水平吸水管悬空高对泵站进水池进水特性影响

针对某些大型泵站进水池进水特性不良,泵站运行效率严重下降等问题,采用ICEM-CFD软件来构建泵站进水池三维模型并进行网格划分,利用计算流体力学中的Fluent软件,基于标准的k-ε湍流模型,对泵站进水池流态进行了数值模拟,并研究了水平吸水管悬空高对泵站进水池进水特性的影响。研究结果表明:水平吸水管悬空高与泵站进水池的进水特性关系密切,适当增加水平吸水管悬空高能够明显改善进水池的进水特性,然而一味地增大吸水管的悬空高的做法并不可取,因此,推荐泵站水平吸水管的悬空高取值范围为1.2~1.5 D。

南北方污水处理厂进水水质特性分析

选取低碳氮比的两座污水处理厂进行南北方污水处理厂进水水质特性分析,并相应提出了初沉池优化运行的建议。两座污水处理厂进水碳源不足的问题均比较突出,对于生物脱氮系统,进水中均为碳氮比的影响最大。进入雨季,相对于旱季两座污水处理厂进水水质和水量均有所变化,但变化幅度有明显区别。两座污水处理厂进水有机物、氮和磷的日变化规律不相同,极值出现的时间也有所不同,但有机物浓度均主要受到非溶解性有机物浓度影响。两座污水处理厂进水中有机物组分比例不同,北方污水处理厂溶解性易生物降解碳源比例高,非溶解性慢速不可生物降解碳源比例低。两座污水处理厂根据进水水质特征采用不同的生物处理工艺,出水水质均能稳定达标。

天津滨海新区工业带污水厂进水水质特性分析

为掌握天津市滨海工业带污水厂进水水质特性变化规律,选取天津滨海新区的6座污水厂,于2017年11月~2019年12月对其进水定期取样测试,进行进水水质特征分析,研究了COD、氮、磷组分结构,以及碳氮比、氯离子、UV254变化规律。结果表明:①滨海新区污水厂受工业废水影响,进水中均含有不同程度的有机氮、有机磷、芳香烃及共轭体系的化合物,增加了后续生物处理的难度;②6座污水厂氯离子浓度较高,应根据进水特性,注重提高生物系统的抗冲击性能、采取必要的防腐措施;③针对新区各污水厂的提标改造,需要充分掌握水质运行规律,对于个别污水厂进水碳源不足的现象,提标工程应设置碳源投加系统,为后续生物处理工艺正常运行提供保障,确保水质达标。

上海天山污水处理厂进水水质动态特性分析

根据上海天山污水处理厂的进水水质特性分析,并相应提出优化运行的建议。

连云港大浦污水处理厂进水数据统计和分析

城市污水处理厂设计规模与进出水标准是决定污水处理厂的工艺类型、构筑物规模、工程投资和运行效果的重要因素.现在已建成的大部分城市污水处理厂往往因为进水负荷动态变化较大,使设计水量或水质普遍与实际运行情况有较大的差异,降低了投资效益的同时,也严重影响了运行效率.因此,对污水处理厂进水水质的历史数据进行整理,并据此得到有价值的统计和分析结果,对控制工程建设投资、降低运行和管理费用具有重要意义.对连云港大浦污水处理厂的进水特性进行分析,基于分析结果所确定的水质现状,可为该厂高效运行提供参考依据,也为新的污水厂设计提供信息.

旋流分离器在合流制溢流污染控制中的应用进展

指出了合流制溢流污水严重地影响着水环境质量和水生生态系统安全,在合流制溢流污染的末端控制中,旋流分离器因占地面积小、建设费用低等优点在欧美等国家得到了广泛应用,但国内目前尚处于起步阶段。检索了3种在欧美广泛使用的旋流分离器(Storm King、EPA旋流浓缩器、FluidsepTM)的应用,分析了结构参数、操作参数、进水水质特性等对旋流分离器分离效果的影响,并探讨了我国应用旋流分离器的可行性及需要重视的问题。

Validation of the Monte Carlo Model Designed to Simulate the Neutronic Characteristics of Advanced Boiling Water Reactor Assembly

In the last few years, interest in burnup calculations using Monte Carlo methods has increased. Previous burnup codes have used diffusion theory for the neutronic portion of the codes. Diffusion theory works well for most reactors. However, diffusion theory does not produce accurate results in burnup problems that include strong absorbers or large voids. MCNPX code based on Mont Carlo Method, is used to design a three dimensional model for a BWR fuel assembly in a typical operating temperature and pressure conditions. A test case was compared with a benchmark problem and good agreement was found. The model is used to calculate the distribution of pin by pin power and flux inside the assembly. The effect of axial variation of water （coolant） density, and of control rods motion on the neutron flux and power distribution is analyzed. The effect of addition of Gd2O3 to natural uranium （0.711%） on both the thermal neutron flux and normalized power are analyzed. The concentration of U^235, U^238, Pu^239, and its isotopes is also calculated at burn-up 50 GWD/T.

Uncertainty and Sensitivity Analysis for the HELIOS Loop within the LACANES Benchmark

Within the OECD/NEA Benchmarking of Thermal-Hydraulic Loop Models for Lead-Alloy Cooled Advanced Nuclear Energy Systems （LACANES）, the Institute for Neutron Physics and Reactor Technology takes part in the validation process of system codes and the characterization of the thermal-hydraulic behavior of an experimental loop operated with liquid lead-bismuth-eutectics. To confirm the calculations, the results were compared to experimental data obtained from the HELIOS facility at the Seoul National University and to the results of other benchmark participants. The comparison showed that the calculations are within measurement tolerance but nevertheless discrepancies among the participants exist. The pressure drop estimation is determined by a variety of empirical correlations for the friction and the form loss coefficients. Hence, uncertainty and sensitivity measures were applied to find out which parameter is more relevant for the overall pressure drop. In the frame of this investigation, the system code TRACE and the software system for uncertainty and sensitivity, SUSA, were used. The results show that the total pressure drop varies between -30 and ＋15% related to the reference case.