汽轮机低压末级叶片动频试验研究

新开发的低压末级叶片采用自带冠式整圈自锁阻尼围带、自带凸台式阻尼拉筋的叶片结构形式,为验证并调整叶片的共振频率,使其在考核转速范围内不存在规定节径数的三重点共振,须对其进行动频试验研究。开发了基于WiFi通信的动态应变遥测方法和基于单喷嘴压缩空气射流激振方法的汽轮机叶片动频试验系统。考虑叶片静频和周向均布等因素,在整圈叶片中挑选总数10%的叶片作为被测对象,对应变片采用掩膜定位,对导线采用封胶、蒙皮等工艺,保证测量精度和测点完好率。试验表明：被测叶片三重点共振频率在转速较低时分散度较大,随着转速升高分散度减小;围带切削减薄,降低了围带刚度,改善了接触状况,有利于减小动频分散度。     

拱型围带整圈连接叶片组固有频率计算和调频探讨

采用有限元法计算拱型围带的刚度并识别其与叶片连接处的边界条件，沿用叶片弯扭耦合振动和整圈连接传递矩阵理论，建立了拱型围带和拱型围带加松拉筋结构整圈连接叶片组固有频率计算模型方法。并比较了实物动，静频的计算和实测结果，表明二者吻合较好。对此类结构叶片的调频作了深入的研究，提出了调频方法。     

加工装配对整圈自锁阻尼叶片频率影响的研究!

目前在应用CAE/FEA软件对汽轮机整圈自锁叶片进行结构分析时,加工装配对频率结果的影响程度一直没有得到确认。从整圈自锁阻尼叶片的有限元分析方法入手,着重对不同相邻围带间隙对频率结果的影响进行探讨,并将有限元数值模拟的结果和试验结果进行了对比;通过分析加工装配对整圈自锁阻尼叶片的影响,将叶片加工装配后的相邻叶片围带间隙测量结果放入有限元计算模型中,解决了长期以来有限元计算结果与试验结果的偏差问题,对指导动频试验有非常积极的作用。     

有限元技术在空冷汽轮机长叶片设计中的应用

首先采用有限元技术对某空冷汽轮机低压末级长叶片的整圈振动特性进行计算,随后时由整圈自锁长叶片围带和凸台不同接触间隙造成整圈振动特性的变化进行了数值分析,最后对空冷低压长叶片各个部分的强度进行了分析.有限元计算结果与动频试验的结果偏差很小,强度计算结果也满足设计规范的要求.这些先进计算技术的应用,大大缩短了长叶片的研发周期,保证了空冷低压长叶片的安全运行.     

复杂阻尼结构对910mm整圈自锁叶片振动特性的影响

对整圈自锁叶片的围带与凸台的结构进行优化,可以有效地提高叶片刚度,减小应力,从而提高汽轮机运行的安全可靠性。但是另一方面在汽轮机变转速过程中,围带和凸台的自锁状态会对叶片动频造成重要的影响。本文以910mm整圈自锁叶片为例,通过计算对叶片围带和凸台的自锁情况进行了考查,其结果得到了试验测量的验证。     

核电汽轮机整圈自锁叶片二阶动频的调频分析

重点探讨了核电汽轮机整圈自锁动叶片动频调整手段,通过计算和试验对比分析表明,采取改变叶片拉筋特征尺寸的办法,对二阶频率调整是简单而有效的,并最终确定了长叶片的拉筋特征尺寸。试验表明,核电汽轮机长叶片的设计是成功的,叶片能满足机组安全运行。     

核电汽轮机1710 mm末级长叶片整圈振动特性分析

分别用专用计算程序GRPBLD和大型有限元程序Abaqus对1710 mm低压末级动叶片的整圈振动特性进行了分析,两种计算方法均准确地预测了1710 mm叶片的"三重点"共振区域,保证了动频试验的圆满完成,证明通过其设计的1710 mm叶片是成功的,设计方法是有效的。     

核电汽轮机1710mm末级长叶片整圈振动特性分析

分别用专用计算程序GRPBLD和大型有限元程序Abaqus对1 710 mm低压末级动叶片的整圈振动特性进行了分析,两种计算方法均准确地预测了1 710 mm叶片的“三重点”共振区域,保证了动频试验的圆满完成,证明通过其设计的1 710 mm叶片是成功的,设计方法是有效的.     

