基于环型射流抽吸原理的新型预掺混扩散器稀释特性初探
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摘要
预掺混扩散器区别于常规扩散器,在污水自扩散器出流前提前掺入环境水进行预稀释,可有效提高污水射流初始稀释度、减小混合区范围。本文通过调研分析,总结归纳了管壁开孔式、套管式及终端式这三类已有预掺混扩散器的工作原理,提出制约预掺混扩散器应用推广的主要因素是稀释效果欠佳、水头损失过大。在此基础上,提出基于环形射流抽吸原理的预掺混扩散器,并采用模型试验与三维数值模拟方法初步研究了污水径向进流与切向进流两种结构型式扩散器的流量放大倍比及紊动掺混效果。研究结果表明,这两类进流方式的预掺混扩散器均可有效实现环境水对污水的提前掺混,其中切向径流效果更优。
Different from the conventional diffuser,the pre-dilution diffuser mixes the ambient water into the wastewater before it is discharged from the outfall, which can effectively enhance the initial dilution and narrow the mixing zone. Based on the investigation in previous studies, this paper summarized the working principles of the following three types of pre-dilution diffusers: Wall hole type,Casing pipe type,and Terminal type,meanwhile pointed out that the main factors restricting the application and popularization of pre-dilution diffusers are poor dilution effect and excessive head loss. On this basis,two pre-dilution diffusers based on the principle of annular jet suction were proposed,and the flow amplification ratio and turbulent mixing effect of two structural diffusers with radial inlets and tangential inlets were preliminarily studied by model tests and three-dimensional numerical simulation. The results show that the pre-dilution diffusers of these two kinds of inflow modes can both achieve the early mixing of the environmental water to the sewage,but the tangential inlets has better performance in dilution. Subsequent research will be further conducted on improving the premixing capability,increasing the turbulent intensity and entrainment area of sewage jet,and reducing head loss.
Different from the conventional diffuser,the pre-dilution diffuser mixes the ambient water into the wastewater before it is discharged from the outfall, which can effectively enhance the initial dilution and narrow the mixing zone. Based on the investigation in previous studies, this paper summarized the working principles of the following three types of pre-dilution diffusers: Wall hole type,Casing pipe type,and Terminal type,meanwhile pointed out that the main factors restricting the application and popularization of pre-dilution diffusers are poor dilution effect and excessive head loss. On this basis,two pre-dilution diffusers based on the principle of annular jet suction were proposed,and the flow amplification ratio and turbulent mixing effect of two structural diffusers with radial inlets and tangential inlets were preliminarily studied by model tests and three-dimensional numerical simulation. The results show that the pre-dilution diffusers of these two kinds of inflow modes can both achieve the early mixing of the environmental water to the sewage,but the tangential inlets has better performance in dilution. Subsequent research will be further conducted on improving the premixing capability,increasing the turbulent intensity and entrainment area of sewage jet,and reducing head loss.
引文
[1]张爱玲,王韶伟,赵懿珺,等.滨海核电厂温排水环评关键问题分析[J].环境影响评价,2015,37(3):49-52.
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[14] ARGAMAN Y,GALIL N,VAJDA M. Use of jet pumps in marine waste disposal[J]. Journal of the Environmental Engineering Division,1975,101(5):703-711.
[15] PORTILLO E,LOUZARA G,ROSA M R D L,et al. Venturi diffusers as enhancing devices for the dilution process in desalination plant brine discharges[J]. Desalination&Water Treatment,2013,51(1/3):525-542.
[16] AGG A R,WHITE W R. Devices for the Pre-dilution of sewage at submerged outfalls[J]. Proceedings of the Institution of Civil Engineers,1974,57(1):1-20.
[17] AGG A R,BRUCE F E,ACKERS P,et al. Discussion. Devices for the pre-dilution of sewage at submerged outfalls[C]//Proceedings of the Institution of Civil Engineers,1974,57(4):799-818.
[18] HANSEN J,SCHRODER H. Horizontal jet dilution studies by use of radioactive isotopes[J]. Acta Polytechnica Scandinavica-civil Engineering and Building Construction Series,1968(49):5.
[19] SHARP J J,WHITE W R,DANIEL R J,et al. The use of a buoyant wall jet to improve the dilution of a submerged out fall[J]. Ice Proceedings,1976,61(1):247-250.
