Fluid-Elastic Instability of Rotated Square Array Tube Bundle in Two-Phase Cross-Flow

摘要

Fluid-elastic instability in air-water two-phase cross-flow has been experimentally investigated using two different arrays of straight tube bundles. Rotated triangular array tube bundle with p/d of 1.47 is for the counterpart test of existing work. Rotated square array tube bundle with p/d of 1.633 is for the investigation of fluid-elastic instability in KSNP steam generator. The present paper provides the experimental results of tube vibration response, damping ratio, hydrodynamic mass, fluid-elastic instability, and flow pattern in tube bundle. The damping ratio was very dependent on void fraction, as were in previous works. The tube vibration motion of the rotated square array was quite different from that of the rotated triangular array. Compared to the case of the rotated triangular array, tube-to-tube hydrodynamic coupling of the rotated square array is very weak, which might result in very high fluid-elastic instability constant. An ultrasonic through-transmission technique was successfully applied to identify the flow regimes in a tube bundle.