알루미나 나노유체의 열전달 특성에 관한 실험적 연구
Experimental investigation of heat transfer characteristics of alumina nanofluid
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초록
나노유체란 유체 내에 금속 또는 비금속성 나노 크기의 입자를 분산시킨 것으로서 열전달율을높이기 위해 다양한 곳에서 사용되어진다. 본 논문에서는 50 nm 크기의 알루미나를 증류수에 분산시켜 농도 및 유속에 따른 기본적인 열전달 특성을 알아보고자 하였다. 실험 결과 알루미나 나노유체의 농도가 증가할수록 평균 및 국소 열전달 계수가 증가하는 경향을 보였다. 또한 X/D=50~120 구간에서 6 Wt%의 나노유체의 국소 열전달 계수값이 증류수와 비교하였을 때 최대 37~46% 정도 높게 나타났다. 6 Wt% 농도에서 레이놀즈수가 1100~1300일 때 평균 열전달 계수가 증류수에 비해 큰폭으로 증가함을 확인하였다.
Abstract
Nanofluids are suspensions of metallic or nonmetallic nano powders in base liquid and can be employed to increase heat transfer rate in various applications. In this research the heat transfer characteristics has been experimented by alumina(50 nm)/water nano-fluids. Experimental results showed that the increasing the concentration of alumina nanofluids local and average heat transfer coefficient increased. The local heat transfer coefficient of 6 Wt% nanofluid was increased 37~46% than water at X/D=50~120. The average heat transfer coefficient of 6 Wt% nanofluid was rapidly increased than water at Reynolds number 1100~1300.
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