用焓熵公式计算水泵效率

水泵效率试验的方法有两种,传统的方法是Q—H法,通过测量泵流量,扬程及轴功率来计算水泵效率。另一种是热力学法,又称微温差法,是基于热力学原理,通过测量水泵进出口处流体的热力学参数(温度、压力)未确定水泵的效率。     

热力学法真机效率测定

<正> 1 引言采用热力学法测定水轮机或水泵水轮机的效率时,只需测量水轮机或水泵水轮机进水断面和出水断面的水压和水温,就可以求出其效率。除热力学法外,其他各种效率测定     

用焓差法测算给水泵内效率

本文运用热力学原理,较简便地导出了用焓差和压差求取水泵内效率的计算式。提出了通过监测水泵内效率状态,来确定水泵检修日期的设想,并列举了应用实例。     

微温差法泵特性测试的精度及其影响因素

在泵的特性试验中,一种应用热力学原理,仅需测量泵的进、出口压力及温度差就能测出泵效率的方法——微温差法泵特性测试,已引起了大家极大的关注。因其最大的优点是:无需测量水泵的流量,因而也不要求为测量流量所必须具备足够长的直管段和测量装置(孔板、比托管、容积池等),使原来无条件测量泵效率的测试变为可能。这样,可通过普查,测得泵的实际运行效率,以达到经济运行。关于这种测试技术的理论推导及方法可参见资料。本文只着重回答大家更为关心的问     

水泵综合性能试验台校准方法的研究

为了保证水泵性能测试结果的准确性和可靠性,本文介绍了水泵综合性能试验台需要校准的项目以及方法,给出了试验台测量结果不确定度评定的计算方法。最后就水泵综合性能试验常见的试验项目,列举了具体的计算方法。     

泵段、水泵模型测试段与泵段效率修正

根据低扬程大型泵站泵装置出水流道的水力设计要求,修正了＂泵段＂的定义,计算了水泵模型测试段中进出水管道的水力损失,并对＂泵段＂效率进行了修正;根据修正后的＂泵段＂效率对南水北调东线工程3个泵站设计工况的＂泵段效率＂、流道效率和泵装置效率之间的关系进行了验证性计算。研究结果表明：＂泵段＂宜定义为由水泵叶轮和导叶体这两个最基本的过流部件组成;南水北调工程水泵模型同台测试提供的水泵模型综合特性曲线表达的是水泵模型测试段的水力性能,其中包含了测试段中进水管道和出水管道的水力损失;大型泵站泵装置中的＂泵段＂性能应在水泵模型测试段水力性能的基础上考虑进出水管道水力损失进行修正;由水泵模型测试段性能修正得到的＂泵段＂扬程和效率均较水泵模型测试段高,设计流量时的扬程修正值约为0.15m左右;效率修正值与水泵模型测试段扬程有关,水泵模型测试段扬程愈低,修正值愈大,其幅度约为（1～4）%。流道效率根据流道水力损失及泵装置扬程计算得到,根据流道效率和修正后的＂泵段＂效率对设计工况的泵装置效率进行预测,其结果与泵装置模型试验得到的结果相比小于1%。     

确定模型水泵水轮机水泵工况叶片初生空化的声学方法研究

目前,模型水泵水轮机水泵工况下转轮叶片压力面的初生空化的判断,还停留在人工甄别的阶段,导致判断结果因人而异.本文提出一种声学方法来判断水泵工况下模型水泵水轮机转轮叶片初生空化的发生.利用基于水听器的测试系统,提取并分析空化噪声的特征量来判断初生空化何时发生.通过实验验证了该方法的合理性和准确性,因此,该方法对模型水泵水...     

电厂辅机轴承振动故障诊断分析

针对某厂一台离心式水泵振动大的问题,通过振动测试分析,诊断出轴承滚动体故障是引起水泵振动大的原因,依据诊断结论给出更换轴承的检修建议,更换轴承后,水泵振动故障消失。结果表明,该水泵的振动特征及处理过程具有代表性。给出分析、诊断的思路和处理方法,可以为类似的辅机振动诊断和处理提供参考。     

