OS9-07 マイクロ蒸気インジェクタへの不凝縮性ガスの影響(OS9 動力エネルギーシステムにおける熱流動)

概要

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Effect of non-condensable gas on a micro steam injector (MSI) to obtain a vacuum was experimentally studied. The MSI used in this study had a nozzle of approximately 3mm in diameter to inject a water jet in the mixing region with a supersonic steam flow. When a pure steam was used in the MSI, the high vacuum condition was obtained. However when the mass fraction of air included in the steam was larger than a certain value, the MSI became unstable and the vacuum condition could not be obtained. It is considered that the malfunction of MSI is due to the instability triggered with the uncondensed steam at the throat in downstream of the mixing region resulted with the degraded condensation behavior. The water nozzle was considered to be a key component to mitigate the effect of non-condensing gas. Two kinds of water nozzle whose flow area were round and star shapes were used in present experiment. The star-shaped nozzle where the increased surface area could be expected to compensate the degradation of condensation heat transfer failed to improve the malfunction of MSI with the non-condensing gas. It was pointed out that the malfunction did not depend only on the degradation of condensing heat transfer.
社団法人日本機械学会の論文
2005-06-28