Effects of Mean Flow on the Dynamic Characteristics of Fluid Transmission Lines

摘要

Theoretical predictions of the small signal frequency response of round pneumatic transmission lines with turbulent mean flow were compared with experimental results. The frequency response curves were found for lines varying in length from 24 to 36 in. with inside diameters of 0.195, 0.119, and 0.041 in. The lines were tested at Reynolds numbers of 2000, 5000, and 10000. Theoretical solutions were obtained using Nichols' equations as modified by Krishnaiyer and Lechner. Solutions were also found using several different modifications of a constant LRC model developed by Moore. The results were mixed: for the 0.195 and 0.119 in. lines the prediction of gain was good but for the 0.041 in. lines the results were poor. The accuracy and applicability of the constant LRC model was explored along with its various modifications. The constant LRC model with the AC resistance showed potential for predicting the gain in fluid transmission lines with turbulent flow. The limitations and applicability of the constant LRC models were studied. (Author)