Nonlinear dynamics of a cantilevered tube with clearance constraint subject to two-phase cross-flow

• Published in: Journal of sound and vibration Vol. 459; p. 114857
• Main Authors: Jiang, Tianze, Li, Pengzhou, Ma, Jianzhong, Tan, Tiancai
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 27.10.2019; Elsevier Science Ltd
• Subjects: Algorithms; Asymmetry; Bifurcations; Boilers; Clearance constraint; Cross flow; Dynamic characteristics; Equations of motion; Flow stability; Flow velocity; Galerkin method; Motion stability; Nonlinear dynamics; Nonlinear systems; Numerical analysis; Runge-Kutta method; Steam generator tubes; Stiffness; Two phase flow; Vibration; Void fraction; Nonlinear dynamics; Clearance constraint; Steam generator tubes; Two-phase flow
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2019.114857

The main objective of this study is to determine the effects of two-phase cross-flow and nonlinear clearance constraint on the dynamic characteristics of steam generator tube bundles. The equation of motion of a cantilevered tube with nonlinear clearance constraint is established utilizing quasi-static fluid force of two-phase flow. The analytical model, after Galerkin discretization and Runge-Kutta algorithm numerical solution, exhibits several interesting behaviors of bifurcations and chaotic motions with increasing two-phase flow velocities after fluidelastic instability occurs. Numerical solutions show that, the bifurcation velocities of Hopf, pitchfork, period-doubling are delayed and the amplitudes of tube vibration at the corresponding bifurcation points become larger with increasing void fraction of two-phase. Moreover, the clearance size, constraint stiffness and asymmetry of clearance support have remarkable effects on nonlinear dynamic behavior. Larger clearance size, constraint stiffness and asymmetry lead to more complex nonlinear behavior, including distorted break along bifurcation track, inverse bifurcation and wider range of chaotic motions, so that some typical bifurcation points become indiscernible.