STV-10 Evaluation of Fluidelastic Instability Analysis

S. S. Chen

This report provides a review of the state-of-the-art methods for fluidelastic instability analyses in shell-and-tube heat exchangers. Topics addressed in this report include

  • prediction of tube vibrations for various tube arrays in water flow, gas flow, and two-phase flow
  • flow field, fluid forces, and tube response
  • analytic methods, experimental techniques, and mathematical models
  • design guides, design assessment, and methods of eliminating fluidelastic instability
  • research needs

Fluidelastic instability of tube arrays in crossflow in steam generators and heat exchangers is an important mechanism that can also cause damage. Motion-dependent fluid forces are the key to predicting fluidelastic instability of tube arrays in crossflow. This report describes experimental methods for measuring the motion-dependent fluid forces and computational fluid dynamic (CFD) techniques to predict fluid forces that act on tube arrays as a consequence of tube motion. Fluid-damping and fluid-stiffness coefficients based on unsteady flow theory can be obtained as a function of reduced flow velocity, excitation amplitude, and Reynolds number. A mathematical model based on unsteady flow theory is included.