Effect of CNT and Al 2 O 3 -CNT hybrid nano-additive in water-emulsified fuels on DICI engine energetic and exergetic performances

In this study, an experimental investigation of the engine performance parameters has been performed for the 5% water-emulsified fuel, 50 ppm CNT, and 50 ppm Al2O3-CNT (25 ppm each) hybrid nano-additive fuels on the DICI engines with differing engine speed and load. The parameters BTE, exergy destruction rate (EDR), exergy efficiency, and engine sustainability have escalated with enhancing engine speed and load for every fuel sample. The BTE of the DICI engine at 1500 rpm speed and 5.6 kW of engine power with 5% water-emulsified fuel, 5% water-emulsified-CNT, and 5% water-emulsified fuel—Al2O3-CNT nano-fuel is 1.49%, 2.86%, and 3.07% higher, and the exergy efficiency is 1.85%, 4.16%, and 5.21% higher than pure diesel. The rate of fuel exergy with 5%WiDE, 5%WiDE-Al2O3-CNT, and 5%WiDE-CNT nano-additive is 3.95%, 5.98%, and 6.40% lower than pure diesel. The exergy-based sustainability for 5%WiDE-CNT fuel is highest at speed 2000 rpm and full engine load. The exergy destruction rate (EDR) and entropy generation rate (EGR) with pure diesel are 1.42% higher than 5%WiDE fuel. However, the EDR and EGR with 5%WiDE-CNT and 5%WiDE- Al2O3 -CNT nano-additive fuels are 3.14% and 4.15%, respectively, higher with respect to pure diesel. The influences of engine load, engine speed, water emulsification, and incorporation of nano-additive on the exergy-based performance characteristics are comparable with the energy-based characteristics, but the exergy characteristics are found lower than the energy characteristics. The comparative study of energy and exergy parameters for all mentioned fuels used in the DICI engine revealed that the best performance of DICI engines is found with 5%WiDE-CNT fuel.