Abstract: To reduce the infrared radiation of an axisymmetric exhaust system of turbofan engine, the infrared suppression laws by reducing exhaust system surface temperature and emissivity were investigated. Firstly, the infrared suppression effects of cooling and low emissivity coating on the cone surface were investigated by simulative experiment. Secondly, the computer code adopted in current research was validated with the experimental results. Lastly, the effect laws of reducing temperature and emissivity distribution on the infrared radiation(IR) characteristics of turbofan engine exhaust system with typical size were computed by the validated code. The results show that the IR intensity within the region of α<15° could be clearly suppressed by reducing temperature and emissivity of cone and other components. If the temperature of cone decreases by 100K, and the surface emissivity of cone, blade and radial flame holder reduce to 0.2. The IR intensity can decrease by more than 40%, and the detection range can be reduced by about 20%.

Key words: Turbofan engine； Exhaust system； Infrared stealth technology; Cooling； Low emissivity； Detection range

摘要： 为了降低涡扇发动机轴对称排气系统的红外辐射特征,研究了降低排气系统腔体表面温度和发射率抑制红外辐射的规律。首先通过模拟实验研究了对中心锥进行冷却和涂覆低发射率涂层的红外抑制效果；然后用实验数据对本文使用的红外辐射特征计算方法和程序进行了验证；最后通过数值计算研究了典型尺寸的涡扇发动机排气系统降温和发射率分布对红外辐射特征的影响规律。结果表明:降低中心锥等部件的温度和发射率可明显降低排气系统在α<15°范围内的红外辐射强度；若中心锥的温度降低100K,中心锥、涡轮和径向稳定器等部件的表面发射率降至0.2,则排气系统尾向的红外辐射强度可降低40%以上,探测距离缩短20%左右。

关键词: 涡轮风扇发动机;排气系统;红外隐身技术;冷却;低发射率;探测距离