人造水雾粒度测试及红外消光因子计算分析

在大型半密闭空间内发生具有不同粒度分布的水雾体系,用喷雾激光粒度仪测试粒度分布规律并采用Van Der Hulst公式计算不同大小水雾粒子对红外辐射的散射效率因子、吸收效率因子和消光效率因子。结果表明:试验条件下水雾粒子的平均直径在5~65μm范围内。计算结果显示:水雾粒子对3～5、8～14μm红外辐射的消光作用主要取决于散射效应而非吸收效应。当水雾粒子的直径大于等于红外辐射的波长时,水雾体系对该波长红外辐射能够产生较强的消光效果。综合分析水雾体系的稳定性和消光特性,直径在3~30μm之间的水雾粒子对3～5、8～14μm红外辐射的衰减效果更为明显。

Testing of Granularity of Artificial Water Fog Particles and Calculation for Infrared Extinction Factors

The superfine water fog was generated in a large half-closed space under different conditions and the granularity of the particles was tested with a spray laser particle size analyzer.The scattering,absorption and extinction efficiency factors of water fog particles with different diameters to infrared emission were calculated according to Van Der Hulst formula based on Mie scattering theory.The experimental results showed that the average diameter was varied from 0.5 μm to 65 μm under the experimental conditions.By the calculation,the attenuation effect of water fog particles on infrared emission depended on not absorption but scattering function.According to the extinction curves,the water fog particles produced good extinction function to infrared emission when the particle's diameter was not smaller than the wavelength of the incident infrared emission.As a conclusion,the water fog particles had good attenuation effect to 3~5 μm and 8~14 μm infrared emission when its average diameter was in range of 3~30 μm.