Development of an active Attenuator for pressure pulsation in liquid piping systems. 1st report. A real time measuring method of progressive wave in a pipe.

Abstract

This paper deals with a real-time measuring method of the progressive wave of fluid velocity pulsation in a pipe, which is necessary for the development of an active attenuator of pressure pulsation in liquid piping systems. The principle of the present measurement is to obtain the fluid velocity (cross-sectional average velocity) signal by integrating the difference between signals produced by two pressure transducers spaced a suitable distance apart, on the basis of the momentum equation, and then to obtain the progressive wave component of fluid velocity pulsation from the pressure and velocity signals by a simple algebraic operation according to the plane wave theory. A general purpose digital signal processor (DSP) has been used for the high-speed calculation necessary for the real-time measurement. The measured values agree with the theoretical results within the experimental errors mainly due to the detection accuracy of the pressure transducer and the resolving power of the A/D converter of DSP, except for the frequency ranges of nearby resonant frequencies. The applicable limit of this measurement is the frequency range above about 15Hz mainly because of the detection accuracy of the pressure transducer.