| In recent years, with the rapid development of our national economy, the demandfor electricity is increasing. It is urgent that the generator should have a larger capacityand a higher power generation. Retaining ring of the motor is an important part of thegenerator. When the generator functions properly, the retaining ring suffers a alternatingpressure from the rotor and a huge centrifugal force when the two are rotating.Therefore, the requirement is especially harsh of the mechanical properties of retainingrings and its assembly with the rotor. The austenitic antimagnetic steel retaining ring onactive service has a huge weight, depends on imports.All these restricts our contury’sindependent development of the large capacity generator. At the same time, theapplication of carbon fiber reinforced composites (CFRP) is more and more mature andwidely in engineering, for its high specific strength and high specific modulus, lowpermeability, easy molding and low cost. When the composite retaining ring applys asthe engineering structure, in order to meet the requirements of assembly and precision,it is need to machine the materials. The retaining ring and the rotor is in interference fit,a reasonable assembly between them is of great significance for the normal operation ofthe rotor.In view of the above problems, this paper designed and manufactured the retainingring of carbon fiber composite material of600MW turbine generator. First, chosen thecomposite system, such as the reinforced fiber, resin matrix, curing agent, accelerator,and determined the preparation process and layer design. Secondly, machined thecomposites, and tested the roughness of machined surface, which optimized the cuttingparameters. Furthermore, the thermal expansion coefficient and the deformation of thecomposite retaining ring was experimented and simulated, finally designed thesimilarity of different scale composite materials, finally carried out the compositeretaining ring and the rotor’s assembly simulation, which was a preparatory work for theassembly of the outer ring and the rotor.This paper simulated the following two aspects of the composites with finiteelement software:1) The method of interference fit between the rotor and the retaining ring iscombined with hot charging method and cold charging method. In order to ensure theassembly experiment conduct smoothly, this paper simulated the radial shrinkage of therotor at low temperatures, and the expansion volume of the retaining ring’s radial surface at high temperatures. Simulation results show that: for600MWe turbinegenerator retaining ring prototype of carbon fiber composite material(To reduce theproportion of4:1), whose radial expansion ratio is0.0447mm at120℃, and radialshrinkage of rotor is0.681mm at-110℃. This paper also simulated the glass fiber andcarbon fiber reinforced composite’s heat expansion at high temperatures. Results showthat, the radial heat expansion of glass fiber composite retaining ring is amount to0.389mm at120℃, which is9times greater than that of carbon fiber compositeretaining ring.2) Between the retaining ring and the rotor interference fit has a great influence onthe stress both work, this paper simulates the rotor and the retaining ring assemblyinterference after the stress distribution, based on the analysis of stress distribution onthe contact surface. The results showed that, when the amount of the interferenceassembly was0.3mm, the inner boundary of the stress can reach20.42MPa,which wasless than the CFRP’s longitudinal compression strength,900MPa. When Retaining ringwas rotating at the frequency of50Hz, the maximal circumferential expansiondisplacement was about0.05mm.When rotating at60Hz, which is the limit frequency,the maximum expansion displacement of the ring was about0.075mm.This expansionwas in the the range of the interference fit design volume of the retaining ring and therotor.Therefore, it will not affect the overall cooperation between the rotor and theretaining ring. |
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