基于Fluent的飞行器流场建模与红外辐射特性分析

以某型战斗机为研究对象，通过三维建模与网格划分过程建立飞机的流场计算模型，基于商用CFD软件ANSYS Fluent 16.0对飞机的外流场特性进行数值模拟。计算中利用太阳射线追踪算法综合考虑了太阳辐射对机身温度场的影响，采用离散坐标法（DO辐射模型）对辐射传输方程进行耦合迭代计算，利用不带化学反应的组分输运模型（Species Transport Model）模拟燃烧后高温尾焰喷射过程，获得了飞机外流场的温度、浓度及尾流组分分布数据。简要分析了太阳辐射对温度场变化的影响，飞行马赫数对流场红外辐射的影响以及尾焰流场分布情况。分析表明:太阳辐射对蒙皮加热较小，最高升温效果仅为5 K左右，随马赫数的增加飞行器机身背部与腹部红外辐射强度差异明显，最高时腹部辐射强度为机身最大辐射强度2倍左右，激波作用下尾焰后方会出现最高450 K和580 K两个间断的核心高温区域，尾焰红外辐射强度分布符合梨形特征分布趋势。

Modeling of flow field and analysis of IR characteristic of aircraft based on Fluent

Taking a fighter aircraft as the research object, the flow field calculation model of the aircraft was established by the three-dimensional modeling and meshing process, and the numerical simulation of the flow field characteristics of the aircraft was carried out based on the commercial CFD software ANSYS Fluent 16. The effect of solar radiation on the temperature field of the fuselage was considered by using the solar ray tracing algorithm, the discrete ordinates method for DO radiation model was used to calculate the iterative calculation of the radiation transfer equation, simulating the after-combusting tail flame injection process with component transport model without chemical reaction (Species Transport Model), and the temperature, concentration and component distribution data of the outflow field of the aircraft were obtained. The influence of solar radiation on the whole temperature field distribution, the influence of the Mach number on the infrared radiation of the flow field and the distribution of tail flame flow field were simulated and analyzed. Analysis shows that the effect of solar radiation on heating of the skin is only about 5 K. With the increase of the number of Mach aircraft fuselage and the difference of infrared radiation intensity is highest in the abdomen, abdominal radiation intensity is about 2 times the maximum radiation intensity. Under the shock wave, there will be the core high temperature region with the highest two 450 K and 580 K discontinuity at the rear of the tail flame. The infrared radiation intensity distribution of the plume conforms to the pear shape distribution trend.