Study on the Vibrational Characteristics of a Tube Array Caused by Two-Phase Flow. Part I: Random Vibration

Abstract There are few published papers on the subject of flow-induced vibrations caused by two-phase flow. Experimental data at the high pressure and temperature conditions which would correspond to practical operating conditions are extremely few. Furthermore, the mechanism of the two-phase flow-induced load acting on a tube in a tube array has not yet been explained. This paper presents the experimental results on turbulent buffeting forces generated both by air-water flow and by steam-water two-phase flow for the extreme pressure conditions up to 5·8 MPa and temperatures reaching 272°C, the explanation of the mechanism producing these forces, and a method for evaluating the tube response caused by two-phase flow. Here, the main source of the buffeting forces in slug or both two-phase flow is recognized to be the impact forces caused by the intermittently rising water slugs. The slug speed and the fluid forces acting on a tube are estimated, together with an estimation of the period of the occurrence of the rising water slug. The accuracy of this estimation method is proved by comparing the theoretical response with the measured one.