Flow-Induced Vibration Test of U-bend Tube Bundle Subjected to Freon Two-Phase Flow (Part 1 : Test Equipment and Partial Measured Results)

摘要

It is one of the most important subjects to estimate the flow-related stability of heat-exchanger tubes at the operating condition. A large size test has been developed for two purposes : (1) to verify the stability of steam-generator tubes in PWR-type nuclear power plants in Japan, and (2) to obtain critical flow velocities of the U-shaped tube array. The U-bend tube array is the same size but a partial model of practical steam generators, and Freon fluid is used to simulate the steam-water two-phase flow. U-bend tubes are combined with so-called "antivibration bar (AVB)s", where two types of AVBs are used. This report shows the outline of the test equipment, and test results of one type of AVBs. Test results show that tubes are stable in up to 150percent of the design flow rate when they are supported as the design requires. Artificially flexible tubes give critical flow velocities, which give an empirical constant to estimate the occurrence of fluidelastic instability.