2970 (RP-451) -- Influence of Upstream Disturbances on Correlation Coefficient for Vane Anemometers at Coil Faces PDF

Previous work by the authors and others have shown the potential for using rotary vane type anemometers at the coil face for determining airflow rates in air-conditioning and air handling systems. However, when the anemometer is placed in direct contact with the coil, as is recommended for repeatable results, a correlation or correction coefficient is necessary to relate actual flow to the anememeter indicated value. This paper reports the results of an experimental investigation conducted to determine the effect of upstream disturbances on the velocity correlation coefficient for coils. Disturbances considered were sirroulated dirt build-up on the coil face, parallel blade dampers, and fan blasts. Depth of coil, average face velocity, and the ratio of maximum to minimum anemometer velocity reading were shown to have a significant effect on the results of using the correction factor when these disturbances are present.

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