Keywords: energy analysis, exergy analysis, 3D modelling, exergy efficiency, combustion irreversibility, multidimensional modelling, engine load, indirect injection, IDI diesel engines, CFD, computational fluid dynamics, second law thermodynamics
Multidimensional modelling of the effect of engine load on various exergy terms in an indirect injection diesel engine
In this investigation, the energy and exergy analyses are carried out in a Lister 8.1 IDI diesel engine for different loads (25%, 50%, 75% and full loads operation) at maximum torque engine speed (730 rpm). The energy analysis is done during a closed cycle using of a three dimensional CFD code. The results by this model for the pressure in cylinder at 50% and full load operations are compared with the corresponding experimental data and show good agreements. Second–law analysis is carried out by a developed in house computational code. Various rate and accumulative exergy components are identified and calculated separately with crank position for various loads. The results show that when the load increases from 25% to full load in steps by 25%, the percentage of combustion irreversibility decreases from 33.7% to 25% of fuel burn exergy. Also, exergy efficiency reaches its peak of 36.7% at 75% load.