某供热机组锅炉给水泵液偶改变频调速汽蚀安全性分析

文中对某2×300 MW及2×330 MW供热机组锅炉给水泵液力偶合器改变频器调速方案进行了现场调研,计算了变频改造后各种工况下除氧器至给水泵入口段的管路损失,并结合前置泵的运行数据对给水泵入口有效汽蚀余量和必须汽蚀余量进行了校核计算。结果表明:变频改造后,其前置泵转速在1 000~1 490 r/min范围内变化时,给水泵组入口有效汽蚀余量均大于其必需汽蚀余量。该改造方案能够满足给水泵组汽蚀安全性要求。     

给水泵和给水前置泵汽蚀余量计算取值的确定

给水泵和给水前置泵汽蚀余量计算中各项参数的取值将直接影响除氧器标高的确定，参考国内外工程实践经验．本文对计算中的参数选取提出了推荐意见。     

利用水喷射技术防止水泵的汽蚀

汽蚀现象是水泵应用的重大障碍。文章分析了离心式水泵汽蚀的机理,指出了解决水泵汽蚀问题必须提高入泵液态水所对应的饱和压力,即增大液态水的能量状态。介绍了利用喷射增压原理,在水泵入口加装水—水喷射器来解决水泵汽蚀的实用技术。利用该技术设计的密闭式凝结水回收系统,既成功地解决了汽蚀问题,又取得了显著的经济效益和节能、节水效益。     

汽动锅炉给水泵组盘车装置探讨

由于锅炉给水泵卡泵，盘车装置盘不动，而且盘车装置不能满足锅炉给水泵高速盘车的要求，国内不少电厂索性将盘车装置废弃不用了。卡泵问题与高速盘车问题是不是不能解决？汽动给水泵组是不是可以取消盘车装置？国内目前有没有一个完善解决汽动给水泵组盘装置的实例？本文将对以上问题进行探讨。     

运用新控制策略显著降低给水泵再循环阀汽蚀

为减少汽动给水泵再循环阀的汽蚀及降低汽动给水泵低负荷时的能耗。通过研究分析,采用全新的再循环阀控制策略,并在实际使用中进行验证。新的控制策略使汽动给水再循环阀在机组正常运行中保持全关,只有在汽动给水泵启动、停运过程中才需要开启,最大限度减少了再循环阀的汽蚀,并显著降低了汽动给水泵低负荷时的能耗。实践证明,所采用的新控制策略能够实现汽泵的节能降耗,延长再循环阀使用寿命,并保证汽动给水泵和锅炉给水流量的安全。     

带有诱导轮的变速给水泵性能试验研究

从降低除氧器设置高度和适应除氧器滑压运行出发,提出装置带有诱导轮的变速给水泵,以利降低泵组的必需汽蚀余量。经六个不同设计参量的诱导轮与100D16型多级离心泵的配合试验,结果表明:其中最佳的配合可使泵组必需汽蚀余量仅为原泵的1/5,效率较原泵提高6%,适应运行范围扩大了24.6%。     

工业回收冷凝水泵防汽蚀改造

在工业生产过程中，为了节能降耗，需要回收蒸汽冷凝水。由于冷凝水是饱和水，在用泵输送回用过程中易发生汽蚀，影响泵的安全稳定运行，有时不得不停止运行，就地排放冷凝水，这既损坏了设备，又浪费了能源。利用喷射增压的原理，可以解决泵的汽蚀问题。     

带有诱导轮的变速给水泵汽蚀性能测定

本文从降低除氧器设置高度和适应除氧器滑压运行出发.提出采用带有诱导轮的变速给水泵,以利降低泵组的必需汽蚀余量,经6个不同设计参量的诱导轮与100D16型多级离心泵的配合试验,测定结果表明:其中最佳的配合可使泵组必需汽蚀余量仅为原泵的1/5.效率较原泵提高6％,适应运行范围扩大了24.6％.     

