Effect of ninety degree elbow on the accuracy of a non-magnetic, insertion paddle wheel flowmeter
- Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering
Monitoring energy use in commercial and institutional buildings often requires measurement of chilled and hot water. For retrofit applications, insertion flowmeters are an economical alternative to fixed flow meters such as orifices or venturi meters. The insertion flow meters can be hot tapped into the piping without having to shut down operations. A major problem encountered in retrofit applications of flow meters is finding a location in a pipe where there is at least 10 to 15 diameters of straight pipe. Piping in buildings is constrained by the layout and design of the building, there may only be short runs of straight pipe where flowmeters can be installed. The purpose of this study was to quantify the measurement error caused by installation of flow meter downstream of a 90 degree elbow. The flowmeter was an insertion type, nonmagnetic, paddle wheel flow meter. Meter locations from 2.1 to 9.8 diameters downstream of a 90 degree elbow were studied in a 0.1 in diameter pipe for flow velocities ranging from 0.3 to 3 m/s. At each location downstream of the elbow, the meter was also rotated in 45 increments (from 0 to 180{degree}) around the circumference of the pipe to evaluate choice of circumferential location on flow error. Output from the flowmeter was compared to results obtained with load cells on a 38 m{sup 3} tank that collected the flow pumped through the test section. Results were presented in terms of percent error relative to the load cells as a function of downstream location, circumferential rotation angle, and velocity. The largest errors occurred at 2.1 diameters downstream of the elbow and 180 degree rotation angle. Velocity of the water appeared to have little influence on the results for velocities ranging from 0.3 to 3 m/s. Uncertainty results for all major measurement points are also presented.
- OSTI ID:
- 116220
- Report Number(s):
- CONF-950336-; ISBN 0-7918-1300-2; TRN: IM9545%%187
- Resource Relation:
- Conference: American Society of Mechanical Engineers/Japanese Society of Mechanical Engineers/Japan Solar Energy Society international solar energy conference, Lahaina, HI (United States), 19-24 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Solar engineering 1995: Proceedings. Volume 2; Stine, W.B. [ed.] [California Polytechnic Univ., Pomona, CA (United States)]; Tanaka, Tadayoshi [ed.] [Electrotechnical Lab., Ibaraki (Japan)]; Claridge, D.E. [ed.] [Texas A and M Univ., College Station, TX (United States)]; PB: 582 p.
- Country of Publication:
- United States
- Language:
- English
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