Combustion Chemistry and Parameter Estimation
Combustion processes in practical systems are marked by an huge complexity stemming from their multi-dimensional character, from the interaction of physical processes (including diffusion, flow dynamics, thermodynamics and heat transfer), and from the ext
- PDF / 300,125 Bytes
- 20 Pages / 439.36 x 666.15 pts Page_size
- 100 Downloads / 217 Views
Abstract Combustion processes in practical systems are marked by an huge complexity stemming from their multi-dimensional character, from the interaction of physical processes (including diffusion, flow dynamics, thermodynamics and heat transfer), and from the extremely complex chemistry potentially involving up to hundreds of species and thousands of elementary reactions. The determination of accurate parameters accounting for the chemical kinetics is an essential step for predicting the behavior of practical combustion systems. This is usually done by carrying out specific experiments in simplified systems whereby many of the physical phenomenons mentioned above can be neglected. The present paper aims at giving an overview over the approaches currently followed to estimate kinetic parameters based on experimental data originating from these simplified systems. The nature and mathematical description of such problems are presented for homogeneous systems where all variables depend on time only. The techniques for the identification of the most significant reactions (and hence parameters) are shown along with methods for mechanism reduction considerably alleviating the computational burden. As an application example, Mechacut, a CCC procedure written by the authors is employed for the reduction of a detailed reaction mechanism aiming at describing the combustion of methane CH4 . In the following section, the estimation of kinetic parameters is formulated as an optimization problem and different approaches found in the current literature are examined.
M. Fischer () Interdisciplinary Center for Scientific Computing (IWR), University of Heidelberg, Germany e-mail: marc.fischer [email protected] U. Riedel Institute of Combustion Technology, German Aerospace Center (DLR), Stuttgart, Germany e-mail: [email protected] H.G. Bock et al. (eds.), Model Based Parameter Estimation, Contributions in Mathematical and Computational Sciences 4, DOI 10.1007/978-3-642-30367-8 10, © Springer-Verlag Berlin Heidelberg 2013
207
208
M. Fischer and U. Riedel
1 Introduction Realistic simulations of combustion processes in the twenty-first century have become primordial in view of the numerous challenges and problems that have emerged during the past decades: global warming which requires more efficient ways to convert energy while limiting the emissions of gas fostering the green house effect, health concerns with regard to harmful pollutants (including nitric oxides (NOx), photochemical pollutants inducing the formation of smog and particulate matters having hazardous health effects) coupled with the growing influence of emerging countries like China which increasingly exploits its fossil coal resources. The intense research activities aiming at producing sustainable renewable fuels show also that the importance of combustion is not going to be diminished by the disappearance of traditional fossil fuels like oil. For all these reasons, an important research effort has to be done in order to reach an accurate estimation of parameters acc
Data Loading...