[20] NOUTSOPOULOS G C,YANNOPOULOS P C. Axial Dilution in Obstructed Round Bouyant Jet[J]. Journal of Hydraulic Engineering,1989,115(1):71-81.
[21]平浚.射流理论基础及应用[M].宇航出版社,1995.
[22]步玉环,王瑞和,周卫东.旋转射流流动规律研究[J].石油钻采工艺,1997,19(2):7-10.
[2]陈晓秋,商照荣.核电厂环境影响审查中的温排水问题[J].核安全,2007(2):46-50.
[3] World Bank Group,World Health Organization. Pollution Prevention and Abatement Handbook,1998:Toward Cleaner Production[M]. World Bank Publications,1999.
[4] United States Environmental Protection Agency. Clean Water Act NPDES Permitting Determinations for Thermal Discharge and Cooling Water Intake from Mirant Kendall Station in Cambridge[R/OL]. 2004-06-08[2017-9-14]. https://www3.epa.gov/region1/npdes/mirantkendall/assets/pdfs/draftpermit/Kendall_Determin-Doc_06_08_04.pdf.
[5]夏青.污水海洋处置工程设计理论与方法[M].北京:中国环境科学出版社,1996.
[6]张永良,阎鸿邦.污水海洋处置技术指南[M].北京:中国环境科学出版社,1996.
[7]黄菊文,徐连军,韦鹤平.污水海洋处置稀释扩散河工模型试验装置[J].同济大学学报(自然科学版),2002,30(12):1487-1491.
[8]国延恒,严忠民.竖管式扩散器排放近区数值模拟研究[J].水利水电科技进展,1998(3):39-41.
[9]徐高田,韦鹤平.量纲分析对污水近区初始稀释度变化规律的探讨[J].上海环境科学,1997(10):24-26.
[10] NECE R E,GOLDSTERN P P,BLACK J L. Single-port suction manifolds[J]. Journal of Hydraulic Division,1966,92(1):43-64.
[11] SHARP J J. Limitations of devices to improve dilution of ocean outfalls[J]. Proceedings of the Institution of Civil Engineers,1978,65(4):935-940.
[12] SILVESTER R. Jet mixers in sewage outfalls[J]. J. Inst. Eng. Aust.,1967,39:33-37.
[13] SHARP J J. Mixing tubes for improving dilution at small outfalls[M]//Recent Research Advances in the Fluid Mechanics of Turbulent Jets and Plumes. Springer Netherlands,1994:479-487.
[14] ARGAMAN Y,GALIL N,VAJDA M. Use of jet pumps in marine waste disposal[J]. Journal of the Environmental Engineering Division,1975,101(5):703-711.
[15] PORTILLO E,LOUZARA G,ROSA M R D L,et al. Venturi diffusers as enhancing devices for the dilution process in desalination plant brine discharges[J]. Desalination&Water Treatment,2013,51(1/3):525-542.
[16] AGG A R,WHITE W R. Devices for the Pre-dilution of sewage at submerged outfalls[J]. Proceedings of the Institution of Civil Engineers,1974,57(1):1-20.
[17] AGG A R,BRUCE F E,ACKERS P,et al. Discussion. Devices for the pre-dilution of sewage at submerged outfalls[C]//Proceedings of the Institution of Civil Engineers,1974,57(4):799-818.
[18] HANSEN J,SCHRODER H. Horizontal jet dilution studies by use of radioactive isotopes[J]. Acta Polytechnica Scandinavica-civil Engineering and Building Construction Series,1968(49):5.
[19] SHARP J J,WHITE W R,DANIEL R J,et al. The use of a buoyant wall jet to improve the dilution of a submerged out fall[J]. Ice Proceedings,1976,61(1):247-250.
[20] NOUTSOPOULOS G C,YANNOPOULOS P C. Axial Dilution in Obstructed Round Bouyant Jet[J]. Journal of Hydraulic Engineering,1989,115(1):71-81.
[21]平浚.射流理论基础及应用[M].宇航出版社,1995.
[22]步玉环,王瑞和,周卫东.旋转射流流动规律研究[J].石油钻采工艺,1997,19(2):7-10.