SwRI Machinery Vibration Services: Flow-Induced Vibration and Noise. SwRI has establish reducing the risk of crankshaft failure in Large integral reciprocating compressors

  image of design modifications of HRSG tubing baffles
 

Design modifications of HRSG tubing baffles resolve unexpected flow-induced vibration problems of newly installed turbine.

With certain flow conditions, piping systems will develop high levels of noise and vibration that can damage the pipes and related systems such as tube bundles, side cavities, and bluff or tapered bodies in flow streams. Pipe damage compromises plant safety, forces shutdowns, increases maintenance, and reduces efficiency and capacity.

 

SwRI identifies the cause of flow-excited acoustic resonance in piping systems and components and develops engineered solutions with vibration testing and design analysis.

 

Safety Relief Valves

Flow past a valve entrance cavity excites a standing wave, resulting in noise and vibration. A similar tone is produced when air is blown across the mouth of a pop bottle.

 

Symptoms of Flow-Induced Acoustic Resonance

Noise is often present with high vibrations. In milder cases, the problem may be annoying vibration and noise. Maintenance and replacement of valve parts may be an issue. In severe cases, pulsations can

 be amplified to more than 200 psi by acoustic resonance. Fatigue damage to tube bundles and small piping can result.

 

Cause of Flow-Induced Acoustic Resonance

  graphic of flow-induced acoustic resonance
 

Entrance edge treatment and detuning control pulsation

Vortices develop as flow passes over obstructions of side cavities. These vortices can excite pulsation or vibration, which can be greatly amplified if acoustic or structure resonance occurs. Solutions require minimizing vortice generation or detuning acoustic or structural resonance.

 

Results of Flow-Induced Acoustic Resonance

Acoustic resonance may cause:

  • Mechanical vibrations

  • Valve chatter

  • Fatigue failure

  • Fretting

  • Wear

  • Excessive noise

      graphic of compressor inlet section
     

    Acoustic standing waves related to flow splitter length amplified pulsation in a pipeline compressor, resulting in fatigue damage. Engineered splitter edge treatment reduced vortice generation and reduced pulsation.

Solutions

Measurement techniques identify flow-induced responses across tube bundles, side cavities, and bluff or tapered bodies in flow streams. Experienced in on-site and remote monitoring, SwRI engineers can rapidly identify flow-induced acoustic resonance and its characteristics and solve flow-induced vibration and noise problems with safety relief valves, heat exchangers, heat recovery steam generators (HRSGs), condensers, and flow splitters.

 

Institute engineers can modify existing piping configurations or design new ones, based on the results of field testing and acoustic simulation. We can provide solutions for a number of power and petrochemical plant piping systems.

 

For more information about machinery vibration services or fan and duct dynamics capabilities at SwRI, or how you can contract with SwRI, please contact  Harold Simmons, P.E., at hsimmons@swri.org or (210) 522-2557.

©1998-2009 Copyright Southwest Research Institute
Printed from:
http://www.swri.org/4org/d18/mechflu/planteng/machvib/dt5.htm?
Southwest Research Institute® (SwRI®) is an independent, nonprofit, applied engineering and physical sciences research and development organization with 12 technical divisions using multidisciplinary approaches to problem solving. The Institute occupies more than 1,200 acres and provides nearly two million square feet of laboratories, test facilities, workshops, and offices for more than 3,300 employees who perform contract work for industry and government clients.