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: Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow | Teng et al. Nanoscale Research Letters 2011 6 488 http content 6 1 488 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow Tun-Ping Teng1 Yi-Hsuan Hung1 Tun-Chien Teng2 and Jyun-Hong Chen1 Abstract This study analyzes the characteristics of alumina Al2O3 water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3 water nanofluid produced by the direct synthesis method at three different concentrations and wt. . The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample temperatures 20-60 C and then used the nanofluid in an actual air-cooled heat exchanger to assess its heat exchange capacity and pressure drop under laminar flow. Experimental results show that the nanofluid has a higher heat exchange capacity than water and a higher concentration of nanoparticles provides an even better ratio of the heat exchange. The maximum enhanced ratio of heat exchange and pressure drop for all the experimental parameters in this study was about 39 and respectively. In addition to nanoparticle concentration the temperature and mass flow rates of the working fluid can affect the enhanced ratio of heat exchange and pressure drop of nanofluid. The cross-section aspect ratio of tube in the heat exchanger is another important factor to be taken into consideration. Keywords alumina Al2O3 heat exchange capacity laminar flow nanofluid pressure drop Introduction As technology and energy products require higher standards of function and performance the problem of heat dissipation is becoming a significant issue in many appliances. Using a working fluid with high heat transfer performance is a topic worthy of research as it may solve this
