한국해양대학교

Detailed Information

Metadata Downloads

작동압력변화에 따른 마이크로 채널내 대류비등 열전달

DC Field Value Language
dc.contributor.author 윤태영 -
dc.date.accessioned 2017-02-22T06:55:13Z -
dc.date.available 2017-02-22T06:55:13Z -
dc.date.issued 2005 -
dc.date.submitted 56823-03-29 -
dc.identifier.uri http://kmou.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002175734 ko_KR
dc.identifier.uri http://repository.kmou.ac.kr/handle/2014.oak/10019 -
dc.description.abstract As faster computing speed has been increasingly demanded, the industry has been seeking for a newer cooling device with substantially improved cooling performance. One of the plausible and practical solutions can be a closed-loop with microchannels embedded within the chip. Both single phase convective heat transfer and two-phase flow boiling can be considered as the heat transfer mode in the microchannels, the latter having an advantage of larger temperature difference. Given the maximum allowed temperature in the chip for the safe and reliable operation and water being the fluid, the operating pressure should be subatmospheric for flow boiling heat transfer mode, i.e., 31 kPa for 70℃ of inlet water temperature. The objective of the present work is to experimentally investigate the effect of operating pressure on flow boiling heat transfer and pressure drop in a single microchannel. The experimental apparatus consists mainly of Peristaltic pump, preheater, test section, and vacuum chamber for control of operating pressure. De-ionized water is used as the working fluid. The test section is a round microchannel of 310 μm inside diameter, made of 304 stainless steel. The experiment has been performed for the conditions of heat flux from 35 to 86 kW/m2, mass flux from 203 to 305 kg/m2s ( 168 to 254 of liquid Reynolds numbers), and the average operating pressure from 11 to 19 kPa. The measured flow boiling heat transfer coefficients in the microchannel were in the range of 3 to 27 kW/m2 and the experimental showed that the flow boiling heat transfer coefficients in microchannel were affected by the wall heat flux and the operating pressure, while slightly dependent on mass flux. One of the major findings was that the trend of the variation of the heat transfer coefficient in terms of wall heat flux (or vapor quality) was largely changed by the operating pressure. At the lower operating pressure (~ 11 kPa) the heat transfer coefficient increased as the wall heat flux increased, but at the higher operating pressure (~19 kPa ) it decreased as the wall heat flux increased. The cause of such opposing trends by the operating pressure can be attributed to the role of the liquid film in the flow boiling pattern in microchannels and the variation of relevant physical properties such as latent heat of vaporization. -
dc.description.tableofcontents Abstract 사용기호 표목차 그림목차 제 1 장 서 론 1 1.1 연구배경 1 1.2 연구목적 2 제 2 장 선행연구 고찰 3 2.1 서론 3 2.2 대류비등열전달 5 2.3 미니 / 마이크로 채널 11 2.4 미니 / 마이크로 채널에서의 단상대류열전달에 대한 실험적 연 13 2.5 미니 / 마이크로 채널에서의 대류비등 열전달 18 2.5.1 미니 채널(수력직경 1mm 이상)에서의 대류비등 열전달계수의 변화에 대한 실험적 연구 18 2.5.2 미니 / 마이크로 채널(수력직경 1mm 이하)에서의 대류 비등열전달 계수의 변화에 대한 실험적 연구 20 2.5.3 미니 / 마이크로 채널에서의 대류비등열전달 상관식 22 2.6 선행연구 고찰 요약 25 제 3 장 실험장치 및 실험방법 40 3.1 실험장치 및 계측 40 3.2 실험오차 분석 44 3.2.1 온도측정 44 3.2.2 압력측정 45 3.2.3 질량속도(Mass flux) 46 3.2.4 열유속(Heat flux) 47 3.3 실험방법 49 3.3.1 단상실험 49 3.3.2 이상(Two-Phase) 실험 49 제 4 장 단상 실험결과 및 고찰 60 4.1 실험조건 및 데이터 처리 60 4.2 실험결과 61 제 5장 이상 실험결과 및 고찰 64 5.1 실험조건 64 5.2 데이터 처리 65 5.3 질량유속 및 열유속 변화에 따른 대류비등열전달 계수 66 5.4 관내 평균압력변화에 따른 증발열전달계수 변화 69 5.5 압력강하 72 제 5 장 결 론 81 참고문헌 83 -
dc.language kor -
dc.publisher 한국해양대학교 대학원 -
dc.title 작동압력변화에 따른 마이크로 채널내 대류비등 열전달 -
dc.title.alternative Effect of Operating Pressure on Flow Boiling Heat Transfer in a Microchannel -
dc.type Thesis -
dc.date.awarded 2005-02 -
dc.contributor.alternativeName Tae-Young Yoon -
Appears in Collections:
냉동공조공학과 > Thesis
Files in This Item:
000002175734.pdf Download

Items in Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse