Water based nanofluids for automotive applications

This paper presents a recent work on enhanced heat transfer properties of carboxylated water based nanofluids and their corrosive behavior for suitability to automotive conditions. Water mixed with Sebacic acid as carboxylate additive is dispersed with multi-walled carbon nanotubes and tested for corrosion and heat transfer characteristics. Corrosion studies made as per ASTM D 1384 show that carboxylated water dispersed with CNTs is resistant to corrosion and hence suitable for automotive environment. In addition to CNTs, carboxylated water dispersed with nano sized silver, copper and Al2O3 was also tested for corrosion performance but found to be giving considerable corrosion in automotive environment. The stability of CNT based nanofluids in terms of zeta potential is found to be good with carboxylated water compared to deionized water. Significant improvement is observed in the thermal conductivity of nanofluids dispersed with CNTs. The carboxylated water dispersed with very low mass concentration of carbon nano tubes was tested for heat transfer performance in Reynolds number range of 2500 to 6000. The inside overall heat transfer coefficient and overall heat transfer coefficient improved markedly. Also, the velocity of air and flow rate of coolant play an important role in enhancement of the overall heat transfer coefficient. The effect of enhancement of overall heat transfer coefficient on the surface area of heat exchanger and pumping power is found to be significant.