Acoustic-induced vibration (AIV) and flow-induced vibration (FIV) are two common phenomena that can lead to vibration-induced fatigue failures in piping systems. Pipeline facility managers, operators, designers, and engineers are faced with identifying and mitigating the risks of AIV and FIV to avoid catastrophic instances of vibration-induced fatigue failures in their facilities. This paper identifies common challenges to conventional AIV/FIV analyses methods, and discusses advanced techniques available to address these challenges.
Acoustic-induced vibrations are caused by the sound energy created by flow through pressure reducing devices like valves or restrictive orifice plates. This sound energy can cause the piping wall to vibrate, thus exciting, and possibly damaging, any nearby small-bore branch connections. Flow-induced vibrations are caused by pulsations induced by flow past dead legs in piping systems. These pulsations can create shaking forces that cause vibrations of piping, vessels, and equipment. The two phenomena will be compared and contrasted, while offering simple tips and best practices in identifying, evaluating, and solving these two common flow-induced issues.
A field case study utilizing pulsation and vibration measurements between a line heater and inlet separator for a gas plant will be presented and discussed. The case presents an opportunity to investigate mainline and small-bore piping AIV/FIV risks in plants, provides example data of clear AIV and FIV phenomena, and identifies complex situations that require more rigorous analysis. Advanced techniques for analyzing and solving complex issues that are commonly found in piping systems will be explored. Further, the case highlights the benefits of early screening and preventive considerations of upset conditions when dealing with flow-induced pulsation and vibration issues.
In this paper, the reader will gain an increased understanding of the importance of AIV/FIV in maintaining integrity of their facilities, and be provided with tools and knowledge to mitigate any risks that may be encountered.