Sensitivity Measurement of a Horizontal Hydrostatic Bearing System for a Bulb-type Model Turbine Test |
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학술지명 ASME (미국기계학회)
저자 이교현,권성일,김영준,조용
발표일 2016-07-12
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The reduced scale homologous model testing is one of the important process in development of a large hydraulic turbine system. During the model test, various measuring instruments such as flow meters, differential pressure gauges, load cells, and RTD sensors are used to acquire the precise measurement data after the calibration test for each instrument. For an efficiency test, hydraulic power can be measured by acquiring discharge flow rate and total pressure between inlet and draft tube, and the power output of the turbine can be measured by acquiring the rotating speed and the torque of the turbine. In general, torque of a hydraulic turbine is transmitted to a dynamo-system, in which torque can be measured, via mechanical systems such as bearings, seals, and gears. In order to acquire accurate torque value, the main torque measured at a dynamo-system should be compensated for mechanical loss generated from the intermediate mechanical system between a turbine and a dynamo-system. In case of a bulb-type model turbine, accurate turbine torque including the relevant total friction can be measured if a horizontal hydrostatic bearing is installed in a bulb of a model turbine. To prevent incorrect functioning of a hydrostatic bearing, its sensitivity should be checked to be in a range referred in a model test standard of IEC 60193. A sensitivity measuring device is designed to indicate very small torque in various thrust load conditions. In the device, an additional hydrostatic bearing is applied to produce the thrust force under the frictionless condition. In horizontal thrust load conditions, the sensitivity measuring test are carried out with various test conditions for the developed hydrostatic bearing system. |