Experimental and numerical study on cooling system waste heat recovery for engine air preheating by ternary hybrid nanofluid

Abstract

The performance characteristics of a car radiator with new radiator coolants of ternary hybrid nanofluid of 0.12% vol. fraction (Al2O3-CuO-TiO2/water) and water is experimentally investi-gated. Waste heat from the mentioned radiator coolants has been treated as the preheating intake air for a single-cylinder diesel engine, and the performance was evaluated and compared. Furthermore, the numerical analyses were processed through a mixture model and homogeneous model (single-phase) approach techniques. However, the ternary hybrid nanofluid (THNF) showed a 14% higher heat transfer coefficient at 8 Lpm, and the mixture model predicted a 5% better result than the single-phase approach. The preheating condition in the engine enhances the engine performance, and a 50% engine load reveals a maximum enhancement of 12.54% in brake thermal efficiency at 46.5°C, with a fuel-saving rate of 14.28% at 8 Lpm. Also, a variation in coolant flow rate (CFR) and air velocity for a radiator influences positive engine performance. Moreover, the engine energy distribution through the pie chart revealed that the heat transfer rate for THNF increased by 5% at an air velocity of 0.75 m/s. Therefore, the use of waste heat through THNF radiator coolants for air preheating in engines achieved the enhancement in fuel consumption rate for the same power generation. © 2021 Begell House Inc.. All rights reserved.