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ISSN Druckformat: 1065-3090
ISSN Online: 1940-4336
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EXPERIMENTAL INVESTIGATION OF SPOILAGE EFFECTS ON THE ULTRASONIC DOPPLER VELOCIMETER PROFILES USED FOR VOLUMETRIC FLOW RATE CALCULATIONS OF A PIPE FLOW
ABSTRAKT
The performance of an ultrasonic Doppler velocimeter (UDV) in on-line determination of the volumetric flow rate by velocity profile measurements in pipe flow was investigated. Recycling and nonrecycling water flow systems were built and used for this purpose. Two volumetric flow rate calculations were performed for each flow rate by using two halves of the velocity profile measured. One half is near to and the other half is far from the UDV probe. The results revealed that the volumetric flow rates determined by the UDV velocity profiles are deviating from actual values by a noticeable amount above a specific flow rate for a recycling setup. This value is around 0.48 L/s for the investigated pipe of inside diameter of 0.046 m. In the case of the nonrecycling flow system, such severe deteriorations of velocity profiles were not observed and correct volumetric flow rates could be computed from these profiles. Additionally using far half velocity profiles gave more accurate results compared to the near half velocity profiles in both flow systems. The results have indicated some possible concerns that must be considered as well as the artifacts on the velocity measurements of near wall region because of strong ultrasound and pipe wall interactions. These artifacts disappeared with increasing flow rate as a result of increasing signal/noise ratio. Therefore a UDV operator should be aware of the issues emphasized within this text, in order to be able to get more accurate velocity profiles in a pipe flow.