周向后弯叶片对轴流泵噪声辐射特性的影响

采用混合模拟方法研究了叶片周向后弯对轴流泵水动力性能和噪声辐射特性的影响,计算中考虑了声场与结构振动的耦合作用,获得叶片周向后 弯角对水泵水动力性能和声场辐射特性的影响曲线。结果表明,仅通过叶轮叶片的周向后弯不能有效提高水泵的扬程和效率,但可以降低水泵向外辐射 的噪声。该结果对低噪声水泵设计具有一定的参考价值。     

水力射流泵在埕岛西平台的应用

埕岛西平台是综合性采油平台,平台采油方式为水力射流泵和电潜泵采油两种,用生产水和水源井产出液为动力液的水力射流泵采油效果很好。水力射流泵运行周期长、检泵作业量少、生产效率高、动力液用量少,可使采油成本降低。文中对水力射流泵在埕岛西平台的成功应用的经验进行了总结。     

旋片式机械真空泵的设计计算及测量

一 、前言 旋片式机械真空泵,乃是一个偏心转子中,含有中间夹有弹簧的二个叶片,在定于内回转,使其定子内腔容积周期的扩大与缩小,达到吸气与排气之目的,进行工作的真空设备。 旋片式机械真空泵,是真空技术中最基本的真空获得设备之一,它可供冶金、化工、轻工、石油、医药、电器和科研等部门生产与试验用,也可作为油扩散泵、油增压泵和分子泵的前级泵。 目前,国内生产这种泵的厂家很多,各厂所产泵的性能均很稳定,生产的品种已经系列化。在国外生产这种泵的国家也很多,所产泵的性能与我国所产泵的性能不差上下。有的国家生产的品种均已系列化…     

斜盘连杆式疏水泵组的噪声与振动试验

为了解斜盘连杆式疏水泵组的噪声与振动特性,建立了疏水泵的AMESIM模型,根据泵组的结构及工作原理,对疏水泵的阀口压力脉动特性和泵组的噪声和振动源进行分析,得出主要振动源频率。对疏水泵系统的噪声与振动进行试验研究,测试了系统的噪声和振动加速度。试验结果表明泵组噪声源主要为电机振动、减速箱振动、吸水管路扰动,而配流阀的撞击噪声对泵组振动与噪声的影响不大。试验结果为疏水泵组的减振降噪提供了试验依据。     

离心泵快速启动过程瞬态性能测试系统的研制

离心泵在快速启动过程中表现出明显的瞬态特性,其瞬态水力性能与稳态运行过程的性能存在较大区别,快速启动的试验研究对于离心泵在特殊场合应用打下重要基础。由于其测试方法与一般水泵试验方法存在明显区别,因此专用试验台的研制是瞬态性能试验的重要基础。文中介绍试验系统的整体结构和数据采集系统,以及瞬时流量、扬程、转速等参数的测试方法和瞬态汽蚀特性的测试方法,同时还给出了各瞬态性能数据的描述方式和修正方法。通过在该试验台上进行的多次试验的结果可以看出,该试验台能较准确地测试离心泵的瞬态特性和稳态性能。     

某核级一次水事故泵抗震性能评估的振动台试验研究

由于一次水事故泵运行条件下的振动台试验可评估抗震性能,用钢丝橡胶波纹管连接进出口水管、沙堆支撑橡胶管提供柔性约束。合理模拟水泵在试验过程中所受接管荷载,保证试验过程中水泵与循环水箱变形协调。对正常运行的事故泵进行5次OBE、1次SSE人造地震动输入振动台试验,并据动应变曲线判断仍处于弹性状态。试验表明,经5次OBE、1次SSE人造地震动输入后的一次水事故泵仍能保证压力边界完整性及功能可运行性。较试验前各项功能指标无明显变化,抗震性能良好。     

离心泵的常见故障及处理

离心泵在制药生产企业应用十分广泛，运行中易发生各种故障。按工作介质分类，油泵可分为通用油泵、冷油泵、热油泵、等泵。耐腐蚀泵可分为耐蚀金属泵、非金属泵、杂质泵，如水泵可分为清水泵、锅炉给水泵、热水泵等。离心泵经过长时间运行，而使性能下降时，必须有计划的检查维修与保养，以防范于未然。     

通用小型汽油机进排气系统流通特性与排放性能研究

欧美国家对通用小型汽油机排放法规不断加严,目前中国生产的不同批次通用小型汽油机排放性能差异较大已是行业共有的技术难题.油气混合气浓度对通用小型汽油机排放影响很大,利用作者开发的通用小型汽油机进排气系统稳流试验台,对不同汽油机气缸盖进排气道、空滤器等进行稳流试验,对试验数据进行分析,得出进排气系统流通特性的差异和不同批次的生产波动是批量生产小型汽油机混合气浓度改变和排放性能差异的主要原因.研究结果还表明：通用小型汽油机采用压铸气缸盖,进排气道结构受压铸工艺的限制,流通系数偏低,影响发动机性能的提高,进一步提高进排气系统性能是优化通用小型汽油机性能的一个重要途径.     

