In 2003, Elliott-Ebara Company and the MSU Turbomachinery laboratory carried out a series of experimental and numerical studies on a venturi valve application for stream turbines. It was proved by the studies that a non-axisymmetric flow pattern caused non-axisymmetric pressure distribution along the plug and generated an unbalanced force and moment at the valve. This excited the plug, and the plug could be broken in a very short time if the amplitudes of these excitations were to become large over the short time. A new governor valve was designed to reduce flow non-axisymmetry and instability. To investigate the relationship between plug and seat, the newly designed governor valve was tested under the same conditions as the previous valve test. In the new experiment, four microphones and five accelerometers were set up to study the new valve's interaction with fluid in addition to the static pressure taps from the previous experiments. The results of model experiments on a newly designed governor valve are reported here. Mass flow rates for new LRCO valves are measured at different valve openings and pressure ratios. To clarify the interaction of the new LRCO valves with the working fluid, flow axisymmetry and instability are discussed.
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