematically researching the influence on the structural design, the blade material selection, the Micro arc oxidation process of the centrifugal fan operating under particulate flows have on the wearing and time-using of the blade. It makes a discussion on the wear mechanism and antifriction way of the blade of the centrifugal fan operating under particulate flows, gaining the following innovative research results:(1) Through the comprehensive innovation design of the structure of the centrifugal fan, the gas flow field of spin is generated when the impeller is rotating in high speed, then the gas flow field completes the energy transfer, making most of the fluid pass through the impeller, to reduce the energy losses and the collision, the friction, the wearing of the solid particles on the impeller to prolong the using-time of the impeller. The test results show that the resistance of the new centrifugal fan blade is about four times than that of the traditional fan. (2) Through optimizing properly matched blade material and the simple heat treatment process in place of the commonly used low carbon structural steel, the aim of improving performance and reducing wearing and cost is achieved. The test results show that Quenching and Tempering treated40Cr steel and45steel can replace the commonly used blade material Q235(A3steel) and Q345(16Mn steel), which can increase the wearing resistance of the blade and improve using-time of the impeller.(3) Taking the4A01Aluminum alloy as the research object, a layer of compact MAO coating on the Aluminum blade is formed through micro-arc oxidation process, which can improve the blade wear resistance, corrosion resistance, prolong using-time of the impeller. The effect of different electrolyte concentration on the striking voltage, thickness of MAO coatings, surface morphology, phase composition, wear-resisting performance is researched. The test results show that the electrolyte is Na2SiO3+KOH+H3BO3+C3H8O3, and when the concentration of Na2Si03is12g/L or so, the wear resistance of MAO coating is the best. The effect of the voltage, current density on the thickness of MAO coatings, surface morphology and phase composition and the wear-resisting performance is researched. The test results show that when the forward voltage is450V or so and forward current density is12A/dm2or so, the wear resistance of MAO coating is the best. |
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