| This dissertation reviews the literature on noise generation in control valves, concentrates on a problem called "screech" that occurs in control valves which has not been thoroughly studied before. Screech describes a condition where pipe resonances are excited by flow instabilities in a control valve and result in higher-than-normal noise and frequency levels.; A large amount of test data documenting screech is compared with the characteristics of a variety of valve trim (valve internals) types, models for screech production are proposed and validated, a design procedure is proposed that eliminates screech problems and standard test parameters are identified and procedures recommended that evaluate a valve trim design's susceptibility to screech. |
