水深对曝气过程中氧总转移系数的影响

水处理曝气过程传氧速率的有关计算没有考虑水深对氧总转移系数KLa的影响.经过理论分析,导出了由水深引起的KLa变化的修正系数计算公式.理论计算表明,水深对KLa有较大的影响,从而对传氧速率有较大的影响.这种影响在曝气过程的有关计算中不应忽略不计.为验证水深对KLa的影响,进行了曝气充氧的试验.理论分析的结果与试验结果比较接近,表明可以采用由理论分析得出的公式对KLa修正计算.在曝气深度为2.5-4.5 m的范围内,修正系数的范围为0.78-0.86.

Influence of Water Depths on Volumetric Oxygen Transfer Coefficient in Aeration

The influence of water depths on volumetric oxygen transfer coefficient(KLa) is not taken into account in the calculation of oxygen transfer rate in aeration as yet.The modification coefficient formula of volumetric oxygen transfer coefficient(KLa) is derived from theoretical analysis.The theoretical analysis results make clear that water depths have a significant impact on volumetric oxygen transfer coefficient and oxygen transfer rate.The impact of water depths on volumetric oxygen transfer coefficient has to be taken into account in the calculation of oxygen transfer rate in aeration.The aeration experiment was carried out to verify the impact of water depths on volumetric oxygen transfer coefficient.The volumetric oxygen transfer coefficient has to be modified in the calculation of air volume.The experimental results accord with theoretical results.The formula obtained from theoretical analysis can be used to calculate modification coefficient of volumetric oxygen transfer coefficient.In general,the modified volumetric oxygen transfer coefficient is between 0.78 and 0.86 when the water depth is between 2.5 and 4.5 m.