汽轮机转子热应力计算控制（ABB TURBOMAX）系统介绍

汽轮机启停或变负荷过程中,均会使汽轮机转子产生热应力。本文介绍了一种基于温差控制的汽轮机转子热应力应用。重点分析了其热应力计算模型及计算方法。实际使用情况表明,此种热应力计算方法科学有效,在不增加汽轮机转子寿命损耗的前提下,可明显地缩短机组启动时间。     

汽温非线性变化时汽轮机转子的热应力

汽轮机启动时,汽温变化通常是非线性的;本文对汽轮机实际启动时转子热应力的变化规律进行了分析与计算,提出了汽轮机实际启动过程转子热应力的简化计算方法.     

S109 FA燃气-蒸汽联合循环中汽轮机的热应力分析与控制

介绍了汽轮机热应力的形成和计算方法。对启动过程中产生的转子热应力进行了分析,从温度匹配、进汽方法、控制蒸汽品质等方面阐述了GE公司S109FA联合循环中汽轮机转子热应力控制方法。     

汽轮机强制冷却过程空气温度的选择

以６００ＭＷ汽轮机高压转子为对象，以有限元法的手段，通过滑渗数停机及其后的自然冷却过程的计算得到强制冷却初始温度场，在几种典型的空气温度分段曲线下计算出高压转子热应力，为强制冷却实验设计提供依据。介绍计算模型的选取、网络的划分及边界条件的确定。     

汽轮机转子在有热冲击情况下实现等热应力启动的研究

根据汽轮机转子在启动过程中的热应力形成机理 ,将汽轮机转子简化为无限长空心圆柱体模型 ,根据热传导理论 ,推导出在有热冲击情况下 ,保持汽轮机转子热应力不变的条件 ;并运用有限元法计算了捷制2 0 0MW机组温态启动工况下实现等热应力启动的情况 ,从而验证了该条件的正确性。图 7参 3     

考虑变物性的超临界汽机转子热应力计算与分析

汽轮机转子材料的物理特性随温度变化显著,而其物性参数的变化会直接影响到热应力的计算结果。在汽轮机转子的热应力计算模型中充分考虑了转子材料的物性随温度变化的影响,并通过对某国产600 MW超临界汽轮机转子的冷态启动仿真试验,得出了其热应力的变化曲线,并与常物性下的结果进行了对比和分析,以期为准确掌握机组转子的热应力水平提供参考。     

引进型330 MW机组转子温度场在线计算

汽轮机转子热应力的变化取决于转子金属温度场的变化。提出了一种离散化且易于编程实现的温度场数学解析方法，实现汽轮机转子温度场的实时在线计算，更准确地再现机组在实际启停过程中转子最大热应力区段内的温度变化规律，实际应用效果证明该方法是有效的。     

国产200兆瓦中间再热机组转子的热应力及疲劳寿命

本文分析了国产200兆瓦中间再热汽轮机转子在启停和负荷变动时的过渡工况热应力和低周疲劳损耗问题。给出并分析了高中压转于进汽区在不同温升率下启动时的金属温差及转子表面热应力随时间的变化规律。在结论中提出了降低汽轮机转子热应力应该采取的措施。本文提出的转子温差及热应力的简化计算方法,也适用于其他同类型的机组。     

关于国产30万千瓦汽轮机的热应力问题

我国自50年代以来,大型汽轮机不断发展完善。60年代在处理汽缸热应力方面取得了成绩;70年代以来,在处理汽轮机热膨胀与转子热应力方面积累了一定的经验。现代大型汽轮机通常都根据热应力(特别是转子热应力)开车。只要热应力方面无问题,一般在热膨胀、热变形与振动等方面也就没有什么大问题了。一、现代大型汽轮机热应力方面的主要特点 1.金属材料的强度裕量,比中小型汽轮机小得多,其主要原因为:     

汽轮机转子热应力监控

汽轮机转子热应力监控是转子寿命管理的一个重要内容,本文介绍了汽轮机转子加热过程中动态传热的一维数学模型及拉氏变换后的温度和应力解,对一种典型的汽轮机转子热应力实时监控系统进行了简单分析。     

