侧伸式搅拌槽中叶轮区的局部速度  

Local area velocities in a tank with side-entering impellers

作　　者：朱磊[1] 黄雄斌[1] 郑晓东[1] 

机构地区：[1]北京化工大学化学工程学院,北京100029

出　　处：《北京化工大学学报（自然科学版）》2010年第6期7-13,共7页Journal of Beijing University of Chemical Technology(Natural Science Edition)

摘　　要：采用φ2m×4.2m侧伸式搅拌槽,研究了搅拌器在0.6m水位时的最佳安装位置下(三桨均匀分布,最佳偏转角βopt=10°,垂直夹角α为6°,推流桨安装高度h为0.75D,推流桨伸入长度与推流桨直径之比L/D=1.44)的局部速度。结果表明:搅拌槽内流体流速仅在槽内桨叶排液区较大;与立式推流桨的流场(轴对称,双峰值)相比,无论单桨还是三桨,侧伸式推流桨的流场不是沿轴线对称的;三桨同时启动时叶轮的排出流量准数Nqd为0.665,并外推得到单桨排出流量准数约为三桨排出流量准数的91.0%;在竖直方向上,叶轮排液区合速度和轴向速度的均值变化在左侧与右侧一致,而在叶轮上半部分与下半部分不对称;实验回归出单桨合速度与轴向距离的关系是V*=0.402Y*-0.151,三桨同开时V*=0.454Y*-0.049。Local area velocities have been studied in a tank of φ2 m×4.2 m with side-entering impellers under the optimal installation location （3 impellers were the average layout; the horizontal angle of deflection βopt=10°; the vertical angle α=6°; the impeller installation height h=0.75D,and the ratio of the entering length and the impeller diameter L/D=1.44）. The results showed that the velocities in the tank are relatively large in the area close to the three impellers. The velocities in a tank with side-entering impellers are different from the flow field in a vertical agitated tank with an axially symmetric,double peak velocity distribution. When just a single impeller was rotating,the peak of velocity on the measurement line of Y＊≈1 was moved left to the axis line of the impeller,while when the three impellers were rotating at the same time,the peak of velocity was moved left over the axis line of the impeller to -0.16R. The proportion V＊a/V＊ in a tank with side-entering impellers is larger than the proportion V＊a/V＊ in a tank with a vertical plug impeller,while the proportions of V＊t/V＊ and V＊r/V＊ vary in an opposite manner. It was shown that the velocities became closer to the axial velocities with increasing axial distance; the discharge flow number （Nqd） of three impellers was 0.665,and the estimated value of the discharge flow number （Nqd） of a single impeller was about 91% of that of three-impellers. In the vertical plane with an axial distance close to the impeller,the changes in the mean velocity and the axial velocity in the right part of the impeller zone were similar to those in the left part of the impeller zone,but the change of velocities above the half-way line is different from that below （the proportion of discharge flow above the half-way line is 44.2% and the proportion of discharge flow of below is 55.8%）. The relationships between the velocity and axial distance can be fitted as V＊=0.402Y＊-0.152 for a single impeller and V＊=0.454Y＊-0.049 for thr

关 键 词：侧伸式搅拌 烟道气脱硫 流场 

分 类 号：TQ027[化学工程]