Experimental Investigation of Fluidelastic Instability in In-Line Tube Arrays

Abstract The Helical Tube intermediate heat exchanger (Helical Tube IHX) is a crucial component for process heat applications and hydrogen production in Very High-Temperature Gas-Cooled Reactors (VHTRs). Due to the coil design with a large spiral diameter in the Helical Tube IHX, the fluidelastic instability needs to be given special attention. The simplified straight tube bundle model and inclined tube bundle model were designed and constructed to inclined study the fluidelastic instability of single flexible tube in the center of the bundle. A variable magnetic eddy current damping system has been constructed and utilized to change the tube’s damping ratio. The critical flow velocities for fluidelastic instability in tube bundle model were obtained under different mass damping parameters. By comparing the instability maps of the straight tube bundle and the inclined tube bundle, the results indicate that the inclined tube bundle is more prone to instability compared to the straight tube bundle.