线光源平板降膜光催化反应器表面光辐照度分布的研究

摘要

采用简化的线性光源球面辐射模型,导出了线光源平板降膜光催化反应器液膜表面光辐照度和辐射能通量的计算公式.对表面光辐照度和辐射能通量进行了无因次化理论分析,在反应器面积一定的情况下,计算了不同线光源长度、灯距和反应器长宽比等因素影响下液膜表面的光辐照度分布和光利用率.结果表明:在线光源和平板反应器的诸参变量中,灯距是最敏感的参变量,逐步增大灯距可使光辐照度分布趋于均匀,但光利用率却随之迅速下降,因此需权衡利弊确定合适灯距.比较了实验条件下反应器中部和边缘液膜表面紫外线灯管照射下的光辐照度测量值和光辐照度理论计算值,二者基本相符.%A simplified linear source spherical emission radiation model was developed to derive formulae which are used to evaluate the light irradiance and the radiation flux on the liquid film surface of a falling film photocatalytic flat plate reactor under different operation conditions.Non-dimensional analysis of theoretical light irradiance and radiation flux was done by using the formulae. The irradiance distributions and light utilization efficiencies on the liquid film surface were calculated with the same reaction area but various parameters, such as the length of the linear light source, the light source distance from the surface and the length-to-width ratio of the reactor. The results indicate that the light source distance was the most sensitive parameter among all the parameters of the linear light source and the flat plate reactor, and the irradiance distribution tended to be more uniform while the light utilization efficiency decreased rapidly when the distance became greater. Thus the proper distance should be determined by weighing the advantage and disadvantage. The irradiance of an UV tube as the linear light source in experiments was measured in the middle area and the edge area on the liquid film surface of the reactor. The measured light irradiance was basically consistent with the calculated value under the experimental conditions.