Читать книгу Flow-Induced Vibration Handbook for Nuclear and Process Equipment - Группа авторов - Страница 37

Fluidelastic instability for tube bundles subjected to single‐phase cross flow was reviewed by Pettigrew and Taylor (1991). Fluidelastic instability is formulated in terms of a dimensionless flow velocity, U_p/fD and a dimensionless mass‐damping parameter, 2πζm/ρD², such that:

(2‐25)

where f is the tube natural frequency, ρ is the fluid density, m is the tube mass per unit length and U_pc is the threshold, or critical, flow velocity for fluidelastic instability. A fluidelastic instability constant K = 3.0 is recommended for all tube bundle configurations, as shown in Fig. 2-11 (Pettigrew and Taylor, 1991). The damping ratio, ζ, is the total damping ratio as outlined in Section 2.3.2. The above formulation applies to all cross‐flow regions such as steam generator preheater regions, heat‐exchanger tube bundles between baffle plates, and outlet and inlet regions.