Session: FSI-02-02: Flow-Induced Vibration

Paper Number: 84921

84921 - Combining Acoustic Induced Vibration and Flow Induced Vibration Acoustic Induced Vibration and Flow Induced Vibration Assessments 

During testing to support a program to improve acoustic induced vibration (AIV) assessments, it became clear that flow induced vibration (FIV) is excited at the same time; both mechanisms excite the shell flexural modes of the piping system, although their frequency characteristics are different but overlap.  Typically, AIV and FIV are evaluated separately, however review of some of the AIV assessment methods suggests that they effectively include an FIV assessment.  In the case of a PSV tailpipe joining a sub-header at a tee, the FIV is primarily present near the tee while AIV also present away from the tee.  Therefore, combining the AIV and FIV assessments unwittingly into one assessment, misses this important point and can for example results in significant conservatism away from the tee.   Formulations for the FIV prediction and combining AIV and FIV into a pipe fatigue life assessment are presented.  The primary difference in the formulations is the assumptions on frequency dependence for the fatigue assessment.  Data from a flare header test system is used to demonstrate the formulations and justify simplifications.  The flare header test system consists of an NPS6x8 pressure relief valve, an NPS12 tailpipe with a tee connection to an NPS20 header.  There are small bore connections in the tailpipe and header, but the work will focuse on the header and tailpipe.

Presenting Author: Adin Mann Middough Inc.

Presenting Author Biography: N/A

Authors:

Hisao Izuchi Chiyoda Corporation
Rob Swindell Wood
Adin Mann Middough Inc.