• The KSFM Journal of Fluid Machinery
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• v.12 no.2
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• pp.31-38
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• 2009

The valve performance has been evaluated from the theoretical equation based on design information such as packing thrust, spring preload and friction coefficient(${\mu}$). The accuracy of those data can be lower than that of vendor's initial design data. Especially, the friction coefficient can be degraded with time than the original condition and the valve performance calculated using the previous friction coefficient can not be available. Accordingly, this paper is describing a new performance evaluation method of valve based on diagnostic test data which are acquired from a site valve tested in static and dynamic conditions. Especially, this paper provides a new method using friction coefficient(${\mu}$) which is derived from the diagnostic test data acquired in the valve's design basis condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.10
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• pp.884-888
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• 2007

It is necessary to evaluate periodically the performance of the AOV(air-operated valve) which is used for controlling flow and pressure in nuclear power plant. The required thrust for actuating valve and available thrust of actuator are calculated with conditions of flow through a valve in this study and operating performance is analyzed through comparing two thrusts. In general, differential pressure is increased according to increase the flow rate and differential pressure affects the required thrust of valve. We found the fact that it is possible not to close the valve perfectly because required thrust becomes bigger than available thrust of actuator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.686-686
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• 2013

Automotive turbochargers have become common in gasoline engines as well as diesel engines. They are excellent devices to effectively increase fuel efficiency and power of the engines, but they unfortunately cause several noise problems. The noises are classified into mechanical noises induced from movement of a rotating shaft and aerodynamic noises by air flow in turbochargers. In addition to, there is a mechanical noise caused from movement of an actuator, electronically controlling a wastegate valve. It is called as valve rattle noise. The actuator is connected to a valve through a linkage. The noise occurs only if the valve is open, where the linkage is freely contact to neighbor structures without being constrained by any external forces. This condition allows impacts by the pulsation of exhaust gas, and the vibration from the impacts spreads out through turbine housing, causing the rattle noise. The noise is not in mechanical operating wastegate turbochargers because the linkage of an actuator is strongly connected by actuating force. For the electronic wastegate turbocharger, this paper proposed a test device to show the noise generating mechanism with a small vibration motor having an unbalanced shaft. It also shows how to reduce the noise - reduction of linkage clearances, inserting wave washers into a connection, and applying loose fitting in bushing embracing a valve lever to turbine housing.