Method for determining critical rotating speed of wet rotor of multistage centrifugal pump

Abstract

The invention provides a method for determining the critical rotating speed of a wet rotor of a multistage centrifugal pump. According to the method, an automatic node division module, a model creating module and a model calculation module are mainly utilized for determining the critical rotating speed, and the data processing is carried out among the modules in a sequence sequentially from the automatic node division module, the model creating module and the model calculation module. Firstly, the automatic node division module creates a geometrical model of a wet rotor system on the basis of an engineering drawing, and in addition, the automatic division of modes is carried out; secondly, the model creating module is utilized for inputting physical parameters of parts such as rotating shafts, impellers, bearings and sealing clearances, and a total mass matrix [M], a total rigidity matrix [K], a total damping matrix [C] and an overall calculation model of a multistage centrifugal pump shaft system are built; finally, the model calculation module is utilized for solving the overall calculation model of the multistage centrifugal pump shaft system, a Campbell chart is drawn, and the required first n step of critical rotating speed is obtained. The method has the advantages that the operation is simple, the engineering applicability is wide, the critical rotating speed of the wet rotor of the multistage centrifugal pump can be calculated under the condition of different structures, the engineering design and the application of the rotor of the multistage centrifugal pump are guided, the design period is shortened, and the production efficiency of the rotor of the multistage centrifugal pump is improved.

Description

Technical field [0001] The present invention relates to the field of multi-stage centrifugal pump rotor design. More specifically, the present invention relates to a method for determining the critical speed of a wet rotor of a multi-stage centrifugal pump. Background technique [0002] Multi-stage centrifugal pumps are widely used in the fields of chemical, petroleum and electric power. Multi-stage centrifugal pumps are developing in the direction of large-scale and high-speed. The number of impellers is increasing, and the stability of unit operation is becoming more and more important. In the design and research of rotor dynamics of multi-stage centrifugal pumps, the critical speed is a very important concept and parameter in rotating machinery. When the multi-stage centrifugal pump is working near the critical speed, the amount of shaft deflection increases significantly and the gap between the seal It will cause serious friction and friction with the shell parts, and the vib...

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Problems solved by technology

[0004] At present, the calculation of the critical speed of the multistage centrifugal pump shafting in domestic engineering is mainly for the case of dry rotors. The multistage centrifugal pump shafting is modeled and the critical speed is solved by finite element software such as ANSYS and ADAMS. For the multistage impeller 1. Multistage centrifugal pumps with long shafts need a long time from modeling to obtaining results, and the wet rotor effect of the pump shaft is often not considered in the modeling, resulting in a large discrepancy between the calculated value and the actual situation, and the above finite element software Operators with certain professional qualities are required to operate, the production efficiency is low, and it cannot be widely used in engineering. It is used to guide the engineering design and production of multi-stage centrifugal pump rotors. At this stage, there is a lack of wet rotors suitable for multi-stage centrifugal pumps in engineering. Guidance method and platform for critical speed calculation

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