Fig. 1 Schematic diagram of the MSUB test rig setup for two-phase flow tests More

Fig. 2 MSUB test rig setup for two-phase flow tests More

Fig. 3 Cross-section of U-tube bundle showing tube numbering scheme and instrumentation layout (units in mm) More

Fig. 4 Photograph of the AVB module installed at support location #1 More

Fig. 5 Photograph of the upstream end of a void fraction probe showing its location relative to the gap between two upper dummy tubes More

Fig. 6 Illustration of the first mode for a middle row U-tube, with the AVBs at locations #1 and #2 not effective More

Fig. 7 Amplitude response of selected U-tubes in the first IP mode versus HEM pitch flow velocity for one AVB support at location #1 for configuration 1. Data point labels indicate the HEM void fraction. More

Fig. 8 Sample vibration response spectra in the IP direction ( a ) and OOP direction ( b ), where the tube bundle is stable in the IP direction More

Fig. 9 Illustration of the third OOP mode shape for a middle row U-tube, assuming ineffective AVB supports More

Fig. 10 Sample vibration response spectra where the tube bundle is fluidelastically unstable in the IP direction More

Fig. 11 Test conditions in two-phase flow and the thresholds for onset and cessation of IP FEI for ( a ) configuration 1 tests and ( b ) configuration 2 tests More

Fig. 12 Sample frequency spectra from configuration 2 damping tests in two-phase flow, with one flexible tube in an otherwise restrained tube bundle More

Fig. 13 Example data for damping ratio measured at comparable flow conditions for configurations 1 and 2 More

Fig. 14 Measured and HEM void fraction for a two-phase flow test in configuration 2 More

Fig. 15 Sample results for work-rate and RMS IP displacement versus HEM pitch flow velocity for ( a ) tube 1B and, ( b ) tube 1D More

Fig. 16 Stability plot for threshold conditions for the cessation of IP FEI for configurations 1 and 2 tests, along with liquid flow and air flow results More

Fig. 1 MSUB test rig More