Exergy analysis under consideration of operational parameters by numerical approach in a two-stroke marine diesel engine.

• A numerical model of a two-stroke marine diesel engine was developed and validated. • The effects of start of injection and scavenge air inlet temperature on exergy terms were investigated. • The exergy efficiency decreases from 43.45% to 41.36% as start of injection delays. • The exergy efficiency reduces from 42.83% to 41.44% as scavenge air inlet temperature increases. • The optimal strategies for minimizing exergy destruction and maximizing exergy. This paper presents a numerical approach of the influence of operational parameters on the exergy terms in a two-stroke marine diesel engine. Operational parameters are introduced as different start of injection (-4, -2, 0 and 2 °CA) and scavenge air inlet temperature (300, 312, 330 and 340 K) values. The energy analysis is conducted within a closed cycle by using a three-dimensional computational fluid dynamics code. The simulation results are compared with the corresponding experimental pressure data in the literature and show good agreement. Also, the exergy analysis is performed by a developed in-house computational code. Various exergy rates and cumulative exergies are detected and computed separately at operational parameters. The study reveals that varying the start of injection timing from −4 to 2 °CA at full load condition results in a decrease in exergy efficiency from 43.45 % to 41.36 %. Furthermore, an increase in scavenge air inlet temperature from 300 K to 340 K leads to a reduction in exergy efficiency from 42.83 % to 41.44 %. These findings underscore the critical influence of injection timing and scavenge air temperature on the exergy performance. In light of these results, this paper gains more insight into the impact of design parameters of a two-stroke marine diesel engine on exergy efficiency and presents a preliminary data for marine diesel engine manufacturers in the design of a two-stroke marine diesel engine that uses energy efficiently. [ABSTRACT FROM AUTHOR]