Second harmonic generation-based method for obtaining critical rotation speed of steam turbine rotor

Abstract

The invention provides a second harmonic generation-based method for obtaining the critical rotation speed of a steam turbine rotor, and relates to a method for obtaining the critical rotation speed of the steam turbine rotor, aiming at solving the problem that the existing method for obtaining the critical rotation speed of the steam turbine rotor is large in error between a calculated value and a measured value, and the existing practical detection method is very great in boundedness. The method comprises the following steps of: 1, rising the highest rotation speed of the steam turbine rotor to 1800rpm, and confirming the critical rotation speed position of a second harmonic generation Bode picture in a steam turbine vibration monitoring system; 2, multiplying the value of a first-order critical rotation speed position in the second harmonic generation Bode picture by 2 to obtain the product value which is the first-order critical rotation speed of the steam turbine rotor; and 3, multiplying the value of a second-order critical rotation speed position in the second harmonic generation Bode picture by 2 to obtain the product value which is the second-order critical rotation speed of the steam turbine rotor. The method provided by the invention is used for obtaining the critical rotation speed of the steam turbine rotor.

Description

technical field [0001] The invention relates to a method for obtaining the critical rotational speed of a steam turbine rotor. Background technique [0002] There are two existing methods for obtaining the critical speed of the steam turbine rotor, one is the calculation method, and the other is the actual measurement method. There is always a certain error between the value of the complex boundary conditions such as the support stiffness and oil film stiffness of the actual steam turbine rotor and the actual value by the calculation method, resulting in a large discrepancy between the calculated value and the measured value. The guiding significance of operation and high-speed dynamic balance is not great; although the actual measurement method can accurately measure the critical speed of the rotor, it has great limitations. First of all, when the critical speed is greater than the working speed, the critical speed of the rotor cannot be measured; secondly, in the process ...

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Problems solved by technology

[0004] In order to solve the problem that the existing method for obtaining the critical speed of the steam turbine rotor has a large error between the calculated value and the actual measurement value, and the actual measurement method has great limitations, a method for obtaining the critical speed of the steam turbine rotor based on double frequency is proposed.

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