凝结水泵运行中出力降低故障树诊断方法研究

凝结水泵是火电机组的重要动力设备,如运行中出力降低,会直接威胁机组的安全运行。采用故障树诊断方法,从汽蚀、气缚、机械故障等方面,列出凝结水泵出力降低的各种故障象征,建立故障诊断模型。结合2台300 MW机组运行中凝结水泵出力降低案例进行测试验证,找到出力降低的原因,检修后恢复正常。     

大中型立式电机水泵效率特性的现场测试方法

文章论述了在现场条件下 ,完全符合国家标准地完成电机水泵的效率测试的方法。详细地介绍了电机的各种损耗和测试原理。对测试结果的误差进行了分析     

具有CO2负排放的风电高温储能系统模拟

风能的反调峰特性使得弃风现象较为严重。针对该情况,提出了CaO高温储能耦合生物质发电厂消纳风电的方法,有望实现风电的规模化储存和CO2负排放,并构建了CaO储能耦合生物质发电并捕集CO2的系统模型;此外,基于Aspen Plus软件平台对系统的热力性能进行了模拟,分析了碳酸化炉接入位置对系统储电效率和CO2捕集量的影响。同时,结合对碳酸化炉和CaCO3煅烧炉的灵敏度分析,得到了最佳工作条件下的集成系统储电效率和消纳单位风电的CO2捕集量。     

火电厂管道热效率及行业标准的探讨

阐述了火电厂管道热效率的热力系范围及其热损失 ,用理论分析和实例计算 ,初步指出了现有管道热效率行业标准的不合理性及其原因 ,对电厂热力系统节能提出了积极的建议。     

一种基于系统结构特征矩阵的火电厂热力系统通用矩阵模型

提出了一种火电厂热力系统通用矩阵模型，该模型基于热力系统的组态结构矩阵，全面考虑了回热加热器换热效率以及各种辅助汽水等因素，以矩阵论为基础，对回热加热器的物质平衡和能量平衡关系进行了分析，通用性很强。该模型适用于不同类型或同类型、不同热力系统的大型火电机组的热经济性分析，为热力系统的实时监测、控制和优化提供了方便的工具。     

Layouts of trigeneration plants for centralized power supply

One of the possible and, under certain conditions, sufficiently effective methods for reducing consumption of fuel and energy resources is the development of plants for combined generation of different kinds of energy. In the power industry of Russia, the facilities have become widespread in which the cogeneration technology, i.e., simultaneous generation of electric energy and heat, is implemented. Such facilities can use different plants, viz., gas- and steam-turbine plants and gas-reciprocating units. Cogeneration power supply can be further developed by simultaneously supplying the users not only with electricity and heat but also with cold. Such a technology is referred to as trigeneration. To produce electricity and heat, trigeneration plants can use the same facilities that are used in cogeneration, namely, gas-turbine plants, steam-turbine plants, and gas-reciprocating units. Cold can be produced in trigeneration plants using thermotransformers of various kinds, such as vaporcompression thermotransformers, air thermotransformers, and absorption thermotransformers, that operate as chilling machines. The thermotransformers can also be used in the trigeneration plants to generate heat. The main advantage of trigeneration plants based on gas-turbine plants or gas-reciprocating units over cogeneration plants is the increased thermodynamic power supply efficiency owing to utilization of the waste-gas heat not only in winter but also in summer. In the steam-turbine-based trigeneration plants equipped with absorption thermotransformers, the enhancement of the thermodynamic power supply efficiency is determined by the increase in the heat extraction load during the nonheating season. The article presents calculated results that demonstrate higher thermodynamic efficiency of a gas-turbine-based plant with an absorption thermotransformer that operates in the trigeneration mode compared with a cogeneration gas-turbine plant. The structural arrangements of trigeneration plants designed to supply electricity, heat, and cold to the users are shown and the principles of their operation are described. The article presents results of qualitative analysis of different engineering solutions applied to select one combination of power- and heat-generating equipment and thermotransformers or another.     

