正十烷简化机理的构建及其在发动机燃烧数值模拟中的应用

为了预测发动机点火包线和贫/富油极限等关键性能,迫切需要发展航空燃料及其典型组分的高精度化学动力学模型.针对燃料典型组分正十烷,采用自主开发的机理生成程序ReaxGen构建了其燃烧详细机理(1499种组分、5713步反应).为了验证机理的合理性与可靠性,在当量比Φ=0.5～2.0,压力p=0.1～8MPa的宽工况条件下...

Reduced Mechanism for n-Decane Combustion and Its Application in Numerical Simulation of Aeroengine Combustor

The energy release and combustion characteristics of fuel in aeroengines play an important role in the design of engines. In order to predict key performances such as engine ignition envelope and lean/rich fuel limit, there is an urgent need to develop high-precision chemical kinetic models of aviation fuel and its typical components. In this work, focusing on the typical component surrogate of n-decane in aviation fuel, a detailed mechanism for n-decane combustion including 1499 species and 5713 reactions is developed based on the automatic mechanism generation program of ReaxGen. In order to verify the reliability of the mechanism, the ignition delay simulation is carried out under the equivalence ratio of 0.5-2.0 and pressure of 1-80 atm. The results show that the detailed mechanism of n-decane has a good performance under a wide range of temperature, pressure and equivalence ratio. In order to obtain a high-precision simplified mechanism for aeroengine combustion simulation, the semi-detailed mechanism containing 709 species and 2793 reactions is generated through the method of directed relation graph with error propagation. Further, in the high temperature range of 1000-1500 K, the skeletal mechanism of 77 species and 359 reactions is developed by the paths flux analysis method. The skeletal mechanism reasonably describes the combustion characteristics of n-decane at high temperature, and the scale of the skeletal mechanism is suitable for the numerical simulation of combustion based on the flamelet generated manifold method. Based on the high precision skeletal mechanism, combining with the turbulent combustion model of flamelet generated manifold, the large eddy simulation method is used to simulate the single-head fan of the annular aeroengine combustor, and the unsteady flow field is preliminarily obtained. The results of temperature simulation are consistent with the experimental values.