A Comparison of Three-Dimensional Velocity Models for Flanged Rectangular Hoods

Abstract

Air velocity measurements are used to evaluate the accuracy of three models presently available to predict the three-dimensional velocity field into flanged rectangular exhaust hoods. Measured velocity vectors into flanged rectangular hoods are in closest agreement with a potential flow solution developed by Tyaglo and Shepelev. Three flanged rectangular hoods with aspect ratios of 1, 2, and 5 were operated at flows of 112, 131, and 143 cfm. Measurements of the air velocity magnitude and direction were made with a thermoanemometer and smoke tubes in both planes of symmetry that contain the hood centerüne. The velocities ranged from 80 percent to 5 percent of the face velocity.