EXPERIMENTAL ANALYSIS AND SIMULATION STUDY OF AN AUTOMOBILE RADIATOR WITH NANOFLUIDS

A nanofluid is the suspension of nanoparticles in a base fluid. Nanofluids are promising fluids for heat transfer enhancement due to their anomalously high thermal conductivity. The thermal conductivity enhancement mechanisms of nanofluids have not been fully understood yet. In the first part of this study, a detailed literature review about the thermal conductivity of nanofluids is performed. Experimental studies are discussed in terms of the effects of some parameters such as particle volume fraction, particle size, and temperature on the thermal conductivity of nanofluids. Enhancement mechanisms proposed to explain nanofluid thermal conductivity are also summarized. Research about the forced convection of nanofluids is important for the practical application of nanofluids in heat transfer devices. Recent experiments showed that heat transfer enhancement of nanofluids exceeds the thermal conductivity enhancement of nanofluids. This extra enhancement might be explained by thermal dispersion, which occurs due to the random motion of nanoparticles in the flow. In order to examine the validity of a thermal dispersion model available in the literature, hydrodynamically fully developed, thermally developing laminar flow of Al 2 O 3 /water nanofluid inside a straight circular tube radiator under constant wall temperature and constant wall heat flux boundary conditions is experimentally analyzed. Results are compared with experimental and numerical data in the literature and good agreement is observed especially with experimental data. It is clear that the nanofluids increases the heat transfer and it is justified by the experimental work using an automobile radiator.