日本語フィールド
著者：三島 文也，有馬 博史，小山 幸平，岡本 明夫，池上 康之題名：アンモニア強制対流のプレート式蒸発器における沸騰様相発表情報：佐賀大学海洋エネルギー研究センター報告OTEC 巻: 16 ページ: 19-32キーワード：Ammonia, Visualization, Heat Transfer Coefficient, Plate Evaporator概要：抄録：OTEC is one of the renewable energy using small temperature difference between surface and deep sea water, which is expected to be the countermeasures against global warming problem. In addition, such renewable energy attracts attention as what replaces nuclear power generation. However, since it is inefficient and an initial investment is expensive, OTEC is not yet put in practical use. Therefore, the improvement the efficiency of heat exchanger is important for implementation. In this study, the visualization of ammonia forced convection on plate evaporator has been performed to analyze the boiling feature and the relationship between thermal equilibrium vapor quality and void fraction. The visualization was used 250fps high-speed video camera and ammonia flow patterns were observed on three sight glasses. At the same time, measurements of local heat transfer coefficients were performed at a range of mass flux (7.5-15 kg/(m2 s)), heat fluxes (15-25 kW/m2), and pressures (0.7-0.9 MPa). The result shows that the void fraction increases with an increase in thermal equilibrium vapor quality. However, it is found that the tendency is close to drift flux model proposed by Zuber et al. instead of homogeneous flow model.英語フィールド
Author：Fumiya MISHIMA, Hirofumi ARIMA, Kohei KOYAMA, Akio OKAMOTO, Yasuyuki IKEGAMITitle：Boiling Feature on Forced Convection of Ammonia on Plate EvaporatorAnnouncement information:Report of Institute of Ocean Energy, Saga University,OTEC Vol: 16 Page: 19-32Keyword：Ammonia, Visualization, Heat Transfer Coefficient, Plate EvaporatorAn abstract：OTEC is one of the renewable energy using small temperature difference between surface and deep sea water, which is expected to be the countermeasures against global warming problem. In addition, such renewable energy attracts attention as what replaces nuclear power generation. However, since it is inefficient and an initial investment is expensive, OTEC is not yet put in practical use. Therefore, the improvement the efficiency of heat exchanger is important for implementation. In this study, the visualization of ammonia forced convection on plate evaporator has been performed to analyze the boiling feature and the relationship between thermal equilibrium vapor quality and void fraction. The visualization was used 250fps high-speed video camera and ammonia flow patterns were observed on three sight glasses. At the same time, measurements of local heat transfer coefficients were performed at a range of mass flux (7.5-15 kg/(m2 s)), heat fluxes (15-25 kW/m2), and pressures (0.7-0.9 MPa). The result shows that the void fraction increases with an increase in thermal equilibrium vapor quality. However, it is found that the tendency is close to drift flux model proposed by Zuber et al. instead of homogeneous flow model.