Effects of Mannequin and Walk-by Motion on Flow and Spillage Characteristics of Wall-Mounted and

Laser-assisted flow-visualization experiments and tracer gas concentration tests were con-ducted for the wall-mounted and jet-isolated range hoods to examine the physical mechanisms and relative magnitudes of hood spillages. The effects of a mannequin standing in front of the test rig and walk-by motions (which are situations always encountered in kitchens) were em-phasized. The results showed that a mannequin (or a cook) standing in front of the counter would attract oil fumes toward the mannequin’s body, induce large turbulent flows, and cause a significant dispersion of oil fumes into the environment through the front edge of the hood. Very high tracer gas concentrations were detected around the breathing zone of the manne-quin. Increasing the suction flow rate did not reduce the spillage levels of the wall-mounted range hood but could moderately lower those of the jet-isolated hood. Serious spillages from both the wall-mounted and jet-isolated range hoods were detected as the simulated walk-by motion was performed. The jet-isolated range hood presented a much lower robustness in re-sisting the influence of people’s walk-bys than did the wall-mounted range hood. In summary, both the wall-mounted and jet-isolated range hoods were vulnerable to the influences of a cook’s presence and a cook’s walk-by motions. Increasing the suction flow rate might not obtain satisfactorily low spillages of pollutants but might increase noise level and energy consumption