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为了降低直升机发动机舱蒙皮的温度,减弱直升机红外辐射能量,采用数值仿真的方法研究其处于悬停状态、考虑了旋翼下洗作用的发动机舱蒙皮温度场和直升机红外辐射特性.针对基准发动机舱结构提出了在舱内加设辐射遮挡套、增开通风百叶窗、排气管尾缘修型和蒙皮内侧敷设隔热层等改进方案,研究了上述改进方案对直升机发动机舱蒙皮温度场和红外辐射特性的影响,得到了如下结论:①在发动机舱内加设辐射遮挡套后,整机侧向探测方位角内3~5μm红外辐射强度出现了约25%的增幅,8~14μm波段红外辐射与原始结构相当.②在发动机舱顶部增开通风百叶窗,直升机3~5μm红外辐射低于原始结构约12%,8~14μm波段红外辐射与原始结构相当.③在发动机舱顶部增开通风百叶窗的基础上,对排气管尾缘采取延伸遮挡以及在发动机舱蒙皮内侧敷设隔热层,整机3~5μm波段红外辐射的最大值下降约70%,8~14μm波段红外辐射的最大值下降约10%.
In order to reduce the temperature of the helicopter engine compartment skin and weaken the infrared radiation energy of the helicopter, numerical simulation is used to study the hovering state of the helicopter cabin skin temperature field and the infrared radiation characteristics of the helicopter. The cabin structure is proposed to improve the temperature field of the helicopter’s engine compartment by setting up a radiation shielding cover, increasing the ventilation louver, tailing the exhaust pipe and laying the insulation layer on the inner side of the cabin. And the infrared radiation characteristics, the following conclusions are obtained: (1) After the radiation shelter is installed in the engine compartment, the infrared radiation intensity of 3 ~ 5μm in the lateral detection azimuth of the whole machine shows an increase of about 25% The infrared radiation is equivalent to the original structure.②The ventilation louver is added on the top of the engine compartment, the infrared radiation of 3 ~ 5μm helicopters is lower than the original structure by about 12%, and the infrared radiation in the 8 ~ 14μm band is equivalent to the original structure.③In the top of the engine compartment, Blinds on the basis of the exhaust pipe tail edge to take an extended shelter and inside the engine compartment skin laying insulation layer, the whole 3 ~ 5μm band infrared radiation About 70% of the maximum value, and the maximum value of the infrared radiation in the 8-14 μm band is reduced by about 10%.