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Mitigation of Self-Excited Vibrations in Spring-Loaded Valves
Salim El Bouzidi, Marwan Hassan, Samir Ziada

Last modified: 2018-07-15

Abstract


Spring-loaded valves are widely used in industrial applications. Their self-acting ability, which allows them to open or close based on pressure conditions, makes them particularly instrumental for safety-relief applications in power and chemical plants. In these cases, valves open systematically as an emergency measure if the pressure in the pipeline exceeds operational specifications. They are also often used as directional valves in reciprocating compressors. In gas compression and safety relief applications alike, traditional valve design has mainly relied on steady, time-independent characteristics of the system. However, dynamic fluid loading can result in vibrations that severely hinder the operation of the valve either by reducing its performance or through premature wear.

Spring-loaded valves have been reported to experience self-excited vibration in reciprocating compressor installations as well as in safety relief devices of pressurized systems. Prior work by the authors has provided an experimental characterization and a theoretical model of the flow-sound-interaction mechanism which causes the self-excited vibration. It was found that the vibration occurred only when the fluid-structure interaction at the valve is coupled with acoustic reflections in the associated piping system. In other words, coupling with the pipe acoustics was essential for the initiation of the self-excited valve vibration.

The current investigation evaluates the effectiveness of three acoustic devices on the self-excited vibration. The objective is to dampen the sound waves in the piping system to weaken its coupling with the valve oscillations. A concentric cavity resembling Helmholtz resonator, an orifice plate, and an anechoic termination are placed at the downstream side of a model valve which exhibited strong self-excited vibration in previous investigations. The effectiveness of each countermeasure for various values of pipe length and spring stiffness will be discussed in detail in the paper.


Keywords


valve vibrations; flow-sound-structure coupling; self-excited oscillations;

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