水雾热遮蔽过程的辐射与导热耦合换热

Coupled heat exchange of radiation and conduction of water sprays in the heat shielding process

人工水雾对热辐射有着强烈的散射和吸收,可用于火灾安全和红外隐身.将水雾视为吸收、发射、各向异性散射的非灰介质,考虑水雾自身辐射、多重散射和环境影响,利用Mie理论和谱带离散计算雾滴的辐射特性参数;将辐射传输方程(RTE)和能量守恒方程(ECE)耦合计算,建立红外辐射在水雾中的衰减模型.利用该模型计算了光谱半球透射率,通过与朗伯比尔定律作对比,反映了介质辐射、多重散射、辐射热流等因素会降低水雾遮蔽效率.

Artificial sprays can be used in the fire safety and infrared stealth because that they can strongly attenuate the heat radiation through the scattering and absorbing effect. A model is established to calculate infrared radiation attenuated in the spray by coupling the radiation transfer equation and energy conservation equation. Taken the sprays as an absorb- ing, emitting, anisotropic scattering non-gray medium, the medium radiation, multiple scattering of the sprays, target radiation flux, and environment are taken into account. The radiative coefficients are calculated through Mie law and nar- row bands approximation. The hemispherical spectral transmissivity is calculated with this model. By comparing with the Lambert-Beer＇s law, it was found that medium radiation, multiple scattering, and target radiation flux can weaken the spray shielding efficiency.