【作者】 王健；

【导师】 张爱红；

【作者基本信息】 哈尔滨工业大学 ， 光学工程， 2010， 硕士

【摘要】 随着现代新军事技术变革到来,采用红外成像的探测跟踪制导,已经成为了当代各种高速精确制导飞行器必然发展趋势。当带有光学成像探测系统的飞行器在大气层中高速飞行时,它的光学头罩和大气之间发生剧烈的相互作用,进而产生了严重的气动光学效应。其中高温光学窗口和激波气体气动热辐射效应对成像器形成了辐射干扰,使红外图像噪声增加,导致光学成像探测系统成像质量下降,制导精度也因此而降低。本文主要研究气动热环境下光学头罩热辐射效应。对头罩内的辐射传输进行建模仿真,利用得到的边界辐射热流,分析光学系统内的辐射传输过程,最终给出探测器上的辐射能量分布。气动热环境下头罩内热辐射传输是辐射和导热耦合换热的过程。通过对头罩进行空间和角度的划分,给出了辐射传递方程和导热能量方程的离散形式。采用直角坐标系下的有限体积法求解头罩内的辐射传输,并把头罩内部辐射热流作为辐射热源项代入导热能量方程,求解头罩的辐射温度场,反复进行辐射和导热的迭代,直至辐射温度场收敛,最后给出头罩内表面的辐射热流。采用反向蒙特卡洛法对光学系统内辐射传输进行建模。追迹红外探测器上每个像元上发射出的大量光线,模拟光线与每个光学元件的相互作用,统计到达头罩内表面每个微元面上的光线比例,并在Visual C++环境下编制相应的光线追迹程序,计算出辐射传递因子。根据辐射传递因子的互易性,计算出红外探测器上的辐射能量分布。论文中通过对仿真结果的分析,证明了头罩内部的辐射传输建模和光学系统内辐射传输建模是可行的。更多还原

【Abstract】 With the advent of a new era of military technology revolution in modern times, it is necessary and inevitable to equip high-speed precise guided aero crafts with infrared imaging detecting and tracking guidance technique. As high-speed aero crafts with optical imaging detecting system fly in the atmosphere, severe aero-optical effect is incurred by the intense interaction between its optical dome and the atmosphere. During the process, the radiation effect of optical dome and shock wave influence the imaging system severely. So the image quality of the aero-crafts optical imaging detecting system is impaired and thus the guidance precision will decrease.Aimed at studying optical dome radiation effect under the circumstances of aerodynamic heat, this paper showed the distribution of radiant energy on the infrared detector. The final result was based on the modeling and stimulation of the radiative transfer in the dome and the analysis of the radiative transfer process in the optical system by obtaining the marginal heat flux.The model of radiative heat transfer in optical dome was established on the process of coupled radiative and conductive heat transfer. Radiative transfer equation and conductive energy equation were formulated according to the division of space and angel of the dome. And the radiative transfer in the dome was calculated by means of finite volume method under the rectangular coordinate system. Meanwhile, the radiative temperature field of the dome was obtained by introducing the radiative heat flux as radiative heat source into the conductive energy equation. The iteration into radiative and conductive equation till the convergences of the radiative temperature field, finally solved radiative heat flux inside the dome.Backward Monte Carlo Method was applied to model the radiation transmission in optical system by tracing scales of rays and simulating interaction between rays and optical elements. At the same time the ray-tracing programs were also programmed in Visual C++ 6.0, which gave the radiative exchange factor and radiative energy distributions on infrared detector.The analysis of the stimulation result in this paper indicates that the model of radiative heat transfer in the dome and the optical system is feasible.更多还原