Subsea vehicle pump pulsation measurements.

Abstract

The use of seawater ballast pumps for small undersea vehicles has increased demands for noise reduction in such subsystems. With severe constraints on volume, weight, and efficiency and the need to operate at high head pressure, the usual noise reduction techniques used on large submarines are not feasible. There are stringent requirements on a measuring system to evaluate such subsystems. To prevent biased results due to the differing spectral content of various subsystems, nonreactive acoustic termination is required. Also, care must be taken to ensure that the hydraulic load providing the required back pressure does not contaminate the results with its own noise. This paper describes an easily assembled system meeting the requirements for testing in a laboratory environment. Data were taken on two styles of water pumps to evaluate the system. Two in-line acoustic filters (mufflers) of the commercially available ‘‘three pipe’’ configuration were tested with one of the pumps and compared to analytical results using a transmission matrix model. The results indicate significant insertion loss over a broad frequency range. [Work supported by Alliant Techsystems internal IR and D funding.]