濃度差マランゴニ凝縮を利用する水蒸気の凝縮熱伝達促進(熱工学,内燃機関,動力など)

概要

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Although the condensation rates are reported to be less than that for pure vapors in most of previous studies concerning the condensation of binary vapor mixtures, it is known that the heat transfer enhancement can be realized by using additives to form so-called positive system (solutal Marangoni condensation). The objective of the study is to clarify the effect of ethanol mixing into steam on condensation heat transfer. First, the precise measurement was performed for wide range of ethanol concentration of vapor mixture of water and ethanol. Since the peaks of the maximum heat transfer coefficients in condensation characteristic curves were 0.12 and 0.18 MW/m^2K for vapor velocities of 0.4 and 1.5 m/s, respectively, and appeared at about 1% ethanol vapor mass fraction, it was shown that the mixing was extremely effective especially in the range of small ethanol concentration. The condensation heat transfer was enhanced about 2〜8 times as large as that of pure steam. Further, the mechanisms determining the phenomena concerning the diffusion resistance in the vapor layer and the condensate modes were also investigated.
社団法人日本機械学会の論文
2002-10-25