Advanced Exergy Analysis of Air-Film Blade Cooled Marine Gas Turbine (LM2500+) 2018-01-1372
Exergy analysis provides appropriate information for improvement of thermodynamic efficiency of the system focusing on system components with maximum exergy destruction. But this method lacks in showing the mutual interaction between system components on cycle performance. Hence an advanced approach i.e. Advanced Exergy Analysis’ has been adopted and discussed in present paper. Advanced exergy analysis of LM2500+, a marine gas turbine cycle adopting air-film blade cooling techniques has been reported. The advanced exergy analysis primarily focuses on categorizing the irreversibility of process components. Advanced exergy analysis identifies exergy destruction based on two different aspects: first identifying source of irreversibility and other being minimization of this irreversibility. Thus, advanced exergy analysis splits exergy destruction into endogenous and exogenous exergy destruction as well as avoidable and unavoidable exergy destructions. Advanced exergy analysis also reveals real improvement potentials depending on operating conditions. Endogenous exergy destruction is the result of the irreversibility of a component being analyzed exclusively, whereas exogenous part of exergy destruction is a result of inefficiencies of the remaining components of the cycle. The unavoidable exergy destruction shows the part of exergy destruction of an individual component which may not be achievable in near future even after significant technological development. The analysis also highlights some key factors focusing on which might help marine gas turbine manufacturers to minimize cycle irreversibility. The result shows that endogenous exergy destruction within marine gas turbine cycle components has been reported to be ≈ 81% which shows weak interactions among system components. Also exergy efficiency of the system in real cycle condition has been observed as ≈ 37.4%. The unavoidable exergy destruction of the analyzed system has been found to be ≈ 91.2% showing lesser improvement potential for thermodynamic system.