凝结水回收器的研制与应用

长期以来，在凝结水回收系统中存在着两大难题，一是疏水阀质量不过关，二是给水泵被高温凝结水"汽蚀"破坏。根据本人在1982年以来的蒸汽供热工程设计中，因凝结水回收设施的简陋，形成大量宝贵凝结水排放，造成能源浪费和热污染状况，历经数年研制成功了"凝结水回收器"已获国家专利。在一批蒸汽锅炉上使用效果很好。现将原理及试验简述如下。1高位水箱不能防止水泵汽蚀破坏的原因多年来普遍认为高位水箱到水泵的垂直高差越大越好，高差大有利于水泵防止高温凝结水汽蚀破坏甚至将此写人规范。试验发现并非如此，静态时水头存在，泵动时静压…     

超超临界机组RB过程除氧器暂态特性计算模型

针对机组甩负荷时给水泵有效汽蚀余量下降、给水泵组可能发生汽蚀的问题,在试验基础上,通过对除氧器辅机故障减负荷(RB)暂态过程的理论分析,给出了超超临界机组除氧器暂态特性和给水泵最大有效汽蚀余量ΔNa,max的计算模型,并对试验数据和试验过程模拟结果进行了比较.结果表明:所用模型精度较高;降低除氧器水容积的波动幅度,或者在除氧器布置高度不变时减小下降管长度,均能减小ΔNa,max.     

基于BP神经网络与改进遗传算法的泵站优化调度

通常泵组件的调节主要依靠工程师经验,难以保证水泵在所有时段内均高效运行,易造成能源浪费,对此提出了以效率模型为依据的泵站优化调度方法。为减小误差,使用泵站实际运行数据基于BP神经网络训练水泵特性。在此基础上,利用训练后的数据初始化种群,以泵站效率之和最小为目标,建立泵站优化调度数学模型,设定水量、压力和高效区等约束条件,采用改进的遗传算法求解水泵组合方案及各泵运行参数。结果表明,改进遗传算法对泵站调度的优化效果明显,可适用于泵站的优化节能运行。研究成果为泵站优化调度运行提供了一种新方法。     

基于MIKE FLOOD的深圳市机场排涝泵站工程设计及运行模拟

为有效提升排涝泵站设计精度和操作适用性,以深圳市机场排涝泵站为例,基于MIKE FLOOD构建耦合了雨水管网、河道、泵站等工程设施的综合系统模型,对排涝泵站上游河道沿程水位的变化及排水需求进行模拟分析,并基于计算结果确定了泵站的设计规模及调度方式。结果表明,利用数学模型对排水系统进行适当概化和仿真模拟,基于设计降雨情景可对排涝泵站规模和运行规则进行精确地设计计算,可为城市排涝泵站工程设计提供技术借鉴。     

Review of mathematical investigation on the closed adsorption heat pump and cooling systems

A mathematical model of the closed adsorption heat pump and cooling systems is particularly used to assist in interpreting the observed phenomena, to design the system, to predict the trends, and to assist in optimization. In this paper, various mathematical models mainly analyzing the heat and mass transfer process of an adsorption bed in closed adsorption heat pump and cooling systems are reviewed and classified based on complexity, into three main groups: i.e. thermodynamic model; lumped parameters model; heat and mass transfer model. The major characteristics of different models and assumptions used are presented and discussed. Also, the numerical methods and validation of the models are summarized and significant results obtained through mathematical model are detailed. Although the models have evolved to a point where several features of the process can be predicted, more effort is required before the models can be applied to define actual operating conditions as well as to further investigate new closed adsorption cycles.     

基于R125工质热泵循环的理论分析

通过对热泵循环流程的分析,构建了带有回热器热泵的数理模型.理论分析了以R125为工质的热泵系统,并对R125及几种热泵工质在标准工况和变工况下的循环性能进行了系统的理论计算及分析.结果表明,在标准工况下,R125制热系数优于R22,是极有潜力的热泵替代工质.     

