排涝泵站轴流泵进、出水流道的数值模拟

针对杭州三堡排涝泵站的轴流泵装置,选取两种典型的进、出水流道设计方案(斜20°和斜30°方案),在设计流量工况下对整个轴流泵装置进行了非定常数值模拟,通过比较内部流态和水力损失确定了最佳方案,并在非设计流量工况下对最佳方案进行非定常数值模拟分析。结果表明,在设计流量工况下,与斜20°方案相比,斜30°方案中水泵的内部流态更好且水力损失更小,为最佳方案;对于斜30°方案,在大于和小于设计流量的工况下,轴流泵的出水流道水力损失均大于设计流量工况下的,且偏小流量工况下的水力损失最大。     

大型潜水泵站竖井式出水流道的水力性能研究

大型潜水泵站竖井式出水流道优化设计的目的是尽可能地避免涡流及其他不良流态在出水流道内产生,减少出水流道水力损失。探讨了潜水泵与长轴泵扬程测试方法的不同,并指出了潜水泵站流道损失与长轴泵站的区别。以1600HQB-40大型潜水混流泵为例,利用ANSYS软件,对3种不同类型的出水流道进行了数值计算,获得了不同出水流道的水力特性分布规律。根据计算结果,对于不同形式的局部出水管路,推荐损失系数ζ取值在5.0~8.0左右。     

大型给水泵站进、出水流道数值模拟及优化设计

根据某给水泵站设计参数要求,设计具有相同进、出口尺寸的肘型和簸箕型2种进水流道方案,以及7种不同龟背形式和倒圆弧半径的出水流道方案。数值计算采用压强连接的隐式修正SIMPLEC算法,并结合雷诺平均法的RNGκ-ε模型和壁面函数法。计算结果表明,在相同进、出口尺寸条件下,肘型进水流道的水力损失比簸箕型进水流道小73.7%;有龟背和圆弧的出水流道的水力损失最小。该研究实现了进、出水流道的优化设计。     

肘形进水流道优化水力设计研究

进水流道的主要作用是调整水流流态,为水泵的叶轮室进口提供良好的水力条件。如果进水流道内流态不良,有可能产生脱流、漩涡等现象,使得水泵叶片压力分布不均匀,从而导致水泵的效率降低、水力损失增加,更有甚者水泵产生汽蚀,引起泵站的振动,威胁泵站的安全运行。采用数值模拟方法,分析水泵叶轮、进水流道隔墩以及进水流道几何参数对流道水力性能的影响。     

空调喷口内部流道型线对射流流场的影响

利用FLUENT 6.1模拟软件对4种不同内部流道型线的喷口的流速分布、喷口轴线流速、喷口出口断面流速、喷口出口断面的总压及静压进行了数值模拟,对喷口内部流道型线对射流流场的影响进行了研究。     

基于实验和模拟方法对隔板絮凝池流场的研究

运用粒子图像测速技术和数值模拟方法,对往复式隔板絮凝池的流场进行了研究,通过分析实验结果和数值模拟结果,从流场的水力特性角度解释了往复式隔板絮凝池无效能量消耗大、絮凝效率低的根本原因。     

全液压转向器流场特性分析与结构改进

基于全液压转向器在使用过程中振动、噪声大的问题,从转向器内部流场角度入手,采用流体动力学软件FLUENT对转向器内部进行流场特性的分析,得到了转向器的速度及压力分布图,通过分析,找出产生振动、噪声的原因。提出了转向器内部流道的改进方案,并对改进后的流道模型再次进行分析,显示流场特性得到了改善,从而验证了方案的可行性,为转向器的结构优化设计提供了理论依据。     

侧堰式溢洪道水力特性三维数值模拟

对某水库的侧堰式溢洪道的泄流能力、水力特性进行了模型试验研究。试验结果表明:侧槽式溢洪道的侧槽内产生较大环流,水流流场紊乱、流态复杂;在设计水位和校核水位下沿程水深均小于设计边墙高度;WES堰堰面无负压、且溢洪道沿程无负压,不会引起空蚀破坏。使用Fluent软件建立RNG k-ε模型对侧堰式溢洪道进行数值模拟计算,将计算结果与试验结果进行分析对比,发现模拟结果与试验结果较为一致。研究成果可为Fluent数值模拟在溢洪道的应用中提供参考。     

穿孔旋流絮凝池污泥斗高度对絮凝条件的影响

通过改变穿孔旋流絮凝池中污泥斗的高度和絮凝池的尺寸,利用计算流体动力学(CFD)数值模拟对絮凝池内部流场和流态特性进行分析;以涡旋速度梯度、湍动能和湍动能耗散率作为絮凝评价指标,研究污泥斗高度对絮凝水力条件的影响,并确定不同处理规模的絮凝池所对应的最优污泥斗高度。将数值模拟结果与设计手册的参考值进行对比,发现模拟得到的污泥斗高度最优值比设计手册中提供的污泥斗高度参考值低10 cm,这在一定程度上减少了絮凝池施工的工程量,降低了工程造价,且更加有利于絮凝池的运行管理。     

基于SolidWorks流场计算分析在雨水泵站设计中的应用

以斯里兰卡首都科伦坡城区北部1座设计、建造流量为30 m^3/s的雨水泵站为实例,运用SolidWorks软件工具确定泵站设计、工艺参数,建立3D模型、水力模型、流场数值仿真模型等,进行水力流体仿真模拟,重点通过模型几何创建、边界条件设定、网格剖分对泵站雨水流入、排出过程中水泵水头损失和侧进侧出式泵站布局下的渠道上下游水流场流态作了计算与数据分析,依靠仿真模拟手段完成结构设计和优化并对设计数据进一步作了验证,保证了雨水泵站正常运行,实际应用效果显著。     

The Design of Conventional and Siphonic Roof-Drainage Systems

The hydraulic principles governing the performance of conventional and siphonic roof-drainage systems are described and compared. The flow rate in a conventional system is determined by the depth of water in the gutter or on the roof. Siphonic systems are able to achieve higher flow rates because they make full use of the head available between the roof and the discharge point at ground level.
Some special operating characteristics of siphonic systems are described and recommendations are made on the factors that should be considered in their design.     

边坡虹吸排水数值模拟方法及应用

边坡虹吸排水是处于探索应用阶段的新技术。基于广义达西定律与渗流场分析的基本原理,将“以管代孔”法与解析单元法相结合,提出针对虹吸排水系统的数值模拟方法。按照流量和水头等价的原则,给排水孔赋予等效的渗透系数,并根据虹吸排水原理确定其内水头边界条件,以此模拟虹吸排水过程。建立边坡三维渗流有限元计算模型,以单个排水孔为例,计算虹吸排水作用前、后坡体内地下水位线与渗流场分布的变化,揭示了虹吸排水对边坡地下水渗流场的影响规律。在排水孔径和孔长恒定的条件下,模拟了排水孔位置变化对排水效果的影响,结果表明边坡虹吸孔位选择对排水效果有重要影响。     

Case study: the performance and design outline of a buffering stormwater drainage system for a low-lying area

Performance evaluation and safety assessment of a buffering stormwater drainage system (BSDS) for a low-lying area are discussed in this paper. Unlike a conventional pump drainage system, the BSDS, which drains stormwater runoff of a low-lying area to a nearby channel system through underground conduits with gravity, and then buffering peak flows with the storage capacity of a channel system, will discharge stormwater to rivers outside the low-lying area with pumps or flood gates if necessary. This kind of drainage system is considered to be environment friendly and economic both in terms of capital cost and operating & maintenance expenses. To investigate the design parameters and evaluate the performance and safety of BSDS, a hydraulic model coupling the conduit systems and a channel system was developed in this paper, and a case-study approach based on field investigation and simulation test was used. Moreover, the design requirements for safety of BSDS were drawn through a simulation test.     

高程差对高压燃气管线水力计算结果的影响

本文根据《城镇燃气设计规范》（GB 50028—2006）,利用管道仿真软件Pip曲ncstudio中气体模拟器TGNET对忠县至丰都的高压燃气管线分别进行了按水平管和按实际高程计算通过能力的稳态模拟。通过对水力计算结果的分析,提出了高压燃气管线的水力计算应根据不同的起点与终点压力差和管线沿途高程差选择相应的燃气管道计算公式或长输管道计算公式。     

沉淀池多斗排泥系统的设计

建立了沉淀池多斗排泥管水力计算简易公式。经分析论证,该水力计算公式是成立的。同时,揭示了多斗排泥的某些规律和特性,在结构上延伸了水力计算公式的内涵,并提出了在排泥工况下排泥管内存在一个水力闭合环及流量逆形成两个观点,可为沉淀池多斗排泥水处理系统的设计及运行管理提供参考。     

虹吸式屋面雨水排水系统热点问题探讨

虹吸式屋面雨水排水系统已在国内的大、中型项目中广泛应用,笔者就虹吸满管流的定义、设计重现期、虹吸系统中的水流流态及适用的计算公式、悬吊管的最小安装高度、自清流速等争议较大的热点问题进行了探讨.     

双曲线冷却塔空气流场分析及结构优化选型

本文综合研究了冷却塔塔内外空气流场的分布特性 ,为了适应和改善流场 ,提出冷却塔结构设计亟待解决的 8个方面的课题。从结构设计服从于服务于水工工艺出发 ,充分发挥结构选型的优势 ,塔内最大限度地适应并改善、流场 ,消除全部涡漩。使 2种流体 :冷空气和热水雾 (滴 )之间热交换率最高。塔外加肋或调整群塔间距及布置型式减小风荷载体型系数 ,使冷却塔结构设计施工总工程量最省。以上分析可以认定抛物线塔型最好 (风洞模型试验后 ) ,抛物线冷却塔将比双曲线冷却塔冷却效果优越的多     

深埋长大引水隧洞三维物理模型渗透性试验研究

 地质力学物理模型试验是研究地下工程问题的主要方法之一。结合锦屏二级水电站引水隧洞工程,对高渗透压下深埋引水隧洞进行施工过程的物理模拟,设计制作水压自动控制供水系统,离散式花管渗流生成系统,实现渗流场的高度仿真模拟。对动态施工过程中引水隧洞围岩内部的渗流及演化规律进行计算分析,实体模型内特征点的渗透压力计算值、实测值比照结果证明模型渗流试验系统的科学性和合理性。试验结论为引水隧洞的防渗施工技术设计提供理论依据,并对引水隧洞的长期稳定性、安全性评价和预测具有重要意义。     

Numerical simulation of the dynamic operation of multi-outlet siphonic roof drainage systems

Although siphonic roof drainage systems have been installed in Europe since the 1970s, the design of such infrastructure is still based on steady state theory. Such approaches are only truly applicable at the design condition, under specific rainfall conditions, and cannot be used to assess the response of siphonic systems to alternative rainfall conditions and/or operational scenarios. Previous research at Heriot-Watt University led to the development of a numerical model capable of accurately simulating the performance of single outlet systems under a range of different conditions. The work reported herein details the logical extension to this work; i.e., the development of a numerical model to simulate the performance of multi-outlet siphonic roof drainage systems. The experimental work undertaken to assist in the development of the new model boundary conditions is briefly described, and relevant results are illustrated. The development of the numerical model is then detailed, and model output is presented. Finally, conclusions are drawn regarding the developed model, and plans for future work are outlined.     

Estimating flow rates through individual outlets of siphonic roof drainage systems

An experimental investigation is used to quantify the flow rates through individual outlets of multi-outlet siphonic roof drainage systems under both full-pipe and partially filled pipe flow conditions. A pressure transducer and a propeller-type current meter were installed within each tailpipe to measure water depth and flow velocity. The study tests the hypothesis that it may be possible to predict accurately the flow rates through individual outlets of multi-outlet siphonic roof drainage systems. A new technique of estimating flow rates is trialled by comparing instantaneous pressure transducer and current meter readings with previously calibrated flow data to find the best data match. The study results were very positive and clearly demonstrate that the underlying methodology was appropriate and that it may be possible to model numerically the individual outlet flow rates in multi-outlet siphonic roof drainage systems.