Improving Flow and Spillage Characteristics of Range Hoods by Using an Inclined Air-Curtain Technique

Abstract

The current study developed a new type of range hood, which was termed an 'inclined air-curtain range hood', in order to improve the flow and performance of the conventionally used wall-mounted range hood. The flow characteristics and oil mist spillages of air-curtain and conventional range hoods under the influences of both a mannequin presence and a simulated walk-by motion were experimentally examined. The study examined flow patterns by using a laser-light-sheet-assisted smoke-flow visualization technique and diagnosed spillages by using the tracer gas concentration test method. A mannequin presented in front of the conventional hood induced turbulent dispersion of oil mists toward the chest and nose of the mannequin owing to the complex interaction among the suction, wake, and wall effect, while the inclined air-curtain hood presented excellent hood performance by isolating the oil mists from the mannequin with an air curtain and therefore could reduce spillages out into the atmosphere and the mannequin's breathing zone. Both flow visualization and the tracer gas test indicated that the air-curtain hood had excellent 'robustness' over the conventional hood in resisting the influence of walk-by motion. The air-curtain technique could drastically improve the flow characteristics and performance of the range hood by consuming less energy.

Flow characteristics of an inclined air-curtain range hood in a draft

“…The draft effect was a kind of continuous disturbance of airflow in kitchens. It was different from the effect of walk-by mentioned by Huang et al 18 , 21 ) . Chen et al 19 ) presented the containment of conventional range hoods operating under the effect of a cross draft.…”

“… 18 ) investigated the performance of a wall-mounted range hood with laser-assisted flow visualization in static conditions (the draft of the environment was controlled) and dynamic conditions (humans walking by). A novel design of a range hood was reported by Huang et al 20 , 21 ) . A range hood with the installed inclined air-curtain was called the inclined air-curtain range hood.…”

“…No significant spillages of oil fumes or tracer-gas concentration was observed or detected around the front and lateral planes of the air-curtain range hood. The inclined air-curtain range hood presented excellent hood performance by isolating the oil mists from the mannequin with an air curtain and therefore could reduce spillages out into the atmosphere and the mannequin’s breathing zone 21 ) .…”

Flow Characteristics and Robustness of an Inclined Quad-vortex Range Hood

“…2 ). For comparison, the data for the IAC and conventional range hoods were quoted from Huang et al 20 , 21 ) . The conventional range hood has a very low robustness.…”

“…Huang et al . 20 , 21 ) represented an inclined air-curtain (IAC) range hood which was designed by combining a suction slot installed at the hood and a plane jet arranged at the front part of the countertop to form a backward-inclined push-pull air curtain. They showed that the IAC range hood has higher performance than the conventional range hoods under both the static and dynamic tests.…”