Enhancing diesel engine cooling efficiency: A comprehensive numerical study on nanofluid coolants with exergy and economic analysis

This research focuses on improving the efficiency of four-stroke diesel engines, widely used in land transport. The study looks at how using nanofluids and different coolant combinations can impact thermophysical properties, such as convective heat transfer coefficient, Nusselt number, and entropy values. The Mercedes-Benz OM502 v8 2023 engine is used in the study. The goal is to improve radiator cooling processes and achieve economic savings. Causing more improvements in nanofluids thermophysical specifications according to available literature has led us to consider titania (TiO2), silica (SiO2), and alumina (Al2O3) nanoparticles. Nanofluids with the mentioned compositions, besides nanoparticles with 0.2%–0.8% vol. concentrations, have been studied, and eventually, the most efficient nanofluid composition has been selected as the optimal coolant. The validity of the utilized numerical technique is verified by comparing the method output with the Mercedes-Benz OM502 V8 2023 engine catalog. Results of our numerical studies show a 75.1% and 128.1% improvement in heat transfer rate along with a coolant temperature drop at the outlet by 23.8 °C and 21.4 °C at coolant's inlet temperatures of 85 °C and 95 °C. Furthermore, economic analyses have demonstrated that the use of optimal coolant composition can yield annual cost savings of approximately $2700.