冷媒R-245fa於氟化石墨烯表面改質鰭管之冷凝熱傳性能研究;Condensation Heat Transfer of Refrigerant R-245fa on Fluorinated Graphene Coating Fin-Tubes

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Title:	冷媒R-245fa於氟化石墨烯表面改質鰭管之冷凝熱傳性能研究;Condensation Heat Transfer of Refrigerant R-245fa on Fluorinated Graphene Coating Fin-Tubes
Authors:	陳禹霖;Chen, Yu-Lin
Contributors:	機械工程學系
Keywords:	冷凝熱傳;鰭管;石墨烯;氟化石墨烯;R-245fa;冷凝;Condensation heat transfer;Fin Tube;Graphene;Fluorinated Graphene;R-245fa;condensation
Date:	2020-01-06
Issue Date:	2020-06-05 17:42:14 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究使用低表面張力流體冷媒R-245fa作為工作流體，測量R-245fa在鰭片間距為2.0、1.5、1.0和0.5毫米的鰭管上的熱傳性能。並且使用化學氣相沉積法(CVD)在鰭片間距為2.0、1.5、1.0和0.5毫米的鰭管上塗佈石墨烯和氟化石墨烯，希望藉由石墨烯和氟化石墨烯低表面能之特性來提升工作流體R-245fa的靜態接觸角，進而降低R-245fa在鰭管上的表面張力，來提升冷凝熱傳係數。結果顯示R-245fa在無塗佈表面、石墨烯表面和氟化石墨烯表面的靜態接觸角分別為：6.0o、13.2o和20.1o。並且在0.5毫米鰭管的熱傳性能，石墨烯和氟化石墨烯分別能提升約35%和50%的熱傳性能；但是在鰭片間距1.0毫米的鰭管，石墨烯和氟化石墨烯僅能分別提升熱傳性能約3.5%和17%，並且隨著鰭片間距增加，石墨烯和氟化石墨烯的提升熱傳性能的幅度也隨之變小。;This study provides an experimental investigation on the condensation heat transfer performance of R-245fa on fluorinated graphene coating, graphene coating and non-coating fin tubes. Four finned tubes with fin space of 0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm were testes. Graphene and fluorinated graphene were coated on the fin tube surface by the method of chemical vapor depositions (CVD). The contact angles of non-coating, graphene coating and fluorinate are 6.0o, 13.2o and 20.1o with R-245fa. Owing to the liquid-surface contact angle altered by the graphene and fluorinated coating, the condensate drained within the fin space reduced especially for the smallest fin space tube. The test results show that the condensation heat transfer coefficients on graphene coating and fluorinated graphene coating tubes are up to 35% and 50% higher than those on coating tube on 0.5 mm fin space tube. For larger fin space tubes, the effect of surface coating reduced. The enhancement on graphene coating and fluorinated graphene coating tubes reduced to 3.5% and 17% in comparing to non-coating tube.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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