流体动力自动清洗螺旋纽带的污垢清洗力矩研究

采用运动合成与试验测量相结合的办法,对安装自动清洗螺旋纽带后传热管风的水流流动进行了分析,利用动量矩定理建立了自动清洗螺旋纽带的动力矩理论计算式,由此导出螺旋带的结构优化原则,这些原则测量所得结果一致。     

凝汽器自动除垢强化换热装置的应用

介绍了一种自动除垢强化换热装置在电厂汽轮机凝汽器上的应用,分析了其原理及应用效果,通过应用此装置能减小传热端差,提高汽轮机负荷。     

凝汽器水下清洗机器人的PLC系统设计与实现

介绍凝汽器水下清洗机器人的PLC系统设计与实现,阐述该系统的结构及硬件组成.完成从PLC系统的硬件配置到应用程序设计,给出PLC系统的结构图、电气原理图和工作流程图.     

水冷设备污垢特性及其最佳清洗周期研究

水冷设备由于污垢影响,在运行过程中制冷量下降,功耗增加,必须进行定期清洗.如何确定清洗周期对提高机组经济性能具有重要意义.根据水冷设备机组运行曲线,提出以最大平均COP来确定其最佳清洗周期的方法,并将其应用于实际中.     

软测量技术在凝汽器真空特性模型中的应用研究

分析了软测量技术的原理、类型、建模方法及流程等内容,给出了凝汽器真空的软测量模型。以300Mw机组凝汽器运行数据为基础,通过分析影响凝汽器真空的各种因素,获取了建立软测量模型的辅助变量,并利用最小二乘方法建立了具体的凝汽器真空特性软测量模型。该模型以在现场投入实际应用,运行效果良好,能到满足用户的实际需求。     

气溶性射流对钢板污垢清洗的应用研究

为了获得更好的清洗效果和节能环保,提出了一种新型的射流方式——气溶性射流。基于流体力学和气溶性射流的工作原理,根据气溶性射流的特性和喷嘴的几何特征,研究了气液相的流动特性方程,得到了气溶性射流的速度分布规律。利用自行设计的超音速喷嘴组装的带电气溶性射流实验装置对钢板进行清洗,经简易检测表明：气溶性射流喷嘴产生的超音速极大地提高了洗涤效率,与同流量的喷嘴相比,效率提高近10倍,具有广泛的应用前景。     

适用于孔板送风的孔板阻力特性研究

为了提高孔板送风房间流场预测的准确性,采用数值模拟结合试验验证的方法,以局部阻力系数为评价指标,分别对不同开孔形状、孔板厚度、孔口直径、开孔率的孔板的阻力特性展开了研究。结果表明：开孔形状对局部阻力系数影响较小,随着当量直径的增大,局部阻力系数略微增加,5种常见开孔形状下的平均局部阻力系数最大值与最小值偏差为4.5%;随着孔板厚度的增大,局部阻力系数减小,孔板厚度在1～3 mm范围内,平均局部阻力系数最大值与最小值偏差为17.8%;随着孔口直径的增大,局部阻力系数增加,直径在4～10 mm范围内,平均局部阻力系数最大值与最小值偏差为15.1%;随着开孔率的降低,局部阻力系数显著提高,且两者之间存在幂函数的变化关系。通过对数据进行分析,得到了适用于开孔率范围为0.01～0.05的孔板局部阻力系数近似计算式,该式为孔板送风房间流场预测提供了一定的数据基础。     

润滑脂阻力特性和降压特性测定的研究

润滑脂输送特性－管路阻力特性及降压特性，是润滑工程系统设计计算不可缺少的设计参数之一，我国尚未进行这方面的研究和测定。本文以油脂阻力特性和降压特性的测定方法作了探讨论证，根据本文的论证，太原润滑液压研究所已设计研制了阻力特性和降压特性的测定装置，同时用该装置测定了１＃极压锂基脂的阻力特性并经实验通过鉴定。为国内添补了空白。     

风圈式风量调节阀阻力特性的模拟研究

为研究风圈式风量调节阀阻力系数与阀门开度半径的函数关系,以DN200的风圈式风量调节阀为研究对象,运用FLUENT对其进行数值模拟,对不同开度半径下的阀门流场和阻力系数进行分析,得到了阀门阻力系数与阀门开度半径的函数关系式。结果表明:阀门开度半径大于0.05m时,阻力系数小并且曲线变化平缓,阀门开度半径小于0.05m时,阻力系数大并且曲线陡峭变化,阀门阻力系数随着阀门开度半径减小呈指数性增长。     

