Experimental Studies of Tube Frettings in Steam Generators and Heat Exchangers

High flow rates in steam generators and heat exchangers may create flow-induced tube vibrations which cause local wear through impacting and rubbing on tube supports and/or with adjacent tubes. The steam generators in CANDU power plants have a design life of 30 yr; it is, therefore, essential that design criteria be developed to minimize tube fretting and to establish acceptable limits of vibration. Standard equipment has been developed to study the effect on tube fretting due to various parameters, such as tube/tube-support interaction, materials combinations, and support geometry. Tests have been conducted in water and steam at boiler operating temperature (265°C) and at room temperature.