• 한국유체기계학회 논문집
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• 제7권1호
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• pp.17-23
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• 2004

Aeroacoustic characteristics of sirocco fan used in Over-The-Range (OTR) has been analyzed in this paper. A microwave hood combination over the gas range is short for the OTR. The flow phenomena of the double-sided sirocco fan was analyzed numerically and experimentally by using commercial code and three dimensional PIV for flow visualization. Also, microphone array is used in order to understand acoustic characteristics of OTR. Two dimensional unsteady flow and acoustic simulation is tried to qualitatively estimate the effects of tonal noise and broadband noise on the overall sound pressure level. It is found that tonal sound is generated from the strong interaction between the impeller and cutoff while broadband sound is generated from the strong secondary flows along the scroll surface. To reduce the noise level, the V-shape cut-off was applied to improve the sound quality by reducing tonal noise. So the peak noise at BPF (Blade Passing Frequency) was almost reduced. The shape of flow-guide to suppress the secondary flow over the scroll surface was carefully checked. It is found that this affects flow pattern at the fan exit and reduces the broad band noise. Through this numerical and experimental study, the sound pressure level was lowered by 4dBA compared to that of the previous fan at the operating point.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.402-406
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• 2000

In the Over-The-Range, the outlet size is limited by the industrial standards. Therefor to enlarge the volume of cavity, the installation height of ventilation fan is become small, the system resistance is higher than before. For that reason, the important design variables such as the diameter of a fan, the scroll expansion angle, etc. which play the significant role on flow rate and noise, are confined. In this study, we made an experiment of the diameter of fans relation to scroll expansion angle and investigated flow rate of the length of fans in enlarged cavity volume of OTR, and then we designed the new scroll to improve the flow rate and noise level. As a result, flow rate increased to 110% compared to current scroll and the blade passing frequency of a fan is disappeared by inclined cut-off shapes.

• 한국기계가공학회지
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• 제20권10호
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• pp.119-127
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• 2021

Small drops in gas cause some problems for downstream equipments such as turbine, compressor and etc. In some cases, we are obliged to remove hazardous liquid mist from gas. In order to remove water or other liquids from the gas, there are some equipments like mesh mist eliminator and vane-plate mist eliminator. oil mist filter is a kind of liquid eliminator equipments used to remove the liquid with 1-10um droplet diameter from the gas. In this paper is determine the factors affecting the oil mist filter efficiency using CFD. length and angle of the filter were considered and the results and compare the results of the efficiency tests, showed error of less than 3%. optimum filter can remove more than 87.3% between 1 and 10um of oil mist.