1220mm全速湿冷末级长叶片强度振动分析

详细分析了上海电气1 220mm长叶片的强度、振动特性,以及叶片围带、拉筋等阻尼结构对振动频率的影响。分析表明,该叶片为2阶调频叶片,强度、振动特性良好;同时采用整圈计算、循环对称两种算法验证了结果的可靠性。叶片动频试验结果与理论计算相吻合,标志着该叶片的成功开发。     

某型核电汽轮机次末级叶片失效原因分析及优化改型设计

介绍了某型核电汽轮机次末级叶片的失效情况,并根据失效叶片断口分析和动频测量试验结果分析了叶片失效的原因。针对叶片失效的原因提出了优化设计方案,优化型叶片采用了能够提高结构阻尼的凸台拉筋整圈连接结构,并通过调频试验使叶片的共振转速避开2 820r/min~3 090r/min,以保证优化型叶片的安全运行。     

柴油发电机组整机振动及防振

简要分析了柴油发电机组的振动对外界和电站内部零部件的影响,及外部振动同样会引起电站振动和电站内部零件的损坏,在此基础上提出柴油发电机组的防振措施。叙述了隔振器的性能特点以及选择隔振器的方法和步骤,给出隔振弹性支承的主要参数和计算方法,最后指出隔振弹性支承的布置力求对称以减少独立和耦合振动型式。     

New cascades for thermo-chemical refrigeration

A diagrammatical approach for the design of new thermo-chemical cascades for heat management purposes is proposed. The two key elements of this approach are: a method to automatically generate system architectures and a general approach to selecting appropriate materials. It is based on establishing an explicit correspondence between the exergy balance around a thermo chemical system, the properties of the reactants and the operational system parameters. A new auto thermal configuration involving two thermally coupled single effect processes is proposed and suitable materials for its implementation are identified. The method is illustrated for the design of an experimental installation for the testing of a thermo-chemical refrigeration system operated at distance from a heat source.     

Hydrogen looping approach in optimized methanol thermally coupled membrane reactor

In this study, cyclohexane and hydrogen loop approach is proposed in optimized thermally coupled dual reactors in methanol production via Differential Evolution (DE) method. This new generation of thermally coupled membrane reactors uses simultaneously the advantages of hydrogen carrier characteristic and multifunctional reactors. This configuration is named thermally coupled dual methanol reactor (TCDMR). In the first reactor, cyclohexane dehydrogenation reaction is coupled with methanol production reactions. Cyclohexane is produced in the second reactor due to carrying all produced hydrogen from the first reactor to the second reactor for benzene hydrogenation reaction. The operating conditions of TCDMR are optimized via DE method and six decision variables are considered to investigate its performance. Since cyclohexane is produced continuously in the second reactor and enters the first reactor as the endothermic feed, the external cyclohexane injection rate is minimized, too. A comparison is made between the optimized TCDMR (OTCDMR), TCDMR and Thermally coupled methanol reactor (TCMR) and conventional methanol reactor (CMR). The modeling results demonstrate the superiority of OTCDMR to all previously proposed configurations. A continuous system is achieved and slight amount of exterior cyclohexane injection rate (3.6 mol h⁻¹) is required in this configuration. Furthermore, the hydrogen storage problem is solved by this configuration owing to simultaneous hydrogen production and utilization. In addition, produced benzene in OTCDMR is about 10% of the one in TCMR which can be appealing from the environmental viewpoint.     

高性能钢—混组合板激励响应动力特性试验

基于楼板振动性能研究现状,通过研发的空气调频激励装置及其测试方法,以压力传感检测系统为核心控制参数,提出装配式高性能钢-混组合板模型,进行激励响应动力特性试验。结果表明,该种动力特性时程分布特征由瞬态阶段、稳态阶段和衰减阶段三种状态组成,不同位置处激励响应传播特性一致,加速度、位移、应变等动力响应幅值均不同。该方法可应用于大型水工建筑物板结构及组合楼板结构基频测试与识别等实际工程中。     

