Development of kinetic model reduction framework and its application in realistic flow simulation.

摘要

The main objective of this research is to develop a kinetic model reduction framework that enables incorporation of detailed chemistry with realistic flow simulation. Comprehensive computational fluid dynamics tools and detailed kinetic mechanisms have been developed, and the fully integration of these two components has been recognized as an imperative necessity to represent realistic systems. However, integrating detailed chemistry in complex flow simulation is expensive and oftentimes prohibitive. Thus this work is driven by the premise to reduce the computational intensity introduced by including detailed chemistry in realistic flow simulation and meanwhile retain acceptable accuracy. The work in this dissertation is focused on the development of an efficient yet accurate kinetic reduction method that enables dynamic reduction within the context of reactive simulations.;Excessive computational intensity introduced by the integration of detailed chemistry in reactive flow simulation stems from the large size of detailed kinetic models. The kinetic model reduction method proposed in this dissertation is to address the following two unique aspects: (i) effective reduction of model size; and (ii) efficient integration of the reduction method dynamically during reactive flow simulation without introducing significant overhead. The proposed method is based on an element flux analysis approach which provides an indicator to quantify element transitions between species. The element flux can be further implemented to retrieve useful information from the kinetic network and identify active species under given reaction conditions, which constitute the fundamental of kinetic analysis and redundancy identification in mechanism reduction. It is demonstrated in this research that element flux analysis gives rise to both an effective and efficient dynamic mechanism reduction method, as well as a useful kinetic analysis tool. The proposed approaches can be extended to multiple disciplines since a large number of applications in novel fuel development, engine design, and petro chemistry require the efficient modeling of reactive flows.