空调水系统并联水泵的选择配置与分析

分析了空调水系统中水泵选择时应注意的方面,并通过泵的性能曲线(两台水泵为例)与水管道特性曲线对定频泵并联、定频泵,变频泵并联、变频泵并联三种组合方式下水泵的运行状况进行了分析,通过对比得出三种组合方式中变频泵并联方式最为节能,定频泵、变频泵并联次之,定频泵并联节能较差.     

进水泵房自控系统说明

净水厂进水泵房的作用是为水厂一二期和三期以及水厂绿化提供水源,本文从进水泵房的控制模式、流量调节、压力调节、水泵的停机保护、水泵的自动启泵控制及自动停泵控制等方面进行了介绍,综述了进水泵房在各个方面的控制特点。     

State-of-the-art technology in variable compression ratio mechanism for spark ignition engine

Present investigations deal with development of a novel variable compression ratio (VCR) mechanism and its implementation in a small and relatively large size single-cylinder engines. Operation of this mechanism is found to be smooth and effective in the running condition of the engine as well. This mechanism, when incorporated in the small size spark ignition HONDA engine, portrayed improvement in engine performance with increment in compression ratio (CR) for petrol and kerosene. Their respective optimum CRs 5.02 (petrol) and 5.27 (kerosene) are higher than the base value 4.8. In case of large size KIRLOSKAR engine, the present VCR mechanism is found to be useful while operating with liquefied petroleum gas (LPG), where measurements showed that combustion duration is lower with LPG for CR 9.79 as compared with base value 9.0. The present experiments clearly demonstrate the usefulness of VCR mechanism in improving engine performance for a given fuel and broadening the range of alternative fuels burnt in the engine. Ease of fabrication, simplicity in installation, accessibility in troubleshooting and smooth run-time alterations are the advantages with the current novel mechanism.     

Effect of atmospheric altitude on engine performance

The air capacity and the fuel consumption of a four-cylinder four-stroke petrol engine have been measured. Tests have been conducted at engine speeds from 1000 to 4000 rpm and at atmospheric altitude from 600 to 850 m above the sea-level as well as at ambient pressure from 0.9 to 0.95 bar. The performance of the engine at low speeds is different from that at high speeds. At low engine speeds up to 2500 rpm the air capacity, the fuel consumption and the volumetric efficiency decreases with increases of engine altitude by which the ambient pressure decreases. However at higher speeds engine than 3000 rpm the engine performances decreases with decreases of engine altitude and so with increases of atmosphere pressure. A 200 m change on the altitude of the engine, corresponding to a change in atmosphere pressure of about 3000 Pa, may lead to change fuel consumption and volumetric efficiency up to 40%. It is shown that to obtain maximum engine efficiency and minimum fuel consumption, fuel mixture should be varied with respect to the altitude of engine. The knowledge about the altitude effect could therefore lead to improve the performances on engine development and design.     

电动汽车和相关电源材料的现状与前景

论述了电动汽车（EV）、电动汽车用镍氢电池、锂离子电池、质子交换膜燃料电池（PEMFC）、固体氧化物燃料电池（SOFC）及相关材料的研发现状、产业化前景，指出以电动汽车代替燃油内燃机汽车，以氢能代替碳基燃料，是当前运输业的主要发展方向。     

Modern trends in heat pump development

Modern trends in heat pump development are discussed. Motor/compressor units are now being designed specifically for heat pumps. The use of solar heat, direct fired domestic heat pumps (eg with natural gas), the Stirling engine and Rankine cycle heat pump are being investigated.     

Influence of air intake pipe on engine exhaust emission

The exhaust emissions of a four-cylinder four-stroke petrol engine have been measured. Tests have been conducted at engine speeds ranges from 1000 to 4000 rpm and at air intake pipe diameters of 20, 25, 30, 35, 40 and 63 mm. The results demonstrate that the concentrations of the hydrocarbon (HC) and that of the carbon monoxide (CO) are relatively high at small air intake pipe diameter of 20 mm and at low engine speed of about 1000 rpm. Both pollutants have a minimum at large air intake pipe diameter of about 63 mm and at high engine speed of about 4000 rpm. The exhaust emissions HC and CO increase also as the ambient pressure decreases and as the altitude of the engine increases. The values of carbon dioxide (CO₂) and the oxygen (O₂) remain relatively constant at a wide range of different operating conditions. Therefore the knowledge about the effect of the above parameters could lead to improve the emission control technology as well as the engine performance on engine development and design.     

PLC在水源热泵变频节能系统中的应用

水源热泵用地下恒温水源代替冷却塔,具有高效节能的特性。但在实际应用中,还应充分考虑主机、冷冻水泵及冷却水泵等高耗能设备的节能问题。本文重点阐述水源热泵系统中冷冻水和冷却水系统的变频节能原理、闭环节能控制方案和控制系统的设计。     

Study on Failure Analyses and Material Characterizations of a Damaged Booster Pump

Pumps are a key and crucial part of many industrial units which usually are endangered by metallurgical, mechanical, and chemical damages. The most important mechanisms of failure in pumps are cavitation, erosion, and corrosion which directly are influenced by pump’s materials, type of fluent, and operation condition. The aim of this study was to investigate the role of material selection in the main failure mechanisms of a power plant booster pumps. To observe the kind and micro structure of pumps optical microscopy and image analyses software were used. Morphology of the pumps’ body is investigated by scanning electron microscopy. Electrochemical tests and water analyses are done for measurement of corrosion rate as well as amount of particles in feed water. Moreover, tensile testing was carried out to compare the mechanical properties of body alloy with standard alloy. The results revealed that cavitation and erosion were the most significant mechanisms. On the other hand, the data from analyses and observations clarified that the material which chosen for pumps alloy was improper which was accompanied with lack of fabrication technology.     

