Abstract
The prediction of noise in industrial control valve applications is required to select the correct control valve design for the end user to keep their employees and equipment safe as well as meet any local noise ordinances. In a piping system any noise generated by a valve or other component will propagate within the downstream pipe. This internal acoustic field will couple to the pipe wall and cause it to vibrate, which in turn causes external radiation. The difference between the internal and external sound fields is called transmission loss. The estimation of the transmission loss can be a major contributor to the accuracy of noise prediction methods.
The theory that is the basis of the pipe wall transmission loss calculation in the international standard IEC 60534-8-3 Control Valve Aerodynamic Noise Prediction Method is reviewed and reanalyzed to correct an error. Then critical variables such as uniform mean flow, internal acoustic modal density, and structural modal density are reevaluated.
Based on the complete reanalysis, suggestions for improvements to the calculation methodology used in noise predictions are provided and the estimated change is quantified. Experimental data taken in a flow system designed to measure control valve noise was used to inspect a few variables and the overall prediction methodology. Future research areas are also suggested.
