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国?交通大学机械工程研究所硕士?文介电液 FC-72 在狭窄矩形空间的池沸腾研究 Study of Pool Boiling of Dielectric Fluid FC-72 in a Narrow Rectangular Space 研究生:张妤绮指导教授 : ?定昶博士 中华民国九十三?七月介电液 FC-72 在狭窄矩形空间的池沸腾研究 Study of Pool Boiling of Dielectric Fluid FC-72 in a Narrow Rectangular Space 研究生:张妤绮Student : Yu-Chi Chang 指导教授 : ?定昶Adviser : Ding-Chong Lu 国?交通大学机械工程研究所 硕士?文AThesis Submitted to Institute of Mechanical Engineering College of Engineering National Chiao Tung University In Partial Fulfillment of the Requirements For the Degree of Master of Science In Mechanical Engineering July

2004 Hsinchu, Taiwan, Republic of China 中华民国九十三?七月 介电液 FC-72 在狭窄矩形空间的池沸腾研究 学生:张妤绮 指导教授:?定昶 国?交通大学机械工程研究所 摘要 本?文是以介电液FC-72 为工作?体在一大气压下,狭窄矩形空间的池沸 腾实验.

在狭窄矩形空间下方为面积 10mm*10mm的铜片加热面,上方为压克? 板,?端以压克?板档住,可分别调整上下板的间隙S及加热面与水平的夹角Θ, 即S=0.5mm、1mm、2mm及3mm,以及Θ=0?、45?、90?.实验目的在比较 间隙大小、加热面角?在起始过热?、核沸腾热传与?界热通?,并与开放式的 池沸腾结果比较.实验结果显示Θ=0?时,热通?低於 30kW/m2 ,S=1mm热传 系?较开放式佳.水平加热时,四种间隙的?界热通?都比开放式低很多.Θ =45?与90?时,小间隙(0.5mm)可以增强低热通?时的热传系?,且S=2mm及S=3mm其?界热通?皆超越开放式. I Study of Pool Boiling of Dielectric Fluid FC-72 in a Narrow Rectangular Space Stundent:Yu-Chi Chang Advisor:Ding-Chong Lu Institute of Mechanical Engineering National Chaio Tung University ABSTRACT The goal of this experiment is to study characteristic of pool boiling of dielectric fluid FC-72 in a narrow rectangular space under one atmosphere. The narrow rectangular space consists of a heated surface made of a smooth copper plate with

10 mm *

10 mm area and a parallel acrylic plate with two confined side edges .The gap size S and the inclination angle ? between the heated surface and the horizon are S=0.5 mm,

1 mm,

2 mm and S=3 mm, and ?=0°, 45°, 90° separately. The onset of boiling, nucleate heat transfer and critical heat transfer were studied . The results showed that for ?=0°, under low heat flux

30 kw/m2 and S=1 mm the heat transfer coefficients of this experiment were found better than those of unconfined one. For ?=0°, the critical heat fluxes for all gaps were depressed compared those of the unconfined one. For ?=45° and ?=90°, the smallest gap of 0.5 mm could enhance the heat transfer coefficients and if under low heat flux, especially for S=2 mm and

3 mm and the comes critical heat fluxes were found higher than these of the unconfined one. II 志谢踏入交大校园已届??,虽仅??却是收获丰稔,此刻即将?开 这?,心中满是感激与?舍. 本?文得以顺?完成,首先感谢恩师 ?定昶教授??多?的悉 心教导,上从研究方法的教导、观?的启迪,下至态?养成,各方面 都有深长的进步,乃至於人生目标之追求与个人潜?之提N均蒙受恩 师日常细心的开导与解惑.而恩师对学术研究之严谨精神与生活处世 之积极态?,?足为学生学习之表?. ?文口试期间,承蒙交大机械所杨文美教授与台?科技大学蔡尤 溪教授拨冗细审,并提出许多宝贵意?与殷?指正,使本?文疏?谬 误之处得以斧正.修业期间,承蒙全体?师以及博士班致广学长提供 指正与建议,尤其感谢已毕业俊贤学长在实验设备上的经验传承,使 我缩短对实验的摸?.?文进?期间,感谢同门嘉栋、伟建、家宏, 相互鼓?与安慰,及学弟的热心帮忙,谨此致上诚挚的感谢.在学期 间,感谢好友心玫、慧真、佳鸿相互鼓?与关心照顾,一起陪我?过 二?研究生生活. 最后,谨将本?文献给我的家人.感激家人在我就学期间,始终 给予我支持,让我得以无忧无虑专心致?於学业.顺?完成?文,谨 将这份成果与荣耀与您们分享! 张妤绮谨 志2004 ?7月於风城交大 目? 页次 摘要- 目?- 表目?- 图目?- 符号?明-