タンク内ガス置換に及ぼす船殼構造部材の影響について

概要

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This paper shows the results of model tests and actual ship test concerning gas diffusion in tanks. To discuss gas diffusion in the space surrounded by large hull structual members, especially in the so-called "dead space", the authors carried out model tests in a one-thirtieth model tank, in which the size of holes on a horizontal girder was changeable. To minimize the effect of taking the test fluid out of a tank for measuring, hot/cold water was chosen as a test fluid instead of gas. And then, gas diffusion in an actual ship was estimated using the similarity between gas diffusion and heat transfer, which was confirmed by gas freeing/inerting test on an actual ship. The followings are concluded. (1) If the size of holes on a horizontal girder is large enough to pass the jet flow, the horizontal girder does not effect to gas diffusion in tanks. (2) Side holes on a horizontal girder near bulkhead wall shorten the time of gas change in tanks. But, the additional side holes are unnecessary on actual ships having suitable drain holes on a horizontal girder. (3) It is effective to increase the flow velocity by reducing the inlet diameter, for uniform gas diffusion, if the flow rate of inlet gas is constant. (4) The equation φ=e^<-τ> agrees well with results of the tests, if the flow velocity in the axial direction of jet is not less than 1.3m/s at the tank bottom.
社団法人日本船舶海洋工学会の論文
1978-08-15