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建立了带有波瓣混合器、加力燃烧室及中心锥的涡扇发动排气系统流场计算模型和3~5μm波段红外辐射特性仿真模型,并通过发动机地面辐射特性测试对计算模型进行验证。对降低壁面发射率、部件冷却及两种方案结合三种红外辐射抑制方案开展研究。结果表明:降低壁面发射率能抑制除90°外所有方向的红外辐射;在0°时,发射率每降低0.15,全部涂覆的抑制效果提高约16%;局部涂覆的抑制效果提高约14%;中心锥温度降低300 K,0°~15°的辐射抑制幅度达44%;喷管扩散段温度每降低25K,在50°方向能产生8%的抑制效果;当两种方案结合时,在0°~5°能够产生80%的抑制效果。在10°~40°产生50%的抑制效果。随着探测角进一步增大,固体辐射所占比例下降,抑制效果降低。
A flow field calculation model of the turbofan engine exhaust system with a lobe mixer, an afterburner and a center cone was established, and a simulation model of the infrared radiation characteristics in the band of 3~5 μm was established. The calculation model was verified by testing the radiated characteristics of the engine surface . To reduce the wall emissivity, component cooling and two programs combined with three kinds of infrared radiation suppression program to carry out research. The results show that reducing the wall emissivity can suppress infrared radiation in all directions except for 90 °. At 0 °, the emissivity reduces by 0.15 for each coating, and the total coating effect is improved by about 16%. The effect of local coating is increased by about 14 %; Center cone temperature decreased 300 K, radiation inhibition range of 0 ° ~ 15 ° 44%; nozzle diffusion section temperature decreases 25K, 50% direction can produce 8% inhibition; when the two programs combined, At 0 ° ~ 5 ° can produce 80% inhibition. At 10 ° ~ 40 ° produce a 50% inhibitory effect. With the further increase of the detection angle, the proportion of solid radiation decreases and the suppression effect decreases.