直接空冷排汽管道系统内湿蒸汽的数值模拟

建立了某台135MW发电机组直接空冷排汽管道内湿蒸汽两相流动和传热的数学模型。利用计算流体动力学(CFD)软件,对典型工况下汽轮机的排汽状况进行了数值模拟,所得结果可为空冷排汽管道系统的优化设计提供帮助。     

1 000 MW 直接空冷凝汽器变工况研究

以1 000 MW直接空冷机组为例,基于效能—传热单元数方法,建立了直接空冷机组凝汽器变工况数学模型。通过分析排汽管道压降及机组对环境散热量等因素对汽轮机末级排汽压力的影响,得出汽轮机末级排汽压力与环境温度、迎面风速、排汽流量间的关系曲线。分析了汽轮机末级排汽压力与其影响因素之间的线性关系,为1 000 MW空冷机组在变工况下选择合适的排汽压力和提高经济性提供参考。     

Combined cycle plants: Yesterday,today, and tomorrow (review)

Gas turbine plants (GTP) for a long time have been developed by means of increasing the initial gas temperature and improvement of the turbo-machines aerodynamics and the efficiency of the critical components air cooling within the framework of a simple thermodynamic cycle. The application of watercooling systems that were used in experimental turbines and studied approximately 50 years ago revealed the fundamental difficulties that prevented the practical implementation of such systems in the industrial GTPs. The steam cooling researches have developed more substantially. The 300 MW power GTPs with a closedloop steam cooling, connected in parallel with the intermediate steam heating line in the steam cycle of the combined cycle plant (CCP) have been built, tested, and put into operation. The designs and cycle arrangements of such GTPs and entire combined cycle steam plants have become substantially more complicated without significant economic benefits. As a result, the steam cooling of gas turbines has not become widespread. The cycles—complicated by the intermediate air cooling under compression and reheat of the combustion products under expansion and their heat recovery to raise the combustion chamber entry temperature of the air—were used, in particular, in the domestic power GTPs with a moderate (700–800°C) initial gas turbine entry temperature. At the temperatures being reached to date (1300–1450°C), only one company, Alstom, applies in their 240–300 MW GTPs the recycled fuel cycle under expansion of gases in the turbine. Although these GTPs are reliable, there are no significant advantages in terms of their economy. To make a forecast of the further improvement of power GTPs, a brief review and assessment of the water cooling and steam cooling of hot components and complication of the GTP cycle by the recycling of fuel under expansion of gases in the turbine has been made. It is quite likely in the long term to reach the efficiency for the traditional GTPs of approximately 43% and 63% for PGUs at the initial gas temperature of 1600°C and less likely to increase the efficiency of these plants up to 45% and 65% by increasing the gas temperature up to 1700°C or by application of the steam cooling in the recycled fuel cycle.     

660 MW机组汽轮机真空快速冷却系统的应用

通过对邯峰发电公司660 MW机组汽轮机的结构分析,介绍了其采用的真空法快速冷却(快冷)系统,并将真空法快冷与常用的加热压缩空气法快冷进行了比较。实践证明,真空快冷系统的应用较为安全可靠。     

600 MW机组直接空冷排汽管道系统内流场的数值模拟

利用计算流体力学(CFD)软件对大同第二发电厂600MW发电机组直接空冷排汽管道内的水蒸气流场进行了数值模拟,并对模拟结果进行了简要分析,可为直接空冷排汽管道系统的优化设计提供帮助。     

350 MW机组汽轮机强制冷却分析

介绍了沙角B电厂汽轮机在计划性检修停机过程中,利用蒸汽强制冷却和停机后再用压缩空气冷却的方法和过程。蒸汽强制冷却和压缩空气冷却方法的结合使用,大大减少了停机后汽轮机的冷却时间,为缩短机组检修工期创造了有利条件。     

