Water Flow Visualization Studies on Convective Diffusion and Layering of a Leakage in Rectangular Cavities aside a Main Flow Way
- Other Title
- リュウロ ニ セッシタ チョウホウケイ クウドウナイ ニ オケル ロウエイ ブ
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This paper deals with the characteristics of convective diffusions of a leakage, such as inflammable or harmful gas, in rectangular cavities which are aside a main flow way and ventilated from a single side. The flow visualizations for various aspect-ratios of the rectangular cavity were carried out with the water flow channel taking the difference of the density between the leakage and the main flow into consideration. The leakage was flowed out from the center on the end surface of the cavities at the velocity 0.15〜0.16U_C (U_C: main flow velocity) and flow rate about 2×10^<-5>Q (Q: main flow rate). The Froude number Fr, which was based on the width of the way, the velocity of the main flow and the difference of the density between the two fluids, was ranged from 1.1 to 3.4. The aspect ratio of the cavity D/W (W: cavity width, D: cavity depth) was widely changed in a ranged D/W≒0.1-8. The summary of the experiments of the flow visualization is as follows: 1) For D/W≒1, the ventilation flow from the main way was circulated strongly within the whole of the cavity. The leakage was also convective diffused by the recirculated flow. We thought that the problem about the ventilation in the cavity of this aspect ratio was comparably less serious than that of the other aspect ratios. 2) In a ranged 0.1<D/W<0.7, the ventilation flow was circulated within the down stream region of the cavity, while the leakage was convective diffused within the upper stream region by weak secondary recirculation flow. So the concentration of the leak matter within the upper stream region was comparably high. 3) For D/W≳2, the leak matter formed layer on the floor within the interior region of the cavity without the inlet region in which the ventilation flow was circulated. For those cavities, a local ventilation equipment will be needed to disturbed forming the layer near the end surface.
- Transactions of the Society of Heating,Air-conditioning and Sanitary Engineers of Japan
Transactions of the Society of Heating,Air-conditioning and Sanitary Engineers of Japan 14 (39), 121-131, 1989
The Society of Heating, Air-Conditioning & Sanitary Engineers of Japan