| With the rapid development of the air separation unit manufacturing industry, the market share of homemade air separation unit rises year by year. However, due to the low operational reliability of domestic large-scale air separation unit, whose life cycle accounted the short life cycle which accounts only 1/2-2/3 of the machine made abroad, as well as the high rate of domestic equipment failure, serious worksite accidents occur frequently. Therefore, the operation stability of complex air separation type of complete sets of equipment has become an urgent research issue that needs to address.This thesis bases on the study of a type of a large-scale air compressor's low-pressure end section which consists of low pressure cylinder, intermediate pressure cylinder, turbine, tooth booster, impellers and other components and parts. Founded on analyzing dynamic characteristic of the unit shaft system, the synchronous operation stability of the shaft system is studied. A new technique method that could decrease the failure rate and increase the operational reliability called-Dynamic Matching Technology is proposed. The investigation processes in detail are as follows.The technological process of the equipment is analyzed, based on which, we use MATLAB to simulate to get the change law of the compressor sets state parameter when the machine is in steady operation.Through the analysis of shaft system's load and force, we discuss the influence of the change of compressor sets' state parameter on shaft system's load and force. Shaft system's 3D model is built by Pro/E to lead to ANSYS to load process and finite element unit division to get the finite element model.The shaft system's modal is analyzed with finite element method to obtain the critical speed of rotation of former 20 orders and vibration mode figure of former 6 orders. The shaft system's structure of vibrated shape and weak part is denitrified by the working above. Get the amplitude-frequency response of each shaft section by means of unbalance response analysis of each shaft section so as to learn that the motivation exerted on the intermediate pressure cylinder has the maximum influence at the working speed. After classifying and summarizing and summarize the shaft system's reliability analyzing target. This thesis finds out the main factors that affect the machine shaft system's operational reliability.Use Box-Counting principle and square method to conduct curve fitting to obtain the orbit (0.5653) of shaft center's stability indices of steam turbine shaft section. Use Routh Criterion to prove the shaft section the oil film system steady after getting the Rous array. Get the elevation and load of each bearing using the method of transfer matrix with MATLAB to solve equations. According to the principle that the sum of shafting clutch and shearing force equal to zero, we get Yang curve of shafting. The logarithmic decrement of each shaft section is above zero and the minimum is 0.202 which means shafting has enough stability margins after getting the former 6 orders' logarithmic decrement of the machine shafting. Match the dynamic characteristics of multicomputer shafting. Improve the structure's dynamic response and enhance the stability of the machine shafting through adjusting the machine shafting's structure to change its critical speed of rotation and mode of vibration. Manish fault response and lower fault sensitivity through the anti-fault mate of the machine shafting. |
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