Effect of Pipe Roughness on Orifice Flow Measurement

摘要

Flow measurement with orifice flowmeters is simple in concept and can be accurate, but, as demonstrated in flow measurement test facilities, can also result in large errors if any of the significant parameters are not controlled. Many of these parameters are well known and particular care is taken to ensure that they do not cause measurement errors. Others are more subtle and not so easily detected or controlled. One such parameter is the surface finish of the pipe immediately upstream of the orifice plate. Results of an experimental investigation into the effects of this pipe roughness on the orifice discharge coefficient are presented, along with a review of some of the pertinent literature. Measurement errors of approximately 1% can result from using meter tubes that are too rough but still within the specification of the standards.