Effect of nanofluids on heat transfer enhancement in automotive cooling circuits

Continuous technological development in automotive industries has increased the demand for high efficiency engines. Optimizing design and size of a radiator in order to reduce a vehicle weight is a requirement for making the world green. Using of fins is one of the techniques to increase the cooling rate of the radiator. However, traditional approach of enhancing the cooling rate by using fins and microchannels has already showed to their limit. Furthermore, heat transfer fluids such as water and ethylene glycol have very low thermal conductivity. As result there is an urgency for new and innovative heat transfer fluids for increasing heat transfer rate in an automotive cooling circuit. Nanofluids represent potential substitute of conventional coolants in engine cooling system. In this paper a cooling circuit is modelled in TRNSYS (version 17) and investigated in transient regime. The circuit is composed by a heating system, a pump and a heat exchanger. The heat exchanger represents a car radiator in the circuit. The nanofluid is a mixture of water and Al2O3 nanoparticles. The study is conducted for three different engine operating conditions (Low, Medium and High) and different volume concentrations of nanoparticles.