STUDY ON FLOW INDUCED VIBRATION ANALYSIS AND EVALUATION FOR HEAT TRANSFER TUBE OF STEAM GENERATOR IN TWO PHASE FLOW

摘要

The flow induced vibration of heat transfer tube is one of the main factors leading to the failure of heat transfer tube in steam generator, the flow induced vibration of steam generator should be analyzed and evaluated in the design of steam generation. The flow induced vibration of heat transfer tube in two phase flow is the difficult and important content in the analysis. In this paper, the finite element model of heat transfer tube is established and the modal analysis is carried out. Then in order to evaluate the influence of two phase flow in the secondary side and support boundary constraint, the analytical results are compared with the natural frequency of the heat transfer tube measured in the two phase flow test. On the basis of accurate simulation of the dynamic characteristics of heat transfer tube in two phase flow, the paper calculate the turbulent excitation response and the fluid-elastic instability ratio aiming at the main mechanism causing the flow induced vibration of heat transfer tube in two phase flow. The modified PSD of turbulent excitation is proposed on the foundation of root mean square displacement amplitude of heat transfer tube measured in two phase flow test. The calculation result of the amplitude of heat transfer tube with different void fraction can envelope the test result by using the modified PSD as input, and the safety margin is reasonable. We also verify whether the analysis conclusion of fluid-elastic instability is in agreement with the test. The paper studies on flow induced vibration analysis and evaluation for heat transfer tube of steam generator in two phase flow, modifies the analysis program of flow induced vibration on the basis of the test results, the investigation can be used at the risk prediction and evaluation of flow induced vibration of heat transfer tube in two phase flow, solve the technical difficulties of flow induced vibration analysis in two phase flow, provide the technical support for the flow induced vibration analysis of steam generator in Hualong one.