Acoustically Induced Vibrations (AIV)
AIV refers to structural vibration excited by intense pressure fluctuations in a compressible flow stream. Process plants have a number of requirements for abrupt pressure reductions, which invariably generate some amount of acoustic vibration. This is normally accomplished through the use of the following:
- Blow down valves and restriction orifices
- Relief valves
- Pressure reducing valves
- Compressor recycle valves
The pressure reduction process induces turbulent pressure fluctuations in the flowing medium, which in turn excites the downstream pipe wall, causing stresses and potentially fatigue failure. The intensity of vibration tends to increase with mass flow rate, velocity, and pressure loss. The accompanying sound radiation is typically broadband in the range of 200 Hz to 20 kHz, with a peak somewhere above 1 kHz. AIV failures are known to occur preferentially at non-axisymmetric discontinuities in the downstream piping, such as at small-bore branches and their welded supports.
E2G|The Equity Engineering Group, Inc. uses a rigorous methodology to predict AIV failures and provide remedial actions. This methodology starts with the identification of processes requiring analysis and concludes with recommendations to reduce dynamic stress levels where the potential for fatigue failures puts your facility at risk.
E2G can mitigate the impacts of AIV and reduce costs associated with increased piping schedules.