Application of Mie-scattering theory in measurement of mean droplet diameter
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摘要: 冰风洞实验时,为了更精确地模拟实验环境,需要精确测量喷头喷出水滴的直径,为此,开发了一套激光束发射装置并基于Mie散射理论编制了水滴直径计算程序.在水滴流场的环境中,激光束发生散射,间隔Δt的时间反复实验获得多个时刻的散射光强分布图.应用自行开发的计算程序对已获得的多组散射光强分布图进行计算处理,得到同一截面不同时刻的多组水滴平均直径.利用Newton插值法对上述多组水滴平均直径进行插值,拟合出不同时刻水滴直径的连续变化曲线,对该曲线求积分平均值,获得该截面水滴的平均直径.为检验实验装置和计算程序的准确性,对某加湿器喷水系统进行实验测量,测量结果与产品说明中提供的数据吻合良好,表明该测量装置和计算程序可行.Abstract: In an ice wind tunnel experiment, in order to simulate the experimental environment more accurately, the diameter of droplets jetted from the nozzle need to be measured accurately accordingly. A set of laser device and drop diameter calculation program based on Mie-scattering theory were developed. In the environment of droplet flow field, the laser beam became scattered, experiments were repeated to obtain multiple moments of the scattering intensity distribution figures in interval of. The calculation program developed was applied to calculate the scatter intensity distribution of the figures. The mean diameters of water droplets in the same section but at different time were obtained. The Newton interpolation method was applied to interpose the data of multiple sets of the mean droplet diameters and based on the curves obtained by fitting the diameter data of the cross at different time, the average value of the integration which was considered to be the mean droplet diameter would be obtained. A humidifier was used to investigate the feasibility of the code. Good agreement between the prediction and the data provided by the product description show that the measurement device and calculation program is feasible.
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Key words:
- icing wind tunnel /
- droplet diameter /
- Mie-scattering theory /
- measurement
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