外形包络面的尾焰红外图像仿真

基于粒子系统的尾焰红外图像仿真计算量大，难以与红外辐射的计算模型相结合。为了解决这个问题，首先提出了基于化学反应式的航空发动机尾焰气体组分计算模型，改进现有的尾焰流场工程计算方法；然后提出了基于外形包络面的尾焰红外图像仿真模型，研究了包络面的建立、包络面模型与流场计算模型以及气体辐射计算模型的结合、包络面模型对尾焰红外图像影响三个相关问题；最后通过数值仿真得到了尾焰的红外图像。结果表明:尾焰的红外图像主要由其核心区的高温气体决定；当包络范围增大到一定程度后，尾焰图像与选用的包络面的外形无关；选择一个易于划分面元的包络面模型，并划定能全面反映尾焰辐射分布特征的小包络面范围，可使尾焰图像的生成更加高效准确。

Simulation of plume IR image based on figure envelope

The plume IR image simulation based on the particle system needed large computation and was difficult to be integrated with the IR calculation model. To solve the problem, firstly based on the chemical reaction formula, the gas fraction calculation model of the aero engine's plume was established, and the engineering plume flow field calculation method was improved. Then based on the figure envelope model, the simulation model of the plume IR image was established. And three relative problems were studied: how to establish the figure envelope, how to combine the figure envelope model with the flow field calculation model and gas IR lightness calculation model, and the relation between the figure envelope and plume IR image. Finally, the plume IR image was generated by numerical simulation. The results show that the plume IR image is defined by the high temperature gas of the core area;the plume IR image is unrelatable with the figure envelope when the envelope is enlarged to a certain extent;the plume IR image is generated more effective and accurate when the figure envelope is easy to be divided into meshes, is small but can reflect the plume radiation distribution characters.