超超临界汽轮机补汽结构流动特性与损失分布EI北大核心CSCD

针对超超临界汽轮机补汽装置内复杂流动和效率低下的问题,采用计算流体力学软件CFX建立高压缸两级补汽流动模型,分析补汽装置的性能与损失。对比4种补汽结构内流场的流动特性、气动特性以及流动损失分布,揭示补汽结构流动特性和损失机理,得到性能较好的补汽结构。结果表明:补汽过程中腔室内始终存在位置、大小不同的涡流。中间进汽弯小管的压力分布较为均匀,总压损失较小,腔室内的粘性损失也最小。侧边进汽弯小管的管内粘性损失最小,中间进汽弯小管的管内粘性损失小于中间进汽直小管。中间进汽弯小管的流动效率较好,补汽结构的总体损失较小。     

330MW汽轮机叶顶汽封间隙优化及经济性分析

北方联合电力有限责任公司达拉特发电厂2号、4号、5号汽轮机组经多年运行后,汽轮机缸内漏汽损失大、汽缸效率下降、热耗率高。通过对间隙超标的高、中压缸叶顶汽封阻汽片进行更换,优化叶顶汽封设计间隙等工作,高、中压缸效率效率分别提高3%和2.3%,热耗率平均降低约80 kJ/kWh,机组经济性得到提高。     

超临界600MW机组汽封改造分析

针对超临界600 MW凝汽式汽轮机组,高、中、低压缸效率均比设计值低,高、中压缸平衡盘漏汽率比设计值高等热耗率偏高的现状,在机组A级检修期间对汽封进行了改造,高压缸采用布莱登汽封,低压缸采用蜂窝汽封,高中压缸叶顶阻汽片更换调整。修后性能试验高、中、低压缸效率分别提高了1.1%、3.25%、0.38%,热耗率降低了133.40 kJ/（kW.h）,提高了机组的经济效益。     

刷式汽封在引进型300MW汽轮机上的应用

针对白山热电有限责任公司2号机组存在系统内漏、汽轮机的各级汽封间隙超标、汽轮机的级间泄漏量大、汽缸效率偏低等问题,为了减少高、中压缸级间漏汽量,提高各缸的效率及低压缸的真空,在2号机组大修中进行刷式汽封改造。改造后在五阀全开工况下,汽轮机的高压缸效率由81.47%提高到83.28%,提高了1.81%;中压缸平衡盘漏汽情况达到了较好水平;凝汽器真空度得到了提高。     

200MW汽轮机中压缸启动轴向推力的控制

长山热电厂9号机为哈尔滨汽轮机厂制造的N200—130/535/535型中间再热式汽轮机,配有30%额定流量的两级串联旁路系统。自1988年10月投产以来,采用常规的高、中压缸联合启动。存在的主要问题是汽轮机冷态启动中,中压缸膨胀不畅,再热汽温滞后于主汽温度及启动时间长等。为解决上述问题,提高汽轮机启动安全性和经济性,我厂采用中压缸启动来代替高、中压缸联合启动,收到较好的效果。但采用中压缸启动的突出问题是汽轮机高压缸不进汽,只中、低压缸进汽,使整个转子轴向推力随中压缸进汽量的增加而增大.且主要由推力     

高中压缸合缸机组中轴封漏汽率试验的参数敏感性分析

高中压缸合缸机组中对中轴封漏汽率须采用单独的变温度试验确定。影响中轴封漏汽率试验结果的主要参数包括高压调节级参数、中压缸进汽调节阀压损、中压缸进汽参数及排汽参数。以某600 MW超临界机组为例,对各项测量参数的测量偏差对中轴封漏汽率试验结果的影响进行了计算。计算结果表明,热再温度、中压缸排汽压力、及中压缸排汽温度对漏汽率试验结果的影响最大,而其它参数的测量偏差则对试验结果的影响较小,试验中应尽量采取针对性措施来改进热再温度、中压缸排汽压力、及中压缸排汽温度的测量准确性。     

