高超声速飞行器红外窗口热辐射特性试验

对于大气层内的高速飞行器,强烈的气动加热使红外探测系统的红外窗口温度迅速上升,成为气动热辐射效应的主要因素,导致红外探测系统的探测距离、识别概率、跟踪精度等性能下降,甚至失效。通过简化红外窗口热辐射传输模型,设计了一种红外窗口热辐射特性试验平台,并对某蓝宝石红外窗口在中波红外3.7~4.8 m波段的热辐射特性进行试验研究。研究结果表明,在100~350 ℃高温范围内,该红外窗口热辐射特性与温度近似呈现3次方关系,随温度升高,透过率下降约16%,而自身辐射持续增强,幅度最高在100倍以上,对红外探测系统造成的影响比透过率要大得多。

Experiment of the thermo-radiation characteristic of infrared window of hypersonic vehicles

When hypersonic vehicles have flights in atmosphere, the temperature of the window of infrared (IR) detection systems rise rapidly, due to the aerodynamic heating by hypersonic airflow around. High-temperature IR windows dominate the aero-thermo-radiation effect, which reduce the performance of IR detection systems, including detection range, identification probability, tracking precision, and so on, or even make these systems fail. By simplifying radiation transfer model for IR windows, an experiment platform was designed to measure thermal-radiation characteristics of IR windows. On the platform, the experiment on thermal-radiation characteristics of a sapphire window were studied, in 3.7-4.8 m. The research result indicates that, in 100-350 ℃, the higher the temperature of the sapphire IR window is, the smaller the transmittance is, and the stronger the self-radiation is. Both the transmittance and the self-radiation are related to the third power of the window temperature. From 100 ℃ to 350 ℃, the transmittance of the window drops about 16%, otherwise the self-radiation enhances above 100 times, of which the influence on the MWIR detection system is bigger than that of transmittance.