Generation of Unsteady Pipe Flow with Arbitrary Waveform by Butterfly Valve

Abstract

Investigation on the characteristics of unsteady pipe and duct flows is increasingly important because of precise control of these flows and safety of pipelines in many industrial processes. A variety of methods have been developed for producing various types of unsteady flows. Unfortunately, those capable of producing unsteady flows of arbitrary history are very limited. In this study a butterfly valve is used and it is driven by a stepping motor following programmed rotation speed. The valve is not rotated but swung around its supporting rod. Constant-acceleration flows, constant-deceleration flows, and pulsating flows with sinusoidal and triangular waveforms can be generated with sufficient accuracy.