Theoretical analysis of the dynamic interactions of vapor compression heat pumps

A detailed mathematical model of vapor compression heat pumps is described. Model derivations of the various heat pump components are given. The component models include the condenser, evaporator, accumulator, expansion device, and compressor. Details of the modeling techniques are presented, as is the solution methodology. Preliminary simulation results are also illustrated. The model developed predicts the spatial values of temperature and enthalpy as functions of time for the two heat exchangers. The temperatures and enthalpies in the accumulator, compressor and expansion device are modeled in lumped-parameter fashion. Pressure responses are determined by using continuity satisfying models for both the condenser and evaporator. The discussion of the solution methodology describes the combined implicit/explicit integration formulation that is used to solve the governing equations. The summary provides a list of future work anticipated in the area of dynamic heat pump modeling.     

含沙水流条件下夹马口泵站水泵特性参数研究

为分析含沙水流条件下夹马口泵站的水泵特性参数,以泵站在含沙水流条件下的多组实测数据为基础,采用Matlab软件进行曲线拟合,得到含沙水流条件下水泵工作参数计算的新模型。对比分析表明,新模型的计算结果比陕西机械学院水泵实验室提出的模型的计算结果更接近实测数据,更适用于夹马口泵站的实际情况。根据新模型模拟计算出了不同含沙量对应的泵站效率,并提出了优化调度方案。研究成果可为夹马口引黄泵站运行调度提供指导,对其他引黄泵站的水泵特性研究也有一定借鉴作用。     

水泵转轮改型设计的数值计算

基于参考文献（２）,克服混合问题所特有的求解域内边界未定的难点,研究水泵转轮内部全三维不可压缩流体流动,提出三维流道改型设计数值模拟的新途径。     

某抽水蓄能电站首次泵工况启动关键因素的数值分析

根据某抽水蓄能电站实际水力布置情况,在分析其上库的实际充水特点和引水隧洞中明满流交替的水力特征的基础上,建立相应数学模型,采用特征隐式格式法求解有压管道非恒定流方程,优化了机组首次泵工况运行时的导叶开关规律及球阀关闭规律等关键因素,并利用优化后的关键因素对泵工况进行了大波动过渡过程计算,结果具有合理性。     

Numerical modeling of two-phase flows in the presence of dynamic and thermal interactions

The study of turbulent flow in mixtures consisting of gas and particulate matter is a current area of research among modern scientists. The main objective of this area is to prevent the reduction of burnout in flow-through systems. Therefore, the purpose of this research is to develop a mathematical model of turbulent gas flow with solids to explore the structure of the combustion region in a channel with a partially open boundary to determine the interfacial interaction of the injection of a flat heterogeneous flow in a confined area and the influence of regime parameters on the ignition process. For this purpose, a modeling method was used, which involved using the fundamental laws of continuity of flow, conservation of energy, and the quantity of motion and matter, and an experiment was conducted to reconcile the proposed model with theoretical data. As a result of this work, a model based on the averaged Reynolds Navier–Stokes equations and an algorithm for solving a turbulent subsonic two-dimensional flow in a heterogeneous medium based on an Euler–Lagrange representation have been developed. Thus, the effects of the parameters of entrainment, temperature, and component concentration on the combustion range and mixing intensity were determined. The proposed methodology can be applied to solve application problems of various kinds, for example, in the design of thermal power plants. The scope of the mathematical and numerical models developed is sufficiently broad that they are universal.     

复合热源热泵循环的节能研究

本文介绍了热泵空调的原理及主要特点，分析了单一空气热源热泵存在的缺陷，介绍了空气－水复合热源热泵循环的工作原理，提出了相应的数学物理模型，并对其制热性能进行分析。结论是空气－水复合热源热泵的制热性能明显优于单一空气热源热泵，具有较好的调节性和显著的节能性。