【作者】 郑中青；

【导师】 李艳红；

【作者基本信息】 上海交通大学 ， 航空宇航推进理论与工程， 2007， 硕士

【摘要】 为缓解能源结构不合理造成的环境污染问题,我国加快了天然气的使用力度,发展高效、低污染排放的天然气燃烧技术具有非常重要的现实意义。天然气在惰性多孔介质内的预混燃烧技术在很多方面体现出了其优越性,成为近年来燃烧领域的研究重点之一。本文对天然气在惰性多孔介质内的预混燃烧过程进行了数值模拟研究。在数值模拟过程中,为了保证结果的准确性,本文用分子动力学理论详细计算各组分的热物性参数和传输参数,包括比热容、粘性系数、扩散系数以及导热系数等。YIX方法是求解辐射传递方程的一种新方法,在求解非均匀介质中的辐射传递方程方面具有处理方便、准确性高等优点。本文用YIX方法对惰性多孔介质内的一维辐射传递方程进行求解。由于火焰附近的温度梯度很大,本文采用非均匀网格,用有限差分法对控制方程组进行了离散,在此基础上用Fortran语言编写了计算程序。在计算过程中,用牛顿法求解非线性方程组。由于火焰传播问题是特征值问题,本文采用固定燃烧器内某一点温度的方法求解。对数值模拟结果的分析表明,多孔介质的辐射以及气体和固体间的对流传热是影响惰性多孔介质燃烧器性能的主要因素。对流传热系数的增加会增加气体和多孔介质固体之间的热量交换,从而减小两者之间的温度差。多孔介质衰减系数的提高意味着辐射传热能力的下降,导致反应区向火焰上游和下游传递的热量减少,从而提高了反应区的温度。更多还原

【Abstract】 Natural gas is being exploited and utilized rapidly for solving the serious environmental pollution problem due to the bad energy structure in our country. To develop the technique of natural gas combustion with higher efficiency and lower pollutants emission becomes very significant. The technique of natural gas combustion in porous inert media has many advantages, and becomes an important topic in combustion research field.Premixed combustion of natural gas in inert porous media is being numerical studied. The thesis computes the thermal and transport properties of gas species with molecular kinetics theory, including specific heat volume, viscosity, diffusion coefficient and conductivity.YIX method has many advantages when solving radiation transfer equations especially in nonhomogeneous media such as easy to use and high accuracy. The thesis solves RTE in porous inert media by YIX method and uses the result to simulate the premixed combustion in porous inert media.Because of the big temperature gradient near the flame zone, non-uniform grid is used and finite difference method is used to discretize the control equations and Fortran is used to write calculating code. During the calculation process, the thesis uses Newton method to solve nonlinear equations. Because this problem is an eigenvalue problem the thesis uses the method of fixing the temperature at one point to solve it.The results show that the radiation of solid and the heat exchange between gas and solid are two main factors impacting the combustion performance of porous inert media burners. Increased convectivecoefficient between gas and solid will enhance the heat transfer between gas and solid and decrease the temperature difference between them. If the extinction coefficient of porous medium were increased, then the radiation heat transfer ability of porous medium will decrease, which will make the heat transfer from reaction zone to both downstream and upstream reduced, so the temperature of reaction zone will be higher.更多还原