In this paper, forced convective heat transfer in a water based nanofluid has experimentally been compared to that of pure water in an automobile radiator. Five different concentrations of nanofluids in the range of 0.1–1 vol.% have been prepared by the addition of Al2O3 nanoparticles into the water. The test liquid flows through the radiator consisted of 34 vertical tubes with elliptical cross section and air makes a cross flow inside the tube bank with constant speed. Liquid flow rate has been changed in the range of 2–5 l/min to have the fully turbulent regime (9 × 103 < Re < 2.3 × 104). Additionally, the effect of fluid inlet temperature to the radiator on heat transfer coefficient has also been analyzed by varying the temperature in the range of 37–49 °C. Results demonstrate that increasing the fluid circulating rate can improve the heat transfer performance while the fluid inlet temperature to the radiator has trivial effects. Meanwhile, application of nanofluid with low concentrations can enhance heat transfer efficiency up to 45% in comparison with pure water.Highlights► Application of nanofluid in the car radiator has been studied experimentally. ► Heat transfer enhancement of about 45% compared to water has been recorded. ► Increasing particle concentration and velocity improves heat transfer performance.
"With 1.0 vol.% of nanoparticles, the maximum enhancements of heat transfer of the CNT–water nanofluids and Al 2 O 3 –water nanofluid were 90.76% and 52.03%, respectively higher compared to water only. Peyghambarzadeh et al.  Al 2 O 3 –water Maximum enhancement of thermal conductivity of nanofluids was 3.0% with 1.0 vol.% of Al 2 O 3 nanoparticles. However, with 1.0 vol.% of nanoparticles, maximum enhancement of heat transfer of the nanofluids was 45% when compared to water only. "
"The heat transfer enhancement was significant with the use of nanofluids. Peyghambarzadeh et al.  reported the tube side heat transfer coefficient of a car radiator by using Al 2 O 3 -water nanofluids. The heat transfer coefficient of nanofluid was evaluated for various volume concentrations (0.1–1%), mass flow rate (2–5 l/min) and the inlet temperature (37–49 C). "
[Show abstract][Hide abstract] ABSTRACT: In the present study, the convective heat transfer enhancement of CNT-water nanofluid has been studied experimentally inside an automobile radiator. Heat removal rate of the coolant flowing through the automobile radiators is of great importance for the optimization of fuel consumption. In this study, four different concentrations of nanofluids in the range of 0.15- 1 vol. % were prepared with the addition of CNT nanoparticles into water. The CNT nanocoolants are synthesized by functionalization (FCNT) and surface treatment (SCNT) method. The effects of various parameters, namely synthesis method, variation in pH values and nanoparticle concentration on the Nusselt number are examined through the experimental investigation. Results demonstrate that both nanocoolants exhibit enormous change Nusselt number compared with water. The results of functionalized CNT nanocoolant with 5.5 pH exhibits better performance compared to the nanocoolant with pH value of 6.8 and 9. The surface treated CNT nanocoolant exhibits the deterioration in heat transfer performance. In addition, Nusselt number found to increase with the increase in the nanoparticle concentration and nanofluid velocity.
Journal of Thermal Science and Engineering Applications 12/2014; 6(4). DOI:10.1115/1.4027678
"Some data were extracted from these papers in order to compare them and make an analysis of the results obtained by these authors. In the first moment, it was analyzed the heat transfer performance of the data from Peyghambarzadeh et al (2011b) and Haussein et al. (2014) in function of Reynolds number and nanoparticle volumetric concentration. How one can observe in Fig. (1) and Fig. (2), the Nusselt number increased with the Reynolds number and volumetric concentration. "
[Show abstract][Hide abstract] ABSTRACT: The research in powerful automotive engine and fuel economy has increased the interest of the cooling systems more efficient. One way to increase the efficiency of these systems is enhancing the heat exchange area, for example, adding fins in the radiator. However, this technology has reached its limits. Therefore, refrigerants with higher thermal properties have been studied. The fluids used nowadays have low thermal properties, such as water and ethylene glycol. With the advance on the research involving nanofluids, some researchers have analyzed the thermal efficiency of car radiators using nanofluid as refrigerants. This article aims to review some of these researches and compare the results obtained in them.
15th Brazilian Congress of Thermal Sciences and Engineering, Belém-PA, Brasil; 10/2014
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