Validação de mecanismos cinéticos químicos reduzidos para mistura de gasolina-etanol em um motor de combustão interna

Abstract

The demands and regimentation on fuel consumption, efficiency and especially on vehicle emissions have been becoming increasingly stringent, reinforcing the need to optimize internal combustion engines. Aiming a better understanding of the combustion process, this work investigates, through numerical simulation, the behavior of two reduced chemical kinetic mechanisms of the gasoline-ethanol blends in a singlecylinder engine with direct injection and homogenous charge. These two mechanisms have, respectively, 75 species and 343 reactions; 115 species and 639 reactions. They are evaluated in relation to the size of the kinetic chemical mechanism, the reproduction of the combustion phenomenon and the computational feasibility of the numerical simulation. The methodology is based on the reproduction of results of experimental tests for the validation of three-dimensional simulations using the Converge CFD software for the evaluation of chemical kinetic mechanisms. For the three-dimensional model were used boundary conditions obtained from experimental tests and also from one-dimensional numerical simulations by GT-Power software. The results are divided in two main parts. In the first part, the behavior of these two reduced mechanisms is compared with a chemical kinetic mechanism from the literature and with the experimental data for the E10 in the rotation of 3000 rpm and load of 6 BMEP. The mechanism of 75 species and 343 reactions presents the best results for the reproduction of the combustion. In the second part, the behavior of the engine 75 species and 343 reactions is evaluated, and its performance is analyzed for the reproduction of gasolineethanol blends in different concentrations (E27, E50, E85, E100) in the same rotation and load conditions (3000 rpm and 6 BMEP)