tailieunhanh - Báo cáo hóa học: " Discussion on the thermal conductivity enhancement of nanofluids"

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: Discussion on the thermal conductivity enhancement of nanofluids | Xie et al. Nanoscale Research Letters 2011 6 124 http content 6 1 124 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Discussion on the thermal conductivity enhancement of nanofluids Huaqing Xie Wei Yu Yang Li Lifei Chen Abstract Increasing interests have been paid to nanofluids because of the intriguing heat transfer enhancement performances presented by this kind of promising heat transfer media. We produced a series of nanofluids and measured their thermal conductivities. In this article we discussed the measurements and the enhancements of the thermal conductivity of a variety of nanofluids. The base fluids used included those that are most employed heat transfer fluids such as deionized water DW ethylene glycol EG glycerol silicone oil and the binary mixture of DW and EG. Various nanoparticles NPs involving Al2O3 NPs with different sizes SiC NPs with different shapes MgO NPs ZnO NPs SiO2 NPs Fe3O4 NPs TiO2 NPs diamond NPs and carbon nanotubes with different pretreatments were used as additives. Our findings demonstrated that the thermal conductivity enhancements of nanofluids could be influenced by multi-faceted factors including the volume fraction of the dispersed NPs the tested temperature the thermal conductivity of the base fluid the size of the dispersed NPs the pretreatment process and the additives of the fluids. The thermal transport mechanisms in nanofluids were further discussed and the promising approaches for optimizing the thermal conductivity of nanofluids have been proposed. Introduction More efficient heat transfer systems are increasingly preferred because of the accelerating miniaturization on the one hand and the ever-increasing heat flux on the other. In many industrial processes including power generation chemical processes heating or cooling processes and microelectronics heat transfer fluids such as water mineral oil and ethylene glycol always play vital roles. The poor heat transfer