Exergy analysis of electrically- and thermally-driven engines to drive heat pumps: An exhaustive comparative study

The choice of driving a heat pump with an electrically- or a thermally-driven engine is a vexing question complicated by the carbon footprint and environmental impact of using electricity versus natural gas (or waste heat) as the main driver for the respective engines. Useful work generated by these two distinct engines is the focal point of this paper, addressing a key question: which engine presents a better choice for a given heat pumping application within the constraints of energy and environmental stewardship? We examine this question comprehensively through the methodology of energy, exergy, and availability analysis, explaining clearly, why the output of work from these two distinct engines is inherently vastly different. Thermodynamic consistency is guaranteed by satisfaction of the First and Second Laws applied to closed systems and their subsystems. The general conclusion is that thermally-driven engines are not industrious converters of heat to mechanical work, for heat pumps.     

Ethanol-containing automotive fuels – a safety concept for petrol stations in Germany

Due to the promotion of renewable energy sources, the demand for ethanol/automotive fuels has increased, whereby the ethanol is produced from biomass. As these fuels are flammable liquids, explosion protection concepts are needed for their transport, use and storage and for the operation of petrol stations. Safety characteristics are the basis of such concepts. Since the data for ethanol, on the one hand, and for automotive petrol, on the other hand, differ considerably, the relevant data for the ethanol/automotive petrol mixtures have to be determined and the existing explosion protection concepts will possibly have to be limited or modified. For this reason the correlations between the necessary safety characteristics – flashpoint, boiling point, auto-ignition temperature, maximum experimental safe gap, upper explosion point – and the mixing ratio of ethanol and automotive fuel have been investigated. Based on the results of this investigations, those concentration limits are elaborated for which the existing safety concepts remain valid. For mixtures with an ethanol content going beyond such limits, suitable safety measures and requirements regarding explosion-protected equipment are derived. The changes that are necessary with respect to the safety concept of petrol stations when ethanol/automotive petrol mixtures are offered instead of or in addition to pure petrol are explained.     

Die Flüssigkeitsring-Vakuumpumpe als verfahrenstechnische Maschine

Liquid ring vacuum pumps have many and diversified applications in the process industry. Primarily they are used to transfer gases and vapours from a lower to a higher pressure level. Due to the specific principles of operation, a heat and mass transfer between the gas or vapour and the sealing liquid takes place also. This can be utilised to perform unit operations. Beside transportation and compression of gases the pump can perform the following operations: exchange of heat, condensation/evaporation, absorption/desorption as well as chemical reactions. Because of these features is the liquid ring vacuum pump a ?process engine”? and an interesting alternative to other process apparatus. Following the definition of H. Brauer (1985) is the objective function of a process engine achieved by a moving element, whereas the objective function of a process apparatus is achieved without any moving element. For nearly all possible combinations of sealant, gases and vapours reliable empirical principles to determine the suction volume and the power requirements of liquid ring vacuum pumps are at hand. Besides has the use of liquid ring vacuum pumps to perform unit operations a long successful tradition. However, the field of applicability can be enlarged if the feasibility of the engine for individual unit Operations can be predicted with the help of physical models. Due to the eccentrically arranged rotor a sickle shaped space is formed between rotor hub and liquid ring where suction, compression and discharge of an gas/vapour mixture can be realised if the suction and discharge slots are arranged in a suitable manner. As the seal liquid is in direct contact with the gases and vapours all reactions inside the pump develop in the direction of a thermodynamical equilibrium between the two phases. An important consequence of this feature is the limit of operation of liquid ring vacuum pumps: the suction pressure has to be above the vapour pressure of the seal liquid. Another consequence is the possibility to utilise this type of pumps for unit operations. The turbulent surface of the liquid ring which is formed by a dense hale of droplets is ideal for heat and mass transfer processes. Following an attempt of C. Pfleiderer, the azimuthale distribution of the static pressure and the contour of the liquid ring can be determined under considerably simplifying assumptions. One of these simplifications is that the condensation and evaporation in the pump is neglected. The further simplifications deal with the significant idealisation of the geometry. Taking back the simplifying assumptions step-by-step and including the thermodynamical circumstances it is possible to calculate the azimuthale distribution of the static pressure and the real contour of the liquid ring for the condensation and the evaporation. These attempts can be carried on to taking several components in the vapour-portion of the gas/vapour mixture into account and form the basis of the calculation of the absorption and desorption. In this case the assumption that the thermodynamical equilibrium is attained instantly is no longer valid.