封闭式紫外线消毒器光强计算及分布规律研究

Distribution and calculation of ultraviolet intensity in a closed channel ultraviolet disinfection reactor

提出了大型封闭式紫外线消毒器光强的计算方法并研究了光强分布规律。当n0根紫外灯均布在半径为R0的圆柱面上时,反应器内任意点光强关于n0+1个平面对称,任意横截面上的光强均沿n0个平面对称。反应器最大光强位于其中垂面与石英套管外表面的交线上,紫外灯环形阵列内侧最小光强位于反应器端面中心点处,而阵列外侧的最小光强位于端面与相邻两根紫外灯交点连线的中垂线沿端面与反应器内壁的交点处。介质吸光度对反应器平均光强和光强分布的影响显著,反应器平均光强随介质吸光度的增大而降低,反应器内及反应器截面上任意点光强的不均匀系数则随之增大。反应器的平均光强相同时,提高消毒效果的关键是采取必要的措施使消毒器内的水流处于紊流状态,从而使病原菌受到相同程度的紫外线辐射。

A calculation method is proposed to determine the intensity and to analyze the intensity distribution in a closed channel ultraviolet disinfector.When n0 ultraviolet lamps are evenly distributed on a hypothetical cylinder surface with radius of R0,the arbitrary points' intensity inside the reactor are symmetrical by n0+1 planes while cross-section intensity are symmetrical by n0 planes.The maximum ultraviolet intensity could be calculated at the points in intersection curves of the reactor perpendicular plane and the outer surfaces of the quartz sleeves.The minimum ultraviolet intensity inside the annular ultraviolet lamps' array could be determined at the central point of end surface,while that outside the annular ultraviolet lamps' array could be calculated at the points where the perpendicular line to connection line between two intersection points of two adjoining lamps' axes and end surface is intersected with the inner wall of the reactor.Volume-averaged intensity and intensity distribution are affected significantly by the absorbance of media in the reactor,and volume-averaged intensity decreases with the increasing absorbance of media while nonuniformity coefficients that is the ratios of maximum and minimum intensity in cross-sections or in the reactor increase with it.When average intensity in different reactors is equal,necessary measures should be used to make water or wastewater turbulent in the reactors,thus microorganisms would receive the same ultraviolet dose of radiation.