1993 Volume 36 Issue 2 Pages 230-237
A new technique of an active attenuator for pressure pulsation in liquid piping systems, which detects the progressive wave component of fluid-borne vibration and then controls the second source feedforwardly by this detected signal so as to completely eliminate the progressive wave in its downstream pipe by producing the canceling fluid vibration, has been presented, together with experimental results. As a preliminary investigation in this study, an experiment on the attenuation characteristics has been carried out for only the simple harmonic fluid vibration, though the present active attenuator using the transfer-function-based control method is also applicable to the wide-band random fluid vibration. A general-purpose digital signal processor has been used for the high-speed operation of converting the pressure difference signal produced by two pressure transducers into the progressive wave signal of fluid vibration and for the successive operation of producing the control signal to the second source (electrohydraulic servo cylinder). It was confirmed by the test in a model experimental pipeline that, when the present control system was operated, the pressure pulsation in a downstream pipe of the second source was reduced, as expected, to about 1/10 to 1/15 (that is, a transmission loss of about 20 to 25 decibels) of that in the case where the control system was not used over the frequency range of 20 to 250Hz.