Condensate downcomer vibration is a common phenomenon in the direct air cooling system

which endangers the safe operation of the air cooling system when the vibration is serious. The pipe vibration model is established based on the fluid solid coupling method. The two-phase flow characteristics of the condensate pipe are analyzed using the theory of flow induced vibration and fluid cavitation. The model analytical calculation and numerical simulation are carried out for the condensate pipe of a 660 MW ultra supercritical unit. The results show that saturated or nearly saturated condensate flows from the air cooling platform along the condensate downcomer to the hot well of the steam exhaust device by gravity flow. When the potential energy of water is released

twophase flow excitation and cavitation phenomena occur. Based on this analysis

the causes of condensate vibration and cavitation noise are found

By using multi-stage Venturi tubes and porous orifice plates in the condensation water pipeline of the power plant to eliminate the condensate potential energy

avoid excessive pipeline vibration and noise

and eliminate the hidden danger of pipeline vibration.