Heat Exchange Performances of Sheet Type Heat Exchanger submerged in Water Flow and Installation Method to an Agriculture Irrigation Canal
| Jazyk: | japonština |
|---|---|
| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | 農研機構研究報告 農村工学研究部門 = Bulletin of the NARO, Rural Engineering. 3:29-42 |
| ISSN: | 2432-7883 |
| Popis: | The sheet type heat exchanger was set in the full-scale hydraulic model in imitation of an agriculture irrigation canal and the experimental data of heat exchange performances were collected under the different conditions of hydraulic and installation methods. The heat exchange performances were evaluated by heat transfer coefficient that divided a square measure of a heat exchange capable by the heat transfer coefficient, which is an amount of heat transfer between the heat transfer liquid and the surrounding water flow, per a unit temperature difference between them and per a unitarea of heat exchanger. The maximal heat transfer coefficient in water flow showed 0.255kW/(K･m2). The performance was higher than 0.017kW/(K･m2) of the same exchanger installed underground and 0.01kW/(K･m2) of slinky-type heat exchanger installed underground. The heat transfer coefficient was increased with increase in the speed in water flow, and there was little influence by the increase in hear transfer liquid. Sheet type heat exchanger integrated with reticulated expanded metal was devised to prevent the damage from trash and the sheet from being deflected. A high heat transfer coefficient was provided by being unified with sheet type heat exchanger integrated with reticulated expanded metal although it decreased by approximately 10%. The heat transfer coefficient on 110mm gap between sheet and side wall was the biggest and more than heat transfer coefficient 0.21kW/(K･m2) were measured. The blocking board installed at the edge of upper reaches of the expanded metals was effective from the viewpoint of prevention of trash adhesion. 農業用水路を模した実規模水理模型にシート状熱交換器を設置して，水理条件や設置方法の違いによる熱交換特性を計測した。熱交換特性は，熱交換器と流水の温度差 1K 当たりの熱交換量を熱交換可能な面積で除した値である熱通過率を用いて評価した。流水条件下での最大の熱通過率は 0.255kW/(K･m2)で，土中設置の 0.017kW/(K･m2)，スリンキー式の 0.01kW/(K･m2)よりも高い性能を示した。熱通過率は水路内流速の増加に伴って増加し，熱媒流量の増加による影響は少ない。熱交換器を網目状のエキスパンドメタルと一体化させて，流下物から保護し撓みなく設置する方法を考案した。エキスパンドメタルと一体化することで熱通過率は約 10％低下するものの，高い熱通過率が得られた。側壁間隔との関係では 110mm の時の熱通過率が最も大きく，熱通過率 0.21kW/(K･m2)以上が計測された。上流端のエキスパンドメタルに遮断板を設置することはゴミ付着防止の観点から有効である。 |
| Databáze: | OpenAIRE |
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