|
|
|
| Effects of propeller layout position on flow characteristics in oxidation ditch |
| CHEN Bin1, WANG Bingqi1, ZHANG Hua1, WANG Qiang1, WANG Zhen2 |
| 1.Research Institute of Chemical Machinery, HeFei University of Technology, Hefei, Anhui 230009, China; 2.NanJing LanShen Pump Co.Ltd., Nanjing, Jiangsu 211500, China |
|
|
|
|
Abstract To avoid sludge deposition in a running track type oxidation ditch, the layout position of four propellers is altered when the pool structure remains unchanged. The steady fluid flow field in the whole ditch is simulated by means of STARCCM+ software plus the standard k-ε turbulence model when these propellers are in operation. The velocity distribution in each section in the ditch and the velocity distribution in the whole flow field as well as the dead water zone are analysed to specify the optimal propeller layout position for the pool. Results show that the propellers′ position has a great influence on velocity distribution, and a too large or too small distance between a propeller and the middle baffle wall can lead to an uneven velocity distribution and an enlarged dead water zone. Especially, when the distance is about 0.85 times the sum of the circular baffle wall radius and the distance of the circular baffle wall centre to the middle baffle wall, the average fluid velocity is as high as 0.35 m/s in the major sections observed with the smallest dead water zone. Flow separation zones are inevitable at the back of the circular baffle wall and the two ends of middle baffle wall, but they can be diminished by changing propellers′ position. In addition, there is an obvious vortex phenomenon in the corners of the ditch by virtue of the interaction between the propellers and the pitch walls.
|
|
Received: 18 November 2015
|
|
|
|
| [1]邓荣森.氧化沟污水处理理论与技术[M].北京:化学工业出版社,2010.[2]区岳州,胡勇有.氧化沟污水处理技术及工程实例[M].北京:化学工业出版社,2005.[3]陈志澜,杨人卫.导流墙偏置位置对氧化沟性能影响的分析[J].环境科学与技术,2010,33(10):162-165. CHEN Zhilan, YANG Renwei. Effect of eccentric position of guide wall on oxidation ditch performance[J].Environmental science and technology,2010,33(10):162-165.(in Chinese)[4]刘启龙,何建京.水下推动器对氧化沟流场特性影响的实验研究[J].环境科学与技术,2012,35(11):93-98. LIU Qilong, HE Jianjing.Submergedpropeller′s influence on oxidation ditch flow characteristics [J]. Environmental science and technology,2012, 35(11):93-98.(in Chinese)[5]唐瑜谦,何建京,刘启龙.水下推动器作用下氧化沟流场的数值模拟[J].水动力学研究与进展,2013,28(3): 317-323. TANG Yuqian, HE Jianjing,LIU Qilong. Numerical simulation of flow fields in an oxidation ditch of taking a submerged propeller as the power [J]. Chinese journal of hydrodynamics, 2013, 28(3):317-323.(in Chinese)[6]张亚磊,张法星,张敬威,等.基于ADV的推流式曝气池流场特性研究[J].四川大学学报(工程科学版),2014,46(2):29-34. ZHANG Yalei, ZHANG Faxing,ZHANG Jingwei,et al. Study of flow field characteristics in plug-flow aeration tank based on ADV[J].Journal of Sichuan University(engineering science edition),2014,46(2):29-34.(in Chinese)[7]陈立爱,汪家权,候红勋.氧化沟半宽导流墙偏心距对水力特性的影响[J].环境科学与技术,2013,36(11):130-135. CHEN Liai, WANG Jiaquan,HOU Hongxun. Hydraulic regime of oxidation ditch affected by half-width guide wall eccentricity[J].Environmentalscience and technology,2013,36(11):130-135.(in Chinese)[8]陈立爱,汪家权,候红勋.氧化沟叶轮与中间导流墙间距对流场的影响研究[J].给水排水,2013,39(2):127-132. CHEN Liai, WANG Jiaquan,HOU Hongxun.Study of oxidation ditch propeller and mid-wall spacing effect on flow field[J]. Water supply and drainage,2013,39(2):127-132.(in Chinese)[9]孔凡博,张耀宗.三槽氧化沟内底推位置与积泥厚度的分析研究[J].环境工程,2013,31(4):6-12. KONG Fanbo, ZHANG Yaozong. Research on the position of the underflow propeller and the deposition thickness in the triple oxidation ditch[J].Environment engineering,2013,31(4):6-12.(in Chinese)[10]KJH. Controlling sludge settleability in the oxidation ditch process[J].Water research, 2008, 42(6/7):1459-1466.[11]SIMON S, ROUSTAN M, AUDIC J M, et al. Prediction of mean circulation velocity in oxidation ditch.[J]. Environmental technology, 2001, 22(2):195-204.[12]LI L, NI J. Three-dimensional three-phase model for simulation of hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification in an oxidation ditch[J]. Water research, 2014, 53(8):200-214.[13]WICKLEIN E, ROFERS K,HUNT R, et al. CFD modeling of activated sludge mixing in an oxidation ditch conversion[C]//Proceedings of the water environment federation′s annual technical exhibition and conference, 2013.[14]李明,李明高.STAR-CCM+与流场计算[M].北京:机械工业出版社,2011.[15]潘志庚,庞明勇.几何网格简化研究与进展[J].江苏大学学报(自然科学版),2005,26(1): 67-70. PAN Zhigeng, PANG Minyong. Survey for decimation of geometric meshes [J].Journal of Jiangsu University(natural science edition), 2005, 26(1):67-70.(in Chinese)[16]田飞,施卫东,陈斌,等.污水处理搅拌机的水力设计与试验研究[J].流体机械,2011,39(6):1-4. TIAN Fei,SHI Weidong,CHEN Bin,et al. Hydraulic design and experimental study on the waste water treatment mixer [J].Fluid machinery,2011,39(6):1-4.(in Chinese) |
|
|
|
