This study focused on the evaluation of TiO2 nanofluid coolant for automobile engine cooling applications. It was observed that, about 3% of thermal conductivity enhancement and above 10% convective heat transfer enhancement could be achieved with the usage of 1.0 wt.% TiO2 nanofluid coolant compared to base coolant without nanoparticles. More importantly, corrosion-inhibiting properties of TiO2 nanofluid coolant were investigated, which indicated that the nanofluid coolant possess the characteristics of a qualified engine coolant should have. The evaluation results showed that the nanofluid coolant could be a promising engine coolant for automobiles.

The structure of cast iron specimen and the temperature control unit of the engine coolant ultrasonic cavitation apparatus were improved in this paper. The broken problem of cast iron specimen was solved by split-structure design, which also solved the loose binding problem between specimen and sonotrode. The temperature control unit included a beaker with water circulating jacket, water bath, circulating pump and connection hose. The temperature control unit overcame the difficulty of the temperature control of test coolant solution. More important, the temperature control inside the soundproof box was realized, which avoided the effect of ultrasonic vibration noise on the health of operator. The unit has the characteristics of simple, practical and easy to use.