Control of Heat Transfer and Defrostings with Fluidized Beds

流化床传热和除霜的控制

• 批准号: 06044018
• 负责人: AIHARA Toshio
• 金额: $ 3.84万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044018/
• 关键词: Fluidized bed; Impinging jet; Heat-transfer control; Frosting control; Cooled tube array; 冷却官群

In the cases where conventional finned-tube heat exchangers are used as evaporators in heat pump systems and LNG-gasification systems, moisture in humid air freezes and forms a thick frost layr on the fin surfaces, which reduces the heat transfer, increases the pressure loss, and finally results in choking of the evaporatores. Thus development of frost-free evaporators is an important and urgent research subject. The present research project has been performed to study heat and mass transfer characteristics of impinging jet-type fluidized bed and its defrosting characteristics. The obtained results are useful to establish a fluidized-bed heat exchanger which is effective for defrosting.Results of the Joint ResearchIn Tohoku University, the following experimental studies were performed :(1) Study on local heat transfer and frosting characteristics of cold tubes in single-phase impinging jets.(2) Study on defrosting mechanism of a very shallow fluidized bed, measurement of particle's con … More tact frequency onto the tube surface, and observation of the behavior of particles on the tube surface.(3) Study on heat transfer characteristics of cold tubes under defrosting by particle impingement.In Hokkaido University the following experimental studies were performed :(1) Study on heat transfer charactersistics of impinging-jet type fluidized ged. Especially the effect of fluidizing particles on heat transfer in a powder-mixed fluidized bed.(2) Study on freezing and continuous production characteristics of liquid ice by use of the fluidized bed.(3) Study on frosting characteristics of a vertical cooled plate and a horizontal cooled tube array immersed in a fluidized bed.(4) Study on melting heat transfer characteristics of a horizontal cooled tube array immersed in liquid ice.In Technical University, Vienna, theoretical study on formation process of particle-gas jets and their impingement onto tube surface was performed especially for the cornice-type distributor, utilized in Tohoku University.By joining these results of the above-mentioned studies, an potimum design method for impinging-jet type fluidized bed has been established. Also the heat-transfer and defrosting characteristics and the control theory for them were clarified, which is useful for practical applicatios. Less

在热泵系统和液化天然气气化系统中使用传统的翅片管式换热器作为蒸发器时，湿空气中的水分冻结并在翅片表面形成厚厚的霜层，从而降低了传热，增加了压力损失，最终导致蒸发器堵塞。因此，开发无霜蒸发器是一项重要而紧迫的研究课题。本文对撞击射流床的传热传质特性及其除霜特性进行了研究。研究结果：(1)研究了冷管在单相冲击射流中的局部换热和结霜特性；(2)研究了极浅层沸腾床的除霜机理，测定了颗粒的…在北海道大学开展了以下实验研究：(1)冲击射流流态化换热特性的研究。(2)利用流态化床对液冰的冻结和连续生产特性进行了研究。(3)研究了垂直冷却平板和水平冷却管阵在沸腾床中的结霜特性。(4)对水平冷却管阵在液体冰中的熔化换热特性进行了研究。在维也纳工业大学，特别是针对东北大学使用的封隔式分布器，对颗粒-气体射流的形成过程及其对管子表面的冲击进行了理论研究。结合上述研究结果，建立了撞击射流型沸腾床的优化设计方法。阐明了其换热、除霜特性及控制原理，对实际应用具有一定的指导意义。较少

项目成果

T.Aihara: "Heat Transfer and Defrosting Characteristics of a Horizontal Tube Array Evaporator Immersed in a Very Shallow Fluidized Bed" Proc. CFCs, The DAY AFTER International Conference. 599-606 (1994)

T.Aihara：“浸没在很浅流化床中的水平管阵列蒸发器的传热和除霜特性”Proc。

小原拓: "水平着霜官群の衝突噴流熱伝達" 空気調和・衛生工学会論文集. 50号(印刷中). (1995)

Taku Ohara：“水平结霜官员的撞击射流的传热”，空调和卫生工程师学会论文集，第 50 期（出版中）。

相原 利雄: "極浅層流動層中におかれた水平冷却管群の伝熱と除霜特性に関する研究" 日本機械学会論文集(B編). (印刷中). (1996)

Toshio Aihara：“放置在极浅流化床中的水平冷却管的传热和除霜特性的研究”日本机械工程师学会论文集（B 版）（1996 年出版）。

S.Fukusako: "Continuous Production Characteristics of Liquid Ice by Use of a Fluidaized Bed" ASME Paper,HTD. 284. 137-144 (1994)

S.Fukusako：“使用流化床连续生产液态冰的特性”ASME Paper，HTD。

S.Fukusako: "Rapid Heat Transfer Manipulation of Fine Powder by Use of a Fluidized Bed" Proc. of 10th Internatiional Heat Transfer Conference. 5. 255-260 (1994)

S.Fukusako：“使用流化床对细粉末进行快速传热操作”Proc。