An experimental study into the phenomenon of aerodynamic noise generation in control valves has been performed. Several model representations of control valves have been studied, in addition to making measurements on several full size control valves. A high speed computer based data acquisition system, coupled with miniature high frequency surface mounted pressure transducers, has been used to obtain measurements of both the mean and fluctuating wall static pressures at several locations throughout the length of the flow apparatus. For known flow conditions, it has been possible to determine the relative performance of each particular model or commercial valve design by examining the various recorded levels of the wall static pressure fluctuations. A series of flow visualisation experiments, in which both wall static pressures and photographs of the flow through a rectangular duct have been obtained simultaneously, has provided a valuable insight into the mechanisms that determine the performance of multi-plate models. These findings have led to the design and commissioning of a new working section constructed from lengths of circular pipe. This apparatus has been used to investigate the performance of models constructed from two circular multi-holed test plates placed normal to the flow, with the downstream test plate being significantly more porous. Relationships between parameters such as test plate hole diameter, test plate separation, hole pitch to diameter ratio and pressure ratio have been examined extensively for many combinations of model configuration. Subsequently, the vast amounts of experimental data produced by this systematic testing have been reduced to identify the clear links between the various parameters. This, in turn, has enabled the author to determine optimum values for the non-dimensional parameters which govern the design of such multi-plate systems. As a consequence of this study, the author has proposed an alternative approach to the design of 'Low Noise' control valves which offers the prospect of improved overall performance. Thus, it is envisaged that the findings from this investigation will have implications for the future design of 'Low Noise' control valves.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:517180 |
| Date | January 1992 |
| Creators | Kirkwood, A. D. |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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