Xvib

Analyze vibration potential of individual tubes

Xvib® performs flow-induced vibration analysis of a single tube in a heat exchanger bundle. The program uses a rigorous structural analysis approach to calculate the tube’s natural frequencies for fundamental and higher modes and can properly handle any tube support arrangement.

Use Xvib in standalone mode or generate cases automatically from Xist® for shell-and-tube heat exchangers.

Features

  • Calculates fundamental and higher mode frequencies for straight tubes and U-tubes.
  • Calculates tube deflections using finite element structural analysis methods.
  • Analyzes fluidelastic instability and vortex shedding vibration mechanisms.
  • Analyzes both straight and curved beam elements.
  • Calculates static deflections for up to 15 modes of vibration.
  • Program uses the Xchanger Suite® interface, which allows the creation of cases directly from Xist runs.
  • Both input and output can be displayed in multiple unit sets, including user-defined sets. Dynamic display of values in all unit sets.
Xvib Geometry
Drawing displaying location of tube being modeled.

Geometry Specifications

  • Plain or low-finned tubes
  • Supports at any location on the tube or in the U-bend
  • Tubesheet, baffle, U-bend, DTSTM, and STSTM support types
  • Up to 99 spans per tube
  • Built-in databank for standard low-fin geometries

Calculation Features

  • Rigorous calculation of tube natural frequency, up to first 15 modes
  • Fluidelastic instability and vortex shedding vibration mechanisms
  • Each span divided into multiple elements (i.e., multiples of five elements)
  • Placement of multiple spans between supports increases detail in analysis
  • Optional specification of fluid velocity and density at each span element
  • Consideration of in-plane and out-of-plane velocity profiles
  • Multiple options for specifying damping characteristics in addition to HTRI default method

Outputs

  • Summary report indicates both the mode and span with vibration trouble spots in the tube
  • Vortex shedding amplitude monitor reports static deflection at every node of tube
  • Critical velocity ratio monitor reports local velocity divided by critical velocity at every node of tube
  • Extensive set of spreadsheet-style output reports can be printed or exported to Microsoft® Excel®
  • Span profile drawing with location of all supports
  • Tube layout drawing indicates which tube in bundle is being modeled
  • Tube displacement graph identifies relative deflections for all calculated modes of vibration
  • Velocity profile graph lets you visualize input data
  • User-defined graphs for easy accessibility