tailieunhanh - Báo cáo hóa học: " Enhancement of critical heat flux in nucleate boiling of nanofluids: a state-of-art review"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Enhancement of critical heat flux in nucleate boiling of nanofluids: a state-of-art review | Kim Nanoscale Research Letters 2011 6 415 http content 6 1 415 o Nanoscale Research Letters a SpringerOpen Journal NANO REVIEW Open Access Enhancement of critical heat flux in nucleate boiling of nanofluids a state-of-art review Hyungdae Kim Abstract Nanofluids suspensions of nanometer-sized particles in base fluids have recently been shown to have nucleate boiling critical heat flux CHF far superior to that of the pure base fluid. Over the past decade numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the effects of the primary boiling parameters. Research efforts to identify the effects of nanoparticles underlying irregular enhancement phenomena of CHF in nanofluids are then presented. Also attempts to explain the physical mechanism based on available CHF theories are described. Finally future research needs are identified. Introduction Nanofluids are a new class of nanotechnology-based heat-transfer fluids engineered by dispersing and stably suspending nanoparticles with dimensions on the order of 1-50 nm in traditional heat-transfer fluids. The base fluids include water ethylene oil bio-fluids and polymer solutions. A variety of materials are commonly used as nanoparticles including chemically stable metals . copper gold silver metal oxides . alumina bismuth oxide silica titania zirconia several allotropes of carbon . diamond singlewalled and multi-walled carbon nanotubes fullerence and functionalized nanoparticles. Nanofluids originally attracted great interest because of their abnormally enhanced thermal conductivity 1 . However recent experiments have revealed additional desirable features for thermal transfer. Key features of nanofluids that have thus far been discovered include anomalously high .