Ethanol is one of the most widely used biofuel in the field of combustion. Uses of this fuel as an additive with gasoline makes it more vital component for combustion research. Details studies of fuel includes numerical calculation which required chemical mechanisms. A generation of skeleton mechanism from a detail chemical kinetic is necessary in the prospect of numerical computation.  In this work a skeleton reduction is done on a detail kinetic mechanism of ethanol. The skeleton mechanism is generated using directed relation graph technique with error propagation and sensitivity analysis (DRGEPSA). The detailed ethanol mechanism used here is developed through reaction mechanism generator (RMG). The generated mechanism is validated at wide range of engine relevant operating conditions using laminar burning speed (LBS), ignition delay time and species mole fraction calculation at different reactor conditions. This detail mechanism consists of 67 species and 1031 reactions. Though the mechanism is in a very good agreement at various operating ranges with experimental data, it is costly to use a detail mechanism for 3D computational fluid dynamics (CFD) analysis. To make the mechanism applicable for CFD simulation further reduction of species and reactions is essential. The skeleton mechanism generation technique used in this present study (DRGEPSA), works based on error calculation at user defined condition. This technique is a combination of two methods, directed relation graph with error propagation (DRGEP) and directed relation graph with sensitivity analysis (DRGASA). The error calculation for reduction process is done based on ignition delay calculation at constant volume reactor condition. To ensure the wide range of applicability for the skeleton mechanism the ignition delay is calculated at temperature, pressure and equivalence ration ranges from 700-2000 K, 1-40 atm and 0.4-1.4 respectively. An error estimation from 10-20 % is considered during the process. Initially DRGEP is applied on the detail mechanism to eliminate unimportant species from the mechanism. Further, sensitivity analysis helps to identify and reduce more unimportant species for the final skeleton mechanism. Reactions related to the deleted species are automatically removed from the mechanism in each step. The final skeleton mechanism has 45 species and 450 reactions. This skeleton mechanism is validated and compared initially with different ignition delay data for the conditions not used in reduction technique. LBS results of experiment and detail mechanism is used to further validate the mechanism. Species concentration calculation using jet stirred reactor is also considered for validation. For future work this skeleton mechanism will be considered in optimum reduction process.


Ethanol Mechanism Reduction Based on DRGEPSA Method at Various Operating Ranges

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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