东方超超临界二次再热660 MW汽轮机超高压进汽蜗壳数值研究

本文采用CFD数值分析软件完成了东方新开发的超超临界二次再热660 MW汽轮机超高压进汽蜗壳的气动性能分析,分析对象包括进汽蜗壳截面的收缩比、截面形状以及进汽管横向间距,结果表明该机组采用的切向进汽方式具有优越的气动特性,其进汽蜗壳截面收缩比、截面形状以及进汽管横向间距均对切向进汽室的气动特性有较大影响,湍动能和总压损失系数随截面收缩比的增加逐渐减小并趋于平缓,截面形状和进汽管横向间距对切向进汽室总压损失系数影响较小,但对出口处湍动能影响较大。     

某超临界600MW可调整式双抽供热机组供热经济性分析

600 MW超临界双抽供热机组是国内首台600 MW可调整式双抽供热机组,没有成熟的经验和案例,中压调门参与调整节流保证中压供热压力,中压缸排汽碟阀节流保证低压供热压力,直接影响中压缸效率,负荷越低、供热流量越大节流损失越大,对经济性影响越大。文中重点分析了中压供热对机组经济性的影响。     

汽轮机汽封改造对经济指标和振动影响的测试分析

介绍了汽轮机梳齿汽封的密封原理和缺陷,以及刷式汽封、柔齿汽封两种新型汽封的工作原理、优点和在汽轮机轴系、通流部分中适合的部位。刷式汽封在汽轮机上的应用比较广泛,高、中、低压缸各部位均适合;柔齿汽封主要应用于轴端密封。由于这两种型式汽封密封间隙小,在汽轮机汽封改造中得到比较广泛应用。145 MW机组采用柔齿汽封改造后,满负荷工况下,机组高压缸效率提高3.77%,中压缸效率提高2.65%,热耗率降低321.2 kJ/kWh;220 MW机组采用刷式汽封改造后,满负荷工况下,机组高压缸效率提高2.23%,中压缸效率提高0.56%,热耗率降低290.44 kJ/kWh;330 MW机组采用柔齿汽封和刷式汽封相结合的改造方案后,满负荷工况下,热耗率降低265.84 kJ/kWh。     

低压缸零出力改造对配备碳捕集燃煤电站灵活性提升作用分析

为研究脱碳对火电机组的影响，建立仿真模型分析了火电机组碳捕集改造常规方案的性能变化，进一步提出了低压缸零出力方案提升机组灵活性。常规方案以中压缸排汽为再沸器热源，低压缸零出力方案切断低压缸进汽。一方面，以300 MW燃煤电站为例，分别对2种方案进行分析；另一方面，以西北某省为研究对象，预测2种方案对全省火电的影响。结果表明：常规方案下机组出力空间由87～300 MW缩减至147～217 MW，额定工况的供电效率由37.32%下降至27.02%，机组最小负荷率约升高至70%；采用低压缸零出力方案时，机组负荷空间被拓宽到47～217 MW，为常规方案的2.44倍；对于所讨论的西北省份而言，常规方案下全省火电出力空间由1 103～3 940 MW缩减至1 875～2 793 MW，低压缸零出力方案下，出力空间被拓宽为550～2 793 MW。     

Performance analysis of closed loop in a CCMHD single power generation system

Results of numerical study on performance of closed loop in the CCMHD single power generation system are presented. The small closed loop with thermal input of 2.3 MW was designed. The fluid‐dynamical and thermal performance of the closed loop was calculated for the first time by one‐dimensional numerical simulation. The result indicates that pressure loss and heat loss are large in the designed small closed loop. The large pressure loss was due to the wall friction or the pebble bed and it occurred at the supersonic nozzle, the MHD channel, and the regenerative heat exchanger used for argon cooling. The enthalpy extraction remained low (= 17.6%) owing to the large pressure loss and as a result, the thermal efficiency of the closed loop remained only 21.6%. The enthalpy extraction and the thermal efficiency became maximal at the optimal inlet total pressure of 0.60 MPa. At inlet total pressure lower than the optimal one, the electric conductivity, the flow velocity, and the electric efficiency became higher. However, the total pressure ratio (= exit/inlet) in the MHD channel became larger particularly at low inlet total pressure because of the increase in the pressure loss due to pebble bed and wall friction. These led to the existence of the optimal inlet total pressure. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(1): 27–38, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10118     

