Dynamic Behaviour of Transfer Coefficient in Pulsating Laminar Tube Flow

Abstract

The frequency response of transfer coefficient to flow-rate change in laminar tube flow is studied experimentally and analytically.In the analysis, the linearized basic equation is solved both numerically and by using a similarity variable which is used in analysis of steady-state problem. In the experiment, the variations of local value and space-averaged value with respect to time are measured under two heating conditions, i.e., constant wall heat-flux and constant wall temperature. From these results it is concluded that the similarity relation is not preserved in unsteady state and that resonance occurs in variation of transfer coefficient. This resonance point is characterized by a parameter SnPrX2/s which is derived from a similarity relation. In the last part of this paper, the effect of pulsating flow on the time-averaged transfer coefficient is discussed.

Fundamental Study on Particle Transportation by Pressure Waves in Pipes—The Characteristics of Particle Transportation— [Translated]^†

“…The unsteady flow in pipes has been researched with focus on oscillating f low 9,10) and pulsating flow [11][12][13] , where oscillating flow is superimposed on a mean f low. In pneumatic transportation, experimental research on the behavior with pulsating flow 14) was clarified, but it seems that there has been no research on pulsating f low or oscillation flow using pressure waves.…”