Experimental device for the study of Liquid–Solid coupled flutter instability of salt cavern leaching tubing

Abstract A salt cavern underground gas storage is typically constructed by water solution mining, in which slender leaching tubings are used as the channel for water injection and brine production. Cavern leaching and well workover operations are accident prone owing to leaching tubings being bended excessively and even ruptured. These accidents are caused primarily by flow-induced vibration of leaching tubings. To investigate these flow-induced vibration phenomena, an in-house laboratory device for liquid–solid coupled flutter instability of salt cavern leaching tubing was developed. This experimental device consists primarily of a recirculating flow system, vertical cantilevered pipe test section, and instruments for parameter measurement. The experimental device can be utilized to investigate multiple factors involved in the flow-induced vibration of the leaching tubing, including flexural rigidity, overhang length, and support conditions of tubing string. To verify the adequacy of this device, two sets of experiments have been performed in the air without external space constraints by using a cantilevered silicon rubber and polycarbonate pipes, respectively. Flutter instability phenomena were observed in these experiments. Furthermore, through the study on the length effect, an asymptotic behavior with the critical flow velocity reaching limiting values as the lengths of the pipes increase, is discovered. The present study is conducive to the subsequent experimental step that considers additional factors. Consequently, the device provides adequate in-house experimental conditions for researching the instability mechanism and safety control measures of the leaching tubing.