Shell Side Water Flow Test on FBR IHX Tube Bundle

Abstract

In order to study the problem of the compactness in IHX (intermediate heat exchanger) tube bundles for FBRs (fast breeder reactors), several water flow experiments were conducted using a full-size model of a 30 degrees IHX tube bundle sector. The tube bundle comprised thin-wall tubes of small diameter arranged in triangular array at a pitch-to-diameter ratio of 1.25. In the present paper, results of flow induced vibration tests are discussed. To investigate tube vibration characteristics, strain gages were attached to the inner walls of nine tubes in the bundle. In the experiments, no fluidelastic vibration was found up to a flow rate of 120%. However, buffeting effects were observed. The amplitude of these vibrations towards the center of the tube bundle was larger than on the periphery, but the levels observed were low. Vibrations induced by vortex shedding were also seen over a limited area of the inlet region, however the level of vibration was negligible.