On the possibility of generation of cold and additional electric energy at thermal power stations

A layout of a cogeneration plant for centralized supply of the users with electricity and cold (ECCG plant) is presented. The basic components of the plant are an expander-generator unit (EGU) and a vapor-compression thermotransformer (VCTT). At the natural-gas-pressure-reducing stations, viz., gas-distribution stations and gas-control units, the plant is connected in parallel to a throttler and replaces the latter completely or partially. The plant operates using only the energy of the natural gas flow without burning the gas; therefore, it can be classified as a fuelless installation. The authors compare the thermodynamic efficiencies of a centralized cold supply system based on the proposed plant integrated into the thermal power station scheme and a decentralized cold supply system in which the cold is generated by electrically driven vapor-compression thermotransformers installed on the user’s premises. To perform comparative analysis, the exergy efficiency was taken as the criterion since in one of the systems under investigation the electricity and the cold are generated, which are energies of different kinds. It is shown that the thermodynamic efficiency of the power supply using the proposed plant proves to be higher within the entire range of the parameters under consideration. The article presents the results of investigating the impact of the gas heating temperature upstream from the expander on the electric power of the plant, its total cooling capacity, and the cooling capacities of the heat exchangers installed downstream from the EGU and the evaporator of the VCTT. The results of calculations are discussed that show that the cold generated at the gas-control unit of a powerful thermal power station can be used for the centralized supply of the cold to the ventilation and conditioning systems of both the buildings of the power station and the neighboring dwelling houses, schools, and public facilities during the summer season.     

凝汽式汽轮机相对内效率在线监测的一种近似计算方法

针对汽轮机热力试验条件与正常运行条件间的差别 ,指出正常运行中汽轮机并不具备热力试验所要求的完全隔离的条件 ,同一电厂中各机组间总有一定的汽 (水 )联系。因此 ,对于正常运行的汽轮机 ,无法采用常规热力试验所采用基金项目 :国家电力公司重点科技资助项目 (SPKJ0 13 0 7)。的求解汽轮机质量和能量平衡方程的方法在线求解排汽焓 ,从而使在线准确确定汽轮机相对内效率存在一定的困难。文中提出一种在线计算汽轮机相对内效率的热力学近似方法 ,该方法基于汽轮机热力循环的基本原理 ,采用一些容易测量的参数来推算汽轮机的相对内效率 ,避开了常规的求解排汽焓的难题。通过与汽轮机热力试验结果的比较 ,证明该方法足以满足工程上对计算精度的要求。最后给出该方法在某 10 0MW汽轮机相对内效率在线监测中的应用情况。     

Organic Fuel Synthesis from Atmospheric Carbon Dioxide and Hydrogen Produced from Water by Electrolysis

Synthesis of organic fuels from cain dioxide and hydrogen is analysed, in terms of energy recovery efficiency, and the required energy input for electrolysis of water. This electrical energy is related to the thermal energy required in a power station. A method is described to recover heat from energy-producing reactions in the fuel synthesis process, which can then be used to reduce the electrical energy requirement for electrolysis. By co-locating the fuel synthesis plant with a thermal power station, primary (thermal) energy can be used to produce high temperature steam, with a lower electrical requirement for electrolytic production of hydrogen. This can make more efficient use of the primary energy than a thermodynamic engine. Comparison is made with alternative fuels, in terms of energy budget, sustainability, carbon dioxide emissions, etc. The energy security benefits of advanced fuel synthesis are also identified.     

基于汽轮机变工况理论的运行初压确定

大容量热力发电机组的调峰运行及热力系统的变工况分析计算一直是热能动力工程领域的研究课题.当火电机组运行远离设计工况时,分析系统的热经济性并给出恰当的运行指导在工程实践中有着十分重要的意义.该文以汽轮机变工况理论为基础,深入揭示了火电机组变负荷工况下的内在特性变化规律,从系统工程的观点出发,根据热力系统拓扑结构及其热力学...     

利用低温省煤器吸纳弃风电量研究

为了解决我国冬季弃风严重的问题,提出了一种利用低温省煤器原有热力系统来吸纳弃风电量的方法,该方法建设成本低、维护简单、效率高且不会对环境造成污染。通过对江苏南热发电有限责任公司1号机组试验分析可知,该方法可以最大限度降低机组能耗,避免由于气候原因造成资源浪费,能够吸纳的弃风电量非常可观。     

智能电网推动发电厂节能减排的策略研究

提高发电环节的能源效率是全面推进“坚强智能电网”发展规划的必要环节,提高发电厂的能源效率,是每个发电企业应遵守的起码道德标准和基本社会责任,也是实现企业经济效益的必由之路.分析了智能电网背景下发电厂的节能技术,包括电动机节能技术、照明节能技术、空调和热水的节能减排技术等.在智能电网方案下,通过环境监测与评估,应用传感器...