• Rong Fung Huang, Gene Shin Liu, Yu-Kang Chen, Wen-Yu Yeh, Chun-Wann Chen, and Chih-Chieh Chen.
• Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan. rfhuang@mail.ntust.edu.tw
• J Occup Environ Hyg. 2004 May 1; 1 (5): 283-8.

AbstractEffects of flange size on the flow patterns of an exterior circular hood subject to the influence of various uniform cross drafts were studied in an apparatus consisting of hood-model/wind-tunnel assembly. The cross draft to suction velocity ratio covered the range from 0.056 to 0.792. The flange width to hood diameter ratio spanned from 1.2 to 3.0. The hood equipped without flange was also probed. A two-component laser Doppler anemometer was used to measure the velocity field on the symmetry plane. The streamline patterns were obtained from the measured velocity data. The cross draft caused a capture envelope. The boundary of the envelope was described by a dividing streamline. It was found that the flange width presented complex effects on the capture envelope and the dividing streamline. Corresponding to a cross draft to suction velocity ratio, a critical flange width existed. If the flange width was smaller than the critical value, the dividing streamline would terminate at the downstream tip of the flange. The behaviors of the capture envelope and the dividing streamline of the hood in cross draft under different flange widths are presented and discussed.

7 keywords...

hide…