tailieunhanh - Báo cáo hóa học: " Enhancements of thermal conductivities with Cu, CuO, and carbon nanotube nanofluids and application of MWNT/water nanofluid on a water chiller syste"

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: Enhancements of thermal conductivities with Cu, CuO, and carbon nanotube nanofluids and application of MWNT/water nanofluid on a water chiller syste | Liu et al. Nanoscale Research Letters 2011 6 297 http content 6 1 297 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Enhancements of thermal conductivities with Cu CuO and carbon nanotube nanofluids and application of MWNT water nanofluid on a water chiller system MinSheng Liu1 Mark ChingCheng Lin2 and ChiChuan Wang3 Abstract In this study enhancements of thermal conductivities of ethylene glycol water and synthetic engine oil in the presence of copper Cu copper oxide CuO and multi-walled carbon nanotube MWNT are investigated using both physical mixing method two-step method and chemical reduction method one-step method . The chemical reduction method is however used only for nanofluid containing Cu nanoparticle in water. The thermal conductivities of the nanofluids are measured by a modified transient hot wire method. Experimental results show that nanofluids with low concentration of Cu CuO or carbon nanotube CNT have considerably higher thermal conductivity than identical base liquids. For CuO-ethylene glycol suspensions at 5 vol. MWNT-ethylene glycol at 1 vol. MWNT-water at vol. and MWNT-synthetic engine oil at 2 vol. thermal conductivity is enhanced by 17 and 30 respectively. For Cu-water at vol. thermal conductivity is increased by . The thermal conductivity improvement for CuO and CNT nanofluids is approximately linear with the volume fraction. On the other hand a strong dependence of thermal conductivity on the measured time is observed for Cu-water nanofluid. The system performance of a 10-RT water chiller air conditioner subject to MWNT water nanofluid is experimentally investigated. The system is tested at the standard water chiller rating condition in the range of the flow rate from 60 to 140 L min. In spite of the static measurement of thermal conductivity of nanofluid shows only increase at room temperature relative to the base fluid at volume fraction of vol.