The problem relates mainly to the unsteady pressure measuring systems when they contain any type of pneumatic transmission line. Such a line usually has the form of a tube or bore of small diameter. A variation of the time-averaged pressure along the tube appears when the relative pressure amplitude at the tube inlet is significant. This is caused by summation of nonlinear effects of the gas motion inside the tube. The viscous and heat conducting gas is considered. The aim of the present work is to determine the relation between time-averaged pressure at the inlet and at the end of the tubes. The unsteady, compressible boundary-layer equations for axisymmetrical gas flow in the tube were adopted as the basic equations of the problem. The perturbation method has been used for solution of the equations. A first-order linear solution is presented in literature. A new second-order solution has been derived herein. The results of calculations for single tubes and for systems of two consecutive tubes of different diameters are presented in a form convenient for practical use. The qualitative and quantitative agreement of the theoretical results with available experimental data has been found.
Time-averaged pressure of fluctuating gas motion in small-diameter tubes
Zeitlich gemittelter Druck einer flukturierenden Gasbewegung in Roehren mit kleinem Durchmesser
AIAA Journal ; 25 , 4 ; 567-572
1987
6 Seiten, 6 Bilder, 10 Quellen
Aufsatz (Zeitschrift)
Englisch
DRUCKMESSUNG , DURCHMESSER , ROHR , VISKOSITAET , WAERMELEITUNG , GAS , GASSTROEMUNG