基于频响法的变压器绕组变形无线低功耗板载检测系统研制

频率响应法是检测变压器绕组变形的有效方法,目前多是采用有源供电、长距离信号连线的方式开展测试。测试现场取电困难、电源质量无法满足高精度测试要求的问题时有发生,长距离信号连线叠加杂散参数降低数据准确度及一致性的问题亟待解决。文章基于频率响应法的检测原理,研制了能够电池供电的无线低功耗板载检测系统,解决了现场电源、信号长距离传输畸变等问题。针对真型变压器绕组的检测结果表明,相同条件下,无线低功耗板载检测系统2次检测幅频特征曲线的相关系数为0.982,与标准检测系统幅频特征曲线进行比较得到的相关系数为0.951,证明该系统具有较高的检测一致性及准确性。     

A Coupled Pressure-Based Finite-Volume Solver for Incompressible Two-Phase Flow

This article reports on the formulation and testing of a coupled pressure-based algorithm for the solution of steady incompressible disperse two-phase-flow problems. The method is formulated within a Eulerian-Eulerian framework in the context of a collocated finite-volume scheme. An equation for pressure is derived from overall mass conservation following the segregated mass conservation–based algorithm (MCBA) approach and using an extended two-phase flow form of the Rhie-Chow interpolation technique. The newly developed pressure-based coupled solver differs from pressure-based segregated solvers in that it accounts implicitly for the pressure–velocity and the interphase drag couplings that are present in disperse multiphase flows to yield a system of coupled equations linking the velocity and pressure fields. The performance and accuracy of the coupled multiphase algorithm are assessed by solving eight one-dimensional two-phase flow problems spanning the spectrum from dilute bubbly to dense gas–solid flows. Each problem is solved over three grid systems with sizes of 10,000, 30,000, and 50,000 control volumes, respectively. Results are compared in terms of iterations and CPU time with similar ones generated using the segregated MCBA-SIMPLE algorithm. The newly developed coupled solver is shown to yield substantial decrease in the required number of iterations and CPU time, with the rate of solution acceleration varying between 1.3 and 4.6.     

联合循环机组的数学模型及其参数辨识研究

联合循环电站由于其复杂的控制系统和强耦合的非线性关系,其数学模型非常复杂,开展联合循环机组的建模和参数测试研究具有重要的学术意义和工程应用价值。本文提出了适用于电网一次调频和稳定性分析的联合循环电站模型,采用改进最小二乘参数辨识方法对某400MW联合循环机组的模型参数进行了辨识,采用辨识的参数进行了仿真分析并与机组运行的实测数据进行了对比,两者能够很好地吻合,证明了所提出模型和辨识方法的有效性,为联合循环电站的一次调频和动态特性分析奠定了基础。     

用火焰原子吸收光谱法测定钴基合金焊丝S111中铁和镍

研究了用火焰原子吸收光谱法连续测定钴基合金焊丝S111中的铁和镍元素含量的方法,确定了仪器的最佳工作条件,如：波长、光谱通带宽、灯电流、燃助比等,并详细介绍了测试中合适的溶样方法、酸度及基体干扰等问题.     

转子系统耦合故障特征的实验研究

汽轮机组除了出现单一故障之外，还常常会出现两种或两种以上故障耦合的情况。但目前对耦合故障转子系统的动力学和故障机理的研究还比较少，针对上述情况并基于工程实际的需要，对转子系统的某些耦合故障进行了模拟实验研究，利用频谱分析技术、小波分析对测到的振动信号进行了分析，以便为转子系统的该类故障的诊断和预防提供有益的参考。     

基于ETAP软件的矿热炉负荷谐波影响评估与治理

针对矿热炉负荷产生的谐波问题,给出了采用ETAP软件的负荷谐波影响评估方法。将矿热炉负荷谐波特性添加到用户自定义谐波源,搭建了谐波分析模型,进行谐波潮流计算,评估公共连接点母线的谐波水平。依据谐波评估结果,设计滤波器。利用ETAP的谐波频率扫描,找出滤波器投入后系统的并联谐振点,对滤波器投入后的效果进行谐波潮流分析。结果表明,所设计的滤波器达到了预期的滤波效果,仿真计算结果和实际测试基本吻合。利用ETAP软件进行谐波仿真分析和谐振分析,可以辅助进行滤波器设计,能避开系统谐振点,有效减少电网的谐波污染。