Investigation of dynamics of hydrogen-rich flames, development of new methods for validation of mechanisms of chemical kinetics and for model reduction

目前，无论是利用烃类燃料燃烧的实用装置的开发，还是燃烧和爆轰物理领域的理论研究，都是基于烃类燃料氧化反应详细动力学的数学模型的数值处理。目前已有许多专门描述烃氧化高温燃烧过程的动力学机制。这可能包括成百上千的基本步骤，它们有自己的反应常数。然而，这些反应常数的直接和间接实验测量是非常有限的。因此，建立一个准确可靠的燃烧波传播的数学模型仍然是一项非常具有挑战性的任务，任何额外的化学反应机制的验证和验证方法对于燃烧过程的建模都是非常宝贵的。在拟议的项目中，作者建议开发一种方法来验证和验证氢燃烧机制。这是因为由于储能技术的应用，氢燃烧仍然是一个热门话题，因此同时减少了二氧化碳的排放。特别重要的是发展安全问题的数学燃烧模型，其中需要可靠的机制来描述瞬态状态，非稳态状态典型的爆炸过程。此外，氢氧化是所有已知的轻烃和重烃氧化详细机制的核心子机制。与此同时，由于燃烧过程在技术几何和流动条件下的高维数和特征时间尺度和长度尺度上存在较大差异，仍然超出了实际应用范围。控制方程系统的维数和刚度极大地复杂化了数值处理，并导致了非常高的CPU和内存存储要求。因此，简化动力学机制的发展提出了本研究的另一个关键问题。所建议的方法将基于对复杂燃烧系统和反应系统状态空间中发展的低维慢不变流形中出现的非线性波形的动力学特性的研究。该项目的成功实现将为化学动力学机制的验证开辟新的视角，显著推进燃烧理论和应用，包括工业用途。动力学机制的自动还原方法将在复杂几何和流动条件下烃类燃烧过程控制和优化的数值计算中发挥关键作用。

Nowadays, not only the development of practical devices, which utilize combustion of hydrocarbon fuels, but also theoretical research in the field of physics of combustion and detonation are based on the numerical treatment of mathematical models using detailed kinetics of oxidation reactions of hydrocarbon fuels. At present there is a number of kinetic mechanisms developed specifically to describe the high temperature combustion processes of hydrocarbon oxidation. These may include hundreds and thousands of elementary steps with their own reaction constants.However, direct and indirect experimental measurements of these reaction constants are very limited. Thus, development of an accurate and reliable mathematical model of combustion wave propagation still represents a very challenging task and any additional method of verification and validation of chemical reaction mechanisms is invaluable for modelling of combustion processes.In the proposed project, the authors suggest to develop a method for validation and verification of the hydrogen combustion mechanisms. This is because hydrogen combustion remains a hot topic due to applications for energy storage technologies and, therefore, simultaneously reduction of CO2 emissions. Particularly important is the development of mathematical combustion models for safety issues, where reliable mechanisms describing the transient regimes, non-stationary regimes typical for explosion-like processes, are required. Moreover, hydrogen oxidation represents the kernel sub-mechanism for all known detailed mechanisms of light and heavy hydrocarbon oxidation.At the same time numerical treatment of combustion processes in technical geometries and flow conditions are still beyond practical applications due to high dimensionality and the presence of large differences in the characteristic time and length scales. Dimensionality and stiffness of the system of governing equations complicates numerical treatment enormously and leads to very high CPU and memory storage requirements. Thus, the development of reduced kinetic mechanisms presents another key problem of the proposed study.The suggested methodology will be based on the investigation of the dynamical characteristics of nonlinear wave patterns, which emerge in complex combustion systems and on low-dimensional slow invariant manifolds developed in the reacting system state space. The successful realization of the project will open new perspectives in verification of mechanisms of chemical kinetics, significantly advance combustion theory and applications including industrial uses. The methods for automatic reduction of kinetic mechanisms will play a pivotal role in numerical computations for control and optimization of combustion processes of hydrocarbons in complex geometries and flow conditions.