Numerical Simulation Of Interactions BetweenTurbulence And Complex Chemistry To The Dissipative Scale

The real fire is turbulent combustion process. The turbulence interacts with complex chemistry on multi-scale space. The research about interactions between turbulence and complex chemistry is a task of great importance and challenge. The spatial scales of turbulence can be divided into energetic scale, inertial sub-range scale and dissipation scale. The strong interaction between the turbulence and complex chemistry starts from the smallest scale of the turbulence, the dissipation scale.There are two important issues to deal with to discuss the interactions between turbulence and complex chemistry:the high accuracy simulation of turbulent flame coupled with detailed chemical reaction mechanism and the challenge of systematically and comprehensively extracting salient information from the massive output using rigorous computational utilities. In this paper, one-dimensional turbulence model and chemical explosive mode analysis, CEMA, were used to solve these two problems. The new computation platform built in this paper is useful to discuss the interactions between turbulence and complex chemistry. Simulations of the typical hydrogen jet flame and the effect of extinguishing agent is made to introduce the validation of the new computation platform.The analysis and reduction of the detailed reaction mechanism is very important for the rigorous turbulence combustion simulation. The robustness and usefulness of the two mechanism reduction methods, direct relation graph method and directed relation graph with error propagation method, was analyzed in this paper. A new concept of "strong ties species group" was introduced in this paper. The analysis of the numbers of the strong ties species group clearly showed the aggregation behavior of the species in the detailed mechanism. In this paper, the research about the parallel computing for detailed mechanism with the Graphics Processing Unit (GPU) was also introduced.One dimensional turbulence model, or ODT for short, can achieve dissipation scale turbulence simulation coupled with detailed chemical mechanism. In this paper, the computing framework, turbulence mechanism and numerical solution method of the ODT model were introduced.Scientific method is needed to process the huge datasets that was produced by the turbulence simulation with detailed chemical kinetic mechanisms. The chemical explosive mode analysis (CEMA) is a systematical method to detect ignition, extinction, premixed flame fronts and the control species and reactions in the flame. The math theory and application methods coupled with ODT model was illustrated in this paper.The CEMA of auto-ignition and ODT simulations with fire extinguishment agent showed that the CEMA is a useful method to identify the change point of auto-ignition and extinction. The results showed that the agents can significantly delay the ignition time and reduce the chemical explosive mode. The fire extinguishment agent can lower the Da number of the local system. When the Da number is lower than1.0, the flame will extinguish.The CEMA of the hydrogen jet flame clearly showed the major control variables and reactions in different acting areas.The main contribution and innovation can be summarized as follows:a new numerical analysis platform named ODT+CEMA was built to analyze the interactions between turbulence and complex chemistry.