一种进气道畸变测量动态压力采集设计

在新机型发动机科目试飞中,发动机进气道畸变特性测试至关重要,其稳定性关系到发动机能否可靠工作。传统方式中将多路进气道壁面总压进行采集,通过后期数据解析提取总压中的动态分量进行分析,此方式延迟较大且提取精度较低。因此设计了一种进气道畸变动态分量实时测量提取方案,在传感器最前端将进气道壁面总压信号中的动态分量进行分离、高增益及滤波处理后采集,与总压信号处于同步状态,保证数据实时相关性,以便评测对比,为发动机进气道畸变量测试提供新的思路。经试验与试飞测试验证,动态压力数据采集精度高达0.3%,满足试飞测试要求,目前已成功应用于某机进气道畸变试飞中。     

多喷孔活塞式调流调压阀空化流动特性分析

以DN200多喷孔活塞式调流调压阀为研究对象,基于数值模拟,结合Realizable k-ε湍流模型和Zwart-Gerber-Belamri空化模型,研究了小开度、中等开度和大开度下空化流动特性以及节流孔内空化的形成机制,并且分析了开度和空化数对空化流动的影响。结果表明,节流孔处存在较大的压力和流速梯度,节流孔进口边缘附近会出现流动分离,在节流孔壁面形成附壁剪切旋涡,流动分离和附壁剪切旋涡是节流孔内空化的形成机制。同时,固定阀门进出口压力,随着开度逐渐增大,空泡体积线性增加,各开度空化强度相差不大。另外,随着空化数逐渐减小,流量系数呈现出先保持稳定后略微增加再急剧减小的变化趋势。本研究结果可以为该类型阀门的结构优化与运行维护提供参考。     

混流式水轮机转轮进出口流场微机检测系统研究

本文研制的微机检测系统用于转轮进出口流场测量,系统采用5孔探针为感应元件,全部数据处理及计算都由计算机完成。最后输出测点的全速度、分速度、全压、静压、水流转角及水流斜角,并用绘图仪绘制出各参数沿径向变化的曲线。叙述了系统的构成、基本原理、软件编制、误差处理,并给出了实测数据曲线,结果完全满足精度要求。该系统还可用于其他叶轮机进出口流场测量。     

Problems in creation of modern air inlet filters of power gas turbine plants in Russia and methods of their solving

The main problems in creation and operation of modern air inlet paths of gas turbine plants installed as part of combined-cycle plants in Russia are presented. It is noted that design features of air inlet filters shall be formed at the stage of the technical assignment not only considering the requirements of gas turbine plant manufacturer but also climatic conditions, local atmospheric air dustiness, and a number of other factors. The recommendations on completing of filtration system for air inlet filter of power gas turbine plants depending on the facility location are given, specific defects in design and experience in operation of imported air inlet paths are analyzed, and influence of cycle air preparation quality for gas turbine plant on value of operating expenses and cost of repair works is noted. Air treatment equipment of various manufacturers, influence of aerodynamic characteristics on operation of air inlet filters, features of filtration system operation, anti-icing system, weather canopies, and other elements of air inlet paths are considered. It is shown that nonuniformity of air flow velocity fields in clean air chamber has a negative effect on capacity and aerodynamic resistance of air inlet filter. Besides, the necessity in installation of a sufficient number of differential pressure transmitters allowing controlling state of each treatment stage not being limited to one measurement of total differential pressure in the filtration system is noted in the article. According to the results of the analysis trends and methods for modernization of available equipment for air inlet path, the importance of creation and implementation of new technologies for manufacturing of filtering elements on sites of Russia within the limits of import substitution are given, and measures on reliability improvement and energy efficiency for air inlet filter are considered.     