活塞式调节阀阻力特性的试验研究

叙述了活塞式调节阀阻力特性试验的原理，设备，步骤，结果和结论。对应用的雷诺相似原理和阻力平方区理论做了较为详尽的阐述。对活塞式调节阀的设计与阻力系数试验具有一定一指导意义。     

Development of an apparatus for removing magnetic sludge by permanent magnets setup in the condenser of the power plant

In this paper, permanent magnets are used to remove magnetic sludge in the condenser of the power plant. To obtain the flow characteristics and magnetic information that are needed for determining a proper design of the magnetic sludge removal apparatus, we performed numerical simulations through the use of two commercial codes, ANSYS Workbench-Emag and CFX. We also performed experiments on various kinds and sizes of magnets to obtain the magnetic information through a gauss meter. By analyzing the results of simulations and experiments, the minimum magnetic force that is able to remove the any size of the magnetic sludge in the condenser was calculated, and the design of the removal apparatus was confirmed. We made the test model which was confirmed by the simulations and experiments for the tests of efficiency of the removal apparatus. After testing, the test results were compared with those of numerical simulations and have good agreements.     

An investigation on the wear resistance of high strength concretes

In this study, a relationship was determined between the mechanical properties (compressive and splitting tensile strengths) and wear resistance of high strength concretes (HSC) having compressive strength between 65 and 85 MPa. For this purpose, 108 test specimens were produced from six different mixtures. After 28 days standard curing, compressive strength, splitting tensile strength, and wear resistance tests were performed on the specimens. From the test results, mathematical expressions were developed to estimate the wear resistance of concrete regarding their compressive strength and splitting tensile strength. As result a reliable relationship was produced from this properties.     

Impacts of fouling and cleaning on the performance of plate fin and spine fin heat exchangers

An experimental study was conducted to investigate the effects of air-side fouling and cleaning on the performances of various condenser coils used in unitary air-conditioning systems. A total of six condenser coils with different fin geometry and row number were tested. Performance tests were performed at three different conditions: clean-as-received, after fouling, and after cleaning. In all cases, it was observed that the fouling was mostly confined to the frontal face of the heat exchanger as reported in the previous investigations. The amount of deposited dust was more dependent on fin geometry for the single-row heat exchangers than for the double-row heat exchangers. The predominant effect of fouling was to cause a more significant increase in air-side pressure drop than a degradation in heat transfer performance. For the single-row heat exchangers, the pressure drop increased by 28 to 31%, while the heat transfer performance decreased by 7 to 12% at the standard air face velocity of 1.53 m/s depending on fin shape. For the double-row heat exchangers, the pressure drop increased by 22 to 37%, and heat transfer performance decreased by only 4-5% at the same air face velocity. Once the contaminated coils were cleaned according to the given cleaning procedure the original performance of the heat exchangers could almost be recovered completely. The pressure drop could be restored within 1 to 7% and the heat transfer performance could be recovered to within 1 to 5% of the originally clean heat exchangers. Therefore, it is concluded that a periodic application of the specified cleaning technique will be effective in maintaining the thermal performance of the condenser coils.     

视觉图像在擦窗机器人位置检测中的应用

介绍了一种新型吊蓝式高层建筑擦窗机器人系统，该系统已成功用于高层建筑玻璃幕墙请洗作业中。在简单介绍了机器人结构、工作过程和控制系统组成后，着重对视觉图像在擦窗机器人位置检测中的应用进行了详细讨论，利用Sobel算法对玻璃窗框进行边缘检测和提取，井在实际使用中收到了满意效果。     

CFD analysis of effects on fluid flow resistance of metallic wavy structures

Microscale wrinkles can be utilized to enhance the characteristics of products. For example, a shark skin having riblet surface can move faster underwater, minimizing fluid flow resistance. We introduce a novel approach to fabricate microscale metallic wrinkles using a soft lithography and electroforming process; we also evaluated the effects of wrinkles by computational fluid dynamics (CFD) analyses. For the generation of metallic wrinkles, a UV-curable resin, NOA68T was used to fabricate a master wrinkling pattern by mechanism of compressive forces on a skin of the weakly polymerized resin layer. The master pattern was molded and replicated as metallic wrinkles on a surface via soft lithography and electroforming processes. To understand the advantages of a wavy surface on reduction of flow resistance, we carried out two- and three-dimensional (2D and 3D) CFD analyses. The drag coefficient of a wrinkled 2D square model was decreased about 17.1 %, and a 3D real wrinkle model showed 4.9 to 7.3 % reduction of it compared to without wrinkle models. We believe that it is possible to reduce the fluid flow resistance using wavy surfaces that can easily be generated selectively or wholly on an arbitrary surface.

