CAJ | 학술논문

在圆柱形沉降筒中利用多层格栅产生近似各向同性紊流场，研究盐水和淡水中紊动对黏性泥沙絮凝沉降的影响，分析絮团粒径、体积含量和泥沙浓度变化．研究结果表明：在相同剪切率条件下，和在淡水中相比，盐水中黏性泥沙絮凝时间缩短，絮团粒径增加，然而盐度对絮团体积含量影响并不明显；最大絮团粒径随着紊动剪切率的增加先增大后减少，最大絮团粒径对应的紊动剪切率在盐水中为20.8,s-1，淡水中为15.6,s-1；随着紊动剪切率的增加，水体中泥沙平衡浓度增大，达到平衡所需要的时间缩短．
재원주형침강통중이용다층격책산생근사각향동성문류장，연구염수화담수중문동대점성니사서응침강적영향，분석서단립경、체적함량화니사농도변화．연구결과표명：재상동전절솔조건하，화재담수중상비，염수중점성니사서응시간축단，서단립경증가，연이염도대서단체적함량영향병불명현；최대서단립경수착문동전절솔적증가선증대후감소，최대서단립경대응적문동전절솔재염수중위20.8,s-1，담수중위15.6,s-1；수착문동전절솔적증가，수체중니사평형농도증대，체도평형소수요적시간축단．
An array of oscillating grids was applied in the cylindrical settling column to generate quasi-isotropic tur-bulence flow. The experiments were carried out to clarify the influences of turbulence on cohesive sediment floccula-tion and settling in salt water and fresh water. The floc size distribution,volume fraction and suspended sediment concentration were analyzed based on the experimental results. The results show that the flocculation time is shorter and the floc size is larger in salt water than those in fresh water. However,the effect of salinity on the floc volume fraction is not obvious under the same shear rate conditions. The maximum floc size firstly increases,then decreases with increasing shear rate. When the maximum floc size is formed,the shear rates are 20.8,s-1 and 15.6 s-1in salt wa-ter and fresh water,respectively. Furthermore,with the increase of the shear rate,the sediment equilibrium concen-tration increases and the time required for equilibrium decreases.