日本語フィールド
著者：有馬博史，岡本明夫，松尾伸彦，池上康之 読み: アリマヒロフミ、オカモトアキオ、マツオノブヒコ、イケガミヤスユキ題名：微細凹凸面を用いたプレート蒸発器におけるアンモニアの沸騰伝熱促進発表情報：佐賀大学海洋エネルギー研究センター報告OTEC 巻: 14 ページ: 11-19キーワード：Heat transfer enhancemnet, Ammonia, Plate heat exchanger, Grooved surface, Emplycal correlation概要：抄録：The small thermal energy conversion, such as Ocean thermal energy conversion (OTEC) is expected to be the new renewable energy. Since small thermal energy conversion cycles have low thermal efficiency, these systems use a plate type heat exchanger, and ammonia or ammonia/water mixture as a working fluid. Then, in order to more improve their cycle efficiency, it is necessary to improve the efficiency of plate heat exchanger and study the characteristic of boiling heat transfer of ammonia or ammonia/water on plate heat exchanger.
Therefore, in order to examine the boiling heat transfer enhancement of ammonia on plate evaporator, we studied about the effect of heat transfer surface condition using treated heat transfer surface with micro grooves and flat surface for vertical plate evaporator. In this study, measurements of local boiling heat transfer coefficients on forced convection were performed for pure ammonia on both surface type plate heat exchangers in a range of mass flux (2 - 7.5 kg/m2 s), heat flux (10 - 20kW/m2), and pressure (0.7 - 0.9 MPa).
The result shows that, the local boiling heat transfer coefficient of grooved surface was larger than that of flat surface. In addition, in case of grooved surface, heat transfer coefficient increased with an increase mass flux. Especially the effect of heat transfer enhancement using grooved surface appeared notably in the nucleate boiling region. On the other hand, an empirical correlation was derived for the local boiling heat transfer coefficient using the Lockhart-Martinelli parameter. This correlation can predict the heat transfer coefficient with +/-25% or less accuracy for all of the present conditions.英語フィールド
Author：Hirofumi Arima, Akio Okamoto, Nobuhiko Matsuo, Yasuyuki IkegamiTitle：Boiling heat transfer enhancement for ammonia using micro grooved surface on plate evaporatorAnnouncement information:Report of Institute of Ocean Energy, Saga University,OTEC Vol: 14 Page: 11-19Keyword：Heat transfer enhancemnet, Ammonia, Plate heat exchanger, Grooved surface, Emplycal correlationAn abstract：The small thermal energy conversion, such as Ocean thermal energy conversion (OTEC) is expected to be the new renewable energy. Since small thermal energy conversion cycles have low thermal efficiency, these systems use a plate type heat exchanger, and ammonia or ammonia/water mixture as a working fluid. Then, in order to more improve their cycle efficiency, it is necessary to improve the efficiency of plate heat exchanger and study the characteristic of boiling heat transfer of ammonia or ammonia/water on plate heat exchanger.
Therefore, in order to examine the boiling heat transfer enhancement of ammonia on plate evaporator, we studied about the effect of heat transfer surface condition using treated heat transfer surface with micro grooves and flat surface for vertical plate evaporator. In this study, measurements of local boiling heat transfer coefficients on forced convection were performed for pure ammonia on both surface type plate heat exchangers in a range of mass flux (2 - 7.5 kg/m2 s), heat flux (10 - 20kW/m2), and pressure (0.7 - 0.9 MPa).
The result shows that, the local boiling heat transfer coefficient of grooved surface was larger than that of flat surface. In addition, in case of grooved surface, heat transfer coefficient increased with an increase mass flux. Especially the effect of heat transfer enhancement using grooved surface appeared notably in the nucleate boiling region. On the other hand, an empirical correlation was derived for the local boiling heat transfer coefficient using the Lockhart-Martinelli parameter. This correlation can predict the heat transfer coefficient with +/-25% or less accuracy for all of the present conditions.