Steam Condensation from a Moving Steam-Gas Mixture

To date, heat exchange has been studied to the greatest extent for the case of the condensation of pure still and moving steam as well as for the case of condensation from a still steam-gas mixture. There are hardly any papers available wherein a moving steam-gas mixture with a substantial content of noncondensable gases is considered. To investigate this process, an experimental workbench of the working section has been developed, which makes it possible to determine the local values of the heat transfer coefficient from the steam-gas mixture to the walls of cooled heat-exchange tubes at different parameters and velocities of the gas-steam mixture. In the first four rows of tubes of the working section, there is no cooling, and their function consists in a hydraulic stabilization of the flow. In the fifth and the sixth row of tubes, the wall temperature of the cooled heat-exchange tubes is measured for determining the heat transfer coefficients from the moving steam to the tube walls. The seventh row of tubes is also not under cooling. Measuring tubes with temperature sensors have been manufactured that make it possible to obtain the wall temperature for determining the heat transfer coefficient. The adopted scheme of steam motion and the measurement system make it possible to obtain correct results of the heat and mass transfer investigation in the course of steam condensation from a gas-steam mixture with a significant content of noncondensing gases. The studies on steam condensation from a moving steam-gas mixture have been carried out in the range of parameter ρw² = 9.5 ? 66 Pa and at a volume concentration of air in the steam amounting up to ν_air = 0.18. Convective heat transfer coefficient α values for the heat transfer from a moving steam-gas mixture to the wall of a cooling tube were obtained. At small values of parameter ρw² = 9.5 Pa and the volume fraction of the air content ν_air = 0.06 in the steam, the average heat transfer coefficient exhibits a decrease by a factor of two as compared with that inherent in the condensation of almost pure steam. At the values of parameter ρw² = 66 Pa and at ν_air = 0.06, the average heat transfer coefficient decreases by 1.3 times. The studies on almost pure steam are in good agreement with Berman’s dependence.     

Thermal gain of CHP steam generator plants and heat supply systems

Heating calculation of the surface condensate heat recovery unit (HRU) installed behind the BKZ-420-140 NGM boiler resulting in determination of HRU heat output according to fire gas value parameters at the heat recovery unit inlet and its outlet, heated water quantity, combustion efficiency per boiler as a result of installation of HRU, and steam condensate discharge from combustion products at its cooling below condensing point and HRU heat exchange area has been performed. Inspection results of Samara CHP BKZ-420-140 NGM power boilers and field tests of the surface condensate heat recovery unit (HRU) made on the bimetal calorifier base КСк-4-11 (KSk-4-11) installed behind station no. 2 Ulyanovsk CHP-3 DE-10-14 GM boiler were the basis of calculation. Integration of the surface condensation heat recovery unit behind a steam boiler rendered it possible to increase combustion efficiency and simultaneously decrease nitrogen oxide content in exit gases. Influence of the blowing air moisture content, the excess-air coefficient in exit gases, and exit gases temperature at the HRU outlet on steam condensate amount discharge from combustion products at its cooling below condensing point has been analyzed. The steam condensate from HRU gases is offered as heat system make-up water after degasification. The cost-effectiveness analysis of HRU installation behind the Samara CHP BKZ-420-140 NGM steam boiler with consideration of heat energy and chemically purified water economy has been performed. Calculation data for boilers with different heat output has been generalized.     

燃气电厂机力通风冷却塔的运行方式及优化

结合国内某燃气电厂循环水冷却系统的特点,分析了该类型机组最佳真空度的不确定性,以现场实际运行数据为基础,试验论证了获得汽轮机运行极限真空度的可行性,由此优化了机力通风冷却塔的运行方式,并收到良好的节能效果。     

汽轮机空气快冷系统的改进

现代大型汽轮机为缩短检修工期,尤其是汽轮机故障处理时,常采用空气快冷的方法来缩短汽轮机的冷却时间。通过对汽轮机快冷系统的分析,针对所存在的问题提出了对快冷系统的改进措施。改进后的快冷系统比现在使用的系统更简单、经济,并对改进系统应用的可行性举例分析。