In this paper, we formulate an experimental method to examine the pump acoustic characteristics and report the test data. First, we assess the resonance effects in the test loop by calculating the acoustic impedance and reflection coefficient at the pump ports from local pressure field measurements. Next, we decompose the measured signal into the components associated with pump action and loop acoustics with the use of a simple pump model based on linear superposition of pressure wave transmission and excitation.
We apply this technique to examine the acoustics of a single-stage, double-volute centrifugal pump. We estimate the strength of source variables at the blade-passing frequency and establish the pump characteristics as an acoustic source. The results indicate that the source variables are nearly free of acoustic resonance effects in the test loop. The pump characteristics, however, depend on the location of pump ports and loop acoustics; that is, a given pump may act either as a pressure or as a velocity source.