Improvement of performance of disk MHD generator with argon by introduction of swirl

An experimental study of performance of the disk MHD generator with argon was carried out using a shock‐tube driven facility. An inlet swirl was introduced in the MHD channel in order to improve the enthalpy extraction and the isentropic efficiency. The experimental results were compared with those of the disk MHD generator without the inlet swirl. A high enthalpy extraction of 25.7% was obtained and the highest isentropic efficiency for argon was achieved at the same time in the present experiment. The measured static pressure in the MHD channel was kept lower than that without the inlet swirl. This has suggested that the introduction of the inlet swirl reduces the retarding force for the flow and that the increase of the enthalpy extraction is ascribed to the increase of the flow velocity and of the electrical efficiency. Furthermore, the flow without shock wave was observed at low seed fractions and low load resistances. At the same time, it was found for the first time that when there was no shock wave, the isentropic efficiency became higher than that with the shock wave. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(1): 18–25, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10045     

LED模块用液冷基板的流道和换热性能研究

针对大功率LED模块用液冷基板,通过理论分析,提出中间入口的S型流道、双S型流道和中间入口的双S型流道3种改进流道结构,并进行数值模拟。模拟结果表明,在相同的入口流速（流量）和入口水温下,中间入口的S型流道具有最佳的流动和换热综合性能;双S型流道性能次之;中间入口的双S型流道压降最小、且随入口流速增长缓慢,具有最佳的流动性能,提高流量时其散热性能可得到显著改善,因而流量可变时,该流道的综合性能最好。     

空冷凝汽器全工况运行特性分析

掌握火电站空冷凝汽器在各种工况下的运行特性,对于提高我国直接空冷机组的运行水平具有重要意义。以300MW直接空冷机组空冷凝汽器为例,分析了反映机组运行性能的汽轮机背压的影响因素。针对轴流风机全速和半速运行工况,计算得到了汽轮机背压随凝汽器凝结蒸汽量和进口空气温度的变化规律。结果表明：随凝汽器凝结蒸汽量和进口空气温度的增加,汽轮机背压增加;随轴流风机风速升高,汽轮机背压降低。轴流风机运行方式的调整,依赖于环境温度和机组热负荷的变化。对于冬季低温运行的空冷凝汽器,为防止出现汽轮机背压低于阻塞背压和凝汽器管束冻裂,风机需减速运行。反之,在夏季高温条件下运行的空冷凝汽器,为避免汽轮机背压过高带来的非正常停机和机组运行经济性的下降,风机需全速甚至超设计风量运行。     

换热器总传热量偏差的数值模拟研究

应用理论分析和数值模拟的方法，研究了换热器因各股流道流速分布不均匀而造成的总传热量偏差。研究结果表明，在恒壁温的条件下，当各流道流体流速不均匀程度达到4倍时，换热器的总传热量偏差在3%以内，而进出口压降将增加约23%。     

轴流泵运行工况对叶轮室进口预旋的影响

轴流泵叶轮室进口水流的流态对大型低扬程泵站水泵的安全、稳定和高效运行具有很大的影响。采用模型试验方法和三维湍流流动数值模拟方法,分别研究了轴流泵泵段装置叶轮室进口和立式轴流泵装置叶轮室进口的流态,得到以下主要结论：（1）叶轮室进口流态与水泵运行工况密切有关;（2）在正常运行工况范围内,叶轮室进口水流基本上为轴向流动,无预旋现象;（3）在小流量工况运行时,叶轮室进口的外圈水流出现与叶轮转动方向相同的预旋流动,但内圈水流仍向叶轮室方向流动,而中圈的水流则在预旋流动与轴向流动两种状态之间摆动;（4）轴流泵叶轮室进口在小流量工况发生预旋现象是泵内发生＂二次回流＂的内特性表现,水泵性能曲线出现马鞍形区则为其外特性表现。