     

An investigation into the effects of installation on the performance of insertion flowmeters

An electromagnetic and a turbine insertion flowmeter were tested in three different flow conditions inside a 0.590-m bore pipe inserted in the National Engineering Laboratory (NEL) large water flow measurement facility. The results were compared with velocity measurements obtained from a laser Doppler velocimeter (LDV). The advantage of using such a reference measurement is that LDV is non-intrusive and does not affect the velocity profile itself.Of the meters tested, one was supplied with a whole meter calibration factor and the other was supplied with a calibration factor for the D/2 position.For both meters, application of the respective manufacturer's blockage correction improved the velocity measurements, reducing the differences between the LDV and corrected insertion meter measurements and the difference between the integrated insertion meter measurements and the gravimetric measurements.Swirling and skew flow profiles were generated by the installation of the NEL designed swirl generator and flow disturber, respectively. Neither of these disturbed profiles affected the performance of either of the meters in terms of accuracy of measurement compared with the LDV readings. The profiles themselves, however, changed the velocities at the D/8 and 7D/8 points, making single point estimates of the mean velocity inappropriate. A complete 13-point traverse, integrated using the method of cubics as described in BS 1042 [1] (Section 2.3: Measurement of fluid flow in closed conduits, 1992), gave acceptable estimates of mean velocity in both swirling and skew flow for both probes.     

核电站温度仪表应用分析

结合福清核电一期工程中温度仪表的选型设计,比较了核电站常用测温仪表的不同特点以及1E级与NC级温度传感器技术要求,从量程和精度上分析了温度仪表的设计需求,并规范了核电站测温元件套管的选型和应用要求。其经验和方法对其他工业温度仪表应用有一定的参考意义。     

An investigation on the erosion resistance of rare earths nitrocarburized 40 Cr steel

The effect of rare earths (RE) on erosion resistance of nitrocarburized 40 Cr steel is investigated. Results indicate that a significant improvement occurs in erosion resistance of nitrocarburized 40 Cr steel by introducing RE in nitrocarburizing processes comparing conventional nitrocarburizing processes. Measurement of mechanical properties exhibits that both hardness and toughness of nitrocarburized 40 Cr steel increase in the case using RE nitrocarburizing processes comparing the conventional. Metallurgical microscopy reveals that there is an improvement in the nitrocarburizing layer microstructure attributed to an introduction of RE in nitrocarburizing, which results in an improvement in erosion resistance and mechanical properties. Surface morphology observation of tested samples reveals that predominantly furrow-like peeling from plastic deformation are observed in RE nitrocarburizied 40 Cr steel, while the furrow-like peeling with initial cross crack and large grinding peelings takes place in conventionally nitrocarburized samples.     

新型无功补偿自动控制器在大功率索道中的应用

无功功率补偿是电力系统中的一项重要工程。通过设计无功自动控制器来实现并联电容器组的投切,保证功率因数在给定的合格范围内变动,完成无功功率的补偿。设计以CS5460A为核心芯片,从电网中检测到和功率因数相关的参数(电功、电流、有功功率)送主控单元,CPU计算出功率因数,将其和功率因数上下限比较,发出投切电容器的命令。     

An investigation into the effects of the hierarchical structure of tendon fascicles on micromechanical properties

During physiological loading, a tendon is subjected to tensile strains in the region of up to 6 per cent. These strains are reportedly transmitted to cells, potentially initiating specific mechanotransduction pathways. The present study examines the local strain fields within tendon fascicles subjected to tensile strain in order to determine the mechanisms responsible for fascicle extension. A hierarchical approach to the analysis was adopted, involving micro and macro examination. Micro examination was carried out using a custom-designed rig, to enable the analysis of local tissue strains in isolated fascicles, using the cell nuclei as strain markers. In macro examination, a video camera was used to record images of the fascicles during mechanical testing, highlighting the point of crimp straightening and macro failure. Results revealed that local tensile strains within a collagen fibre were consistently smaller than the applied strain and showed no further increase once fibres were aligned. By contrast, between-group displacements, a measure of fibre sliding, continued to increase beyond crimp straightening, reaching a mean value of 3.9 per cent of the applied displacement at 8 per cent strain. Macro analysis displayed crimp straightening at a mean load of 1 N and sample failure occurred through the slow unravelling of the collagen fibres. Fibre sliding appears to provide the major mechanism enabling tendon fascicle extension within the rat-tail tendon. This process will necessarily affect local and cellular strains and consequently mechanotransduction pathways.