A fourteen-tubes based semi-analytical model for fluidelastic instability threshold prediction of tube bundles in two-phase cross flow

Abstract The semi-analytical model (a.k.a. the tube-in-channel model) needs less empirical inputs and considers interactions between tube movements and cross-flow variables, and is well used in fluidelastic instability (FEI) threshold prediction of tube bundles. However, despite numerous flexible tubes in engineering practice, tube-in-channel models with more than 7 tubes are not yet studied. In this paper, a new tube-in-channel model with a layout of 14 flexible tubes, rather than the reported 1, 5, or 7 tube(s), is established and used for FEI threshold prediction of rotated triangular tube bundles in two-phase cross-flow. Five sets of experimental data are used for verifying this model, of which the accuracy and efficiency are compared with those of tube-in-channel models with 1 and 7 tube(s). Influences of the attachment angle, the separation angle, and the time-delay parameter on performances of these three models are also investigated. Since its numerical predictions agree well with the experiments, the present 14-tubes model shows potential applications in steam generator design.