Method and device for evaluating turbulent vibration of rod-shaped structure of reactor internals

Abstract

The invention discloses a method and device for turbulent excitation evaluation of a rod-shaped structure of internal components. The method obtains flow field parameters and structural parameters of the rod-shaped structure to be evaluated, based on the flow field parameters and structural parameters, and uses a correlation length database through an interpolation method. Obtain the correlation length, select the velocity field from the flow field parameters, and calculate the correlation length and velocity field through the equivalent power spectral density calculation formula to obtain the power spectral density value to be calculated, and put the power spectral density value to be calculated along the Integrate the length direction of the rod-shaped structure to obtain the power spectral density value of the turbulent excitation force curve, analyze and combine the power spectral density values ​​of the turbulent excitation force curve, calculate the vibration response of the rod-shaped structure to be evaluated, and perform post-processing on the vibration response to obtain the evaluation As a result, a suitable stochastic excitation of turbulent vibrations acting on the stack structure can be determined quickly and accurately based on the evaluation results.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor structural mechanics, in particular to a method and device for evaluating turbulent vibration of a rod-shaped structure of a reactor internal component. Background technique [0002] Due to the relatively high fluid velocity in nuclear reactors, there is turbulent flow almost everywhere in the reactor internals, fuel rods, pumps and valves. The turbulent flow will generate pulsating pressure on the surface of the reactor structure flowing through it, and the structure will vibrate under the action of pulsating pressure , this kind of vibration is called turbulent excitation, which is an important cause of fatigue, wear and even failure of reactor internal components. In order to ensure the integrity of the stack structure during its service life, the structural vibration response caused by turbulence can only be controlled within an acceptable range by optimizing the stack structure design...

AI Technical Summary

Problems solved by technology

At present, there are three main methods to obtain the random excitation acting on the stack structure: one is to measure the excitation characteristics such as the pulsating pressure of the fluid acting on the structure through the test, and use the test measurement results as the input excitation to conduct vibration analysis on the structure and calculate the vibration of the structure The advantage of this method is that the calculation results are in good agreement with the test results, but the disadvantage is that the calculation analysis depends on the test; the second is that the time history of the pulsating pressure acting on the structure is obtained through the unsteady analysis of CFD software. The advantage of this method is that it does not depend on Or rely less on experiments. The disadvantage is that CFD unsteady analysis requires a lot of computing time and computing resources. For reactors with complex structures and large geometric scales, it is difficult to strike a balance between computational accuracy and computational efficiency; the third is through The CFD software performs steady analysis to obtain the velocity field and density field of the structure, and combines the dimensionless equivalent power spectral density to determine the fluctuating pressure acting on the structure. The advantage of this method is that compared with unsteady CFD analysis, it consumes more computing resources and The time is greatly reduced, and the difficulty lies in how to convert the dimensionless equivalent power spectral density into the pulsating pressure on the structure

To sum up, the existing methods of stochastic excitation acting on the heap structure are difficult to strike a balance between computational accuracy and computational efficiency

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