Reduction of large kinetic mechanism of N-heptane using directed relation graph and computational singular pertubation methods

Abstract

Increasing demand on energy makes scientists and engineers enthusiastic to nd new and e cient ways while designing new engines. For this purpose, a tremendous e ort is paid on fossil fuels which have an important role in energy eld. Simulating fuels in computers is one of the most signi cant and useful methods in design and calculations thanks to it's cheapness and time e ciency. One of the most important points in here is that the reliability of the data used in the simulations. In this context, simulating fuels by using detailed mechanism taking both the all species and reactions occured during combustion into account is needed. However, working with the detailed system is only waste of time related to their level of detail. In this thesis, reduction of detailed mechanism of one of the most acknowledged diesel surrogate fuel called as n-heptane including 654 species and 4846 reversible reactions, is made. In this context, rstly the Directed Relation Graph Method has been applied for the adiabatic ignition results of n-heptane for wide range of conditions in terms of temperature, pressure, and stochiometry. In the end, skeletal mechanism that include 135 species and 1309 reactions is obtained. In addition, with the aim of eliminating the stifness, time scale analysis is utilized via using computational singular perturbation method. By this way, it is possible to eliminate stifness causing extra CPU times. Finally, the accuracy of the results have been evaluated by showing di erent ignition models.