Steam generators and heat exchangers are omnipresent in industrial heating, chemical industry and power plants. These devices often consist of a cylindrical barrel filled with a bundle of long and slender cylindrical tubes. The barrel of a steam generator contains a mixture of water and steam and consequently the tubes in the barrel are surrounded by a so-called two-phase flow. Similar two-phase flows are present inside or outside the tubes in many heat exchangers.
Despite decades of experience with building these devices, still yearly thousands of steam generator tubes have to be taken out of service by plugging them and ten thousands of tubes have to be repaired. Flow-induced vibration (FIV) causes a part of this damage but this phenomenon is not really understood for two-phase flow. Therefore, the aim of this fellowship is to reduce FIV of tubes due to two-phase flow inside or outside these tubes, with focus on flow aligned with the tubes. This will be achieved by performing and analyzing numerical simulations which take the coupling between the flow and the structural deformation into account.
First, the forces due to two-phase flow around a single rigid tube and a rigid tube bundle will be calculated. Second, the effect of the structural motion will be included in the simulations. Finally, FIV due to two-phase flow inside a tube will be investigated. The results of all simulations will thoroughly be investigated to determine and understand the occurring phenomena.