A study of 3-dimensional flow through orifice meters /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | Uncertainty in orifice metering accuracy is estimated to account for mischarges on the order of 250 million dollars annually in the natural gas industry. Consequently, attempts are now being made to improve the accuracy of existing orifice metering facilities. Most prior efforts toward this end have concentrated on determination of the discharge coefficients. The objective of this study was to increase the knowledge of the flow field present in a typical orifice meter. This was accomplished by using a 3-D LDV (Laser Doppler Velocimeter) to collect detailed 3-D velocity measurements within an orifice meter (β=0.50 and 0.75). The working fluid was air at pipe Reynolds numbers of 18,400, 54,700 and 91,100. Reduction of the correlated, instantaneous velocities in three dimensions enabled calculation of the component mean velocities and previously unavailable complete Reynolds stress tensor. This information was then used to compute a number of other quantities including vorticity, turbulence kinetic energy, turbulence kinetic energy production rate and correlation coefficients. The FLUENT code of Creare, Inc. was used to simulate the orifice meter with the same conditions as those at which the 3-D LDV measurements were taken. Vena contracta location, minimum wall pressure as well as reattachment length were determined for both the experimental and computational results. Analyses and comparisons were done on and with the LDV and FLUENT results. The existence of a secondary recirculation zone was established and the consequences discussed. An analogy between the jet issuing from the orifice plate and that of the sudden pipe expansion is suggested. The Reynolds stress information enabled evaluation of theoretical conjecture concerning shear flows as well as established the existence of organized turbulence structures in that region. Comparisons between FLUENT and LDV revealed generally good agreement but an overprediction of the rate of spread of the jet was documented. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Mechanical Engineering." |
| Physical Description: | xv, 178 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |