矢流洁净室的模型实验与数值模拟

针对矢流洁净室这种新型、节能的洁净室，本文用数值摸拟和模型实验两种方法对其进行了研究．模型实验实测了空态和静态两种工况下模型矢流洁净室室内流场和浓度场，给出了流场图和浓度场实测结果；数值模拟方法，根据ｋ─ε紊流模型，采用有限差分法，对两种工况下矢流洁净室室内流场和污染物的分布进行了计算机求解，得出室内流场图及污染物分布特性．通过对两种方法所得结果进行分析和比较，证明了矢沈洁净室净化的基本原理，得出矢流洁净空室内流场特点有利于其达到较高级别洁净度，且浓度场实测结果证明该种洁净空可以达到较高级别的洁净度。建议某些场合推广使用矢流洁净室。     

矢流洁净室的数值模拟

本文以工程中广泛使用的Ｋ－ε紊流模型为基础，采用有限差分法，对矢流洁净室三维紊流流场和污染物深度场进行了数值模拟。通过对大量算便的计算结果的对比分析，进一步认清了矢流洁净室内气流的流动特性和污染物的分布规律，得到了这种洁净室的主要设计参数，并给出了扇形送风口边界条件的处理方法。本文为矢流洁净室的设计及其在国内的推广使用提供了依据。     

矢流洁净室静态模型实验研究

本文对矢流洁净室进行了静模型实验研究,实测了静态工况下模型间内的速度场,并在室内设置点污染源,实测了室内浓度场,得出了这种洁净室的污染物分布特性。实验结果表明,矢流洁净室内气流流型属于空气洁净技术中较为合理的气流流型。     

矢流洁净室的模型实验研究

本文对矢流洁净室进行了模型实验研究。建立了矢流洁净室模型实验台,实测了矢流洁净室的速度场和浓度场,并测出矢流洁净室的气流流型。对实验结果进行分析和比较,得出矢流洁净室室内流场的基本特点。浓度场的实验结果表明,矢流洁净室可以达到较高级别的洁净度。矢流洁净室可应用于实际工程中。     

矢流洁净室二维流场的大涡模拟

采用大涡模拟技术对矢流洁净室二维流场进行了数值模拟，分析了模拟结果，确定了空态洁净室的送风口半径、回风口高度、送风速度等参数，指出湍流大涡模拟能准确得到洁净室流场中旋涡的位置和尺度，适用于对洁净空调多种工作环境的数值模拟。     

矢流洁净工作台数值模拟

采用Ｋ－ε紊流教学方程及壁面函数法，对矢流洁净工作台的速度场、浓度场进行了数植模拟，得出操作区内气流流动特性和污染分布规律，给出优化尺寸，论证了矢流用于洁净工作台的可行性和优越性。     

悬浮颗粒数值模拟模型改进研究

分析了目前气粒两相流模拟研究中所使用的方法和模型，针对洁净室内悬浮颗粒极为稀疏的特点，提出了一个改进的颗粒模型，该模型中将颗粒相处理为连续介质，采用当地颗粒湍流动能与浓度梯度来模拟颗粒的扩散。用此模型对全顶棚送风下部两侧回风洁净室内悬浮颗粒的分布进行了模拟计算，与浓度模型模拟所得结果比较发现，改进模型不但在精度方面有明显提高，而且与实验值吻合良好。     

关于洁净室最小采样量的探讨

本文分析了我国（洁净厂房设计规范）与美国标准（ＦＳ２０９Ｄ）有关最小采样量的理论依据．比较了洁净室粒子按普阿松分布与按ｔ分布计算的最小采样量的结果．讨论了１００级洁净室不同采样速率引起差异的原因．     

层流洁净室采样问题的分析

本文以理论公式为基础，分析计算了层流洁净室中亚微米粒子非等动力采样所产生的相对误差值；通过在洁净风洞中的实验研究，得出了非等动力采样所引起的误差，指出对层注以洁净室检测应遵守等动力原则。     

ISPE规范和制药行业洁净室

分析了制药系统污染物的来源与控制方法，介绍了ISPE规范中对不同工艺洁净区净化等级的划分和对制药洁净室材料的要求。对制药行业暖通空调系统设计中的一些问题进行了讨论，根据ISPE规范的相关规定，给出了相应的建议。     

虹口港、杨浦港地区旱流污水截流工程设计水量的论证

对虹口港、杨浦港地区近几年来产业结构调整 ,污染大户的外迁 ,工业废水量明显减少的情况进行调研 ,通过对现状污水量的采集 ,规划、现状水量的测定等进行了详细的分析和论述 ,比较客观合理确定虹口港、杨浦港地区旱流污水截流工程的设计污水量     

工作流设计案例分析——房产管理系统中的工作流设计

工作流的设计概念应用到软件系统中,将工作过程分解成任务、角色,按照一定的规则来执行这些任务并对它们进行监控,可以提高办事效率、降低房产管理成本,提升企业经营管理水平和企业市场竞争力。房产管理系统中借鉴工作流的概念,可有效地提高管理人员的技术水平。     

变频调速与管网叠压供水系统小流量工况分析与对策探讨

在用水低谷期出现的生活给水系统小流量是造戍水泵运行效率低下、影响变频供水系统节能效果的重要因素之一.通过实测数据分析验证了变频调速供水系统在小流量工况下的高能耗现象;在分析变频调速泵特性曲线的基础上分别推求出满足水泵高效运行和变频可调速的最小流量,为水泵的选取提供理论依据;结合实例阐述了克服小流量不利影响的技术措施.     

An analysis of compartment fire doorway flows

A mathematical study is made to compute the doorway flow behavior due to fire in a room. Two approaches were taken, first a model attempting to include the effect of fire entrainment and vent mixing; second was a model based on an ideal point source plume fire—both in the zone model concept. Limiting analytic results were found for the latter to give insight into the physics. The results were compared to available flow data, and an approximate formula was developed to predict the doorway mass flow rate to within 20% for a wide range of fire conditions. CFD computations were also explored using FDS. Results are compared from FDS and the zone model with experimental data for a wide range of variables.     

水利工程明渠均匀流水力计算探讨

结合工程实例,阐述了水利工程明渠均匀流的计算方法及计算注意事项,对其中的有关水力专业名词及计算作出详细解释.     

Characterization of two-phase flow in a single rock joint

An experimental study using a triaxial apparatus was used to analyze the two-phase flow patterns in jointed rock specimens. Rock specimens having a single natural fracture were tested for two-phase flow of water and air. Triaxial tests were conducted to characterize the two-phase flow through fractured granite specimens at low confining pressures. It was found that for a relatively smooth joint (JRC<6), bubble flow pattern occurred within the rock joint when the gas velocity is below 15 m/s. The average velocity of water usually varied between 0.1 and 0.5 m/s for bubble flow patterns. In this velocity range, air bubbles were able to form along the joint walls or to be randomly displaced within the water phase. When the gas velocity inside the rock joint exceeded 22 m/s, the flow patterns took annular form for non-zero capillary pressures (i.e., injected gas pressure is not equal to injected water pressure). At elevated (>0.25 MPa) gas injection pressures, the gas occupied the main part of the fracture and the liquid was able to flow as an unstable film forming an annular flow along the joint. When the annular flow developed, the mixture flow pattern was independent of the air flow velocity. This was due to the fact that once the injected air velocity reached a critical value (i.e., 20 m/s), water velocity inside the joint was negligible for a given confining pressure and injected water pressure. Further increase in inlet air pressures developed a single-phase air flow with no water flow.     

供热系统中调节阀的研究与应用

依据调节阀流量特性的数学方程，导出了流量特性分别为直线型和等百分比型调节阀流通截面积的计算公式，指出了现有调节阀阀芯形状设计中存在的问题，分析了供热系统中调节阀的选用原则，认为应根据流通能力来计算选择调节阀的口径，而不是由连接管的管径来确定，并认为调节阀的安装地点不同，其计算公式中的系数有差别。     

Study on performance of horizontal single pass shell and multi-tube heat exchanger with baffles by air bubble injection

ABSTRACT

The single pass shell and multi-tube heat exchanger with double segmental baffles'’ performance improvement were experimentally investigated by two methods of air injection into shell side when an increase in air bubble created an effect in the corresponding values of shell and tube heat exchanger such as the overall heat transfer coefficient, effectiveness, NTU and the pressure loss. In the first method, air bubble injection into shell side was parallel to the cold water flow; also in the second method, air bubble injection into shell side was cross flow to the cold water with different air flow rates to calculate approximately the most favourable performance conditions. 1–6?LPM of air flow rates and 10–20?LPM shell side water flow rates were transformed with constant tube side hot water flow rate.     

The importance of gully flow modelling to urban flood simulation

ABSTRACT

Urban flood simulation often ignores or simplifies the function of underground gully systems due to data and computational limitations. To discover the influence of gullies on urban flooding, a novel approach is proposed in this study, by fully-coupling a 1D gully flow model (GFM), a 1D sewer flow model (SFM), and a 2D overland flow model (OFM) to simultaneously simulate the flow exchanges between surface, gullies and sewer pipes. This fully-coupled approach is compared with a simplified approach which directly introduces surface water into sewer pipes without being via gullies. The validation results show that the fully-coupled approach considerably reduces the underestimation of flood extent by 27% compared with the simplified approach. Without considering the capacity of lateral tubes between gullies and sewer pipes, the simplified approach over-drains the surface water into sewer pipes. The modelling of gully flow is crucial for correctly evaluating the efficiency of drainage systems.     

水环热泵空调水系统变流量节能控制探讨

针对传统空调系统设计负荷偏大、系统运行过程中水系统输送流量不能随室内负荷变化而变化的情况,在引入流量差异系数的基础上,认为对水环路采用流量控制可以达到节能的目的.