基于遗传算法的叶片安装排序优化系统的开发及应用

叶片加工质量不均匀导致叶片安装后转子的不平衡量增加，动平衡工作量加大；旧机组现场更换叶片后，叶片更换前后在不同平衡面产生的不平衡力矩的变化将导致轴系不平衡增加，振动加大。为了减少叶片安装产生的不平衡量，在简要介绍遗传算法基本原理的基础上将其应用于叶轮机械叶片的优化排序安装，解决了以前采用穷举法对于大量叶片优化排序所碰到的求解时间长，得不到优化结果的问题。可以用于叶轮机械叶片的优化安装排序。     

基于应变的多平面动平衡检测方法

针对动平衡试验过程中配重面与不平衡面不一致而导致的转轴弯曲变形问题,提出了一种基于应变的多平面动平衡检测方法.采用转轴受力分析模型,在旋转坐标系下通过转轴各截面应变平均值计算出不平衡力.在转子试验台上对单轮盘和多轮盘上的不平衡量进行检测,并与不平衡量的实际结果进行比较.结果 表明:不平衡量的检测结果与实际结果之间的误差较小,表明本方法可以准确检测出多轮盘上的不平衡量.     

麦康600kW风力机现场动平衡研究

分析了风力机质量不平衡的产生机理及带来的后果,设计了风力机专用平衡带,提出了风力机现场动平衡的方法,并对内蒙古辉腾锡勒风场麦康(Micon)600kW风力机成功地进行了现场动平衡.平衡结果表明,所设计的风力机专用平衡带能够满足风力机现场动平衡的要求,具有工程应用价值,平衡后的风力机整机径向水平振动幅值比平衡前明显减小,充分证明了现场动平衡对风力机的重要性.     

现场动平衡方法实用指导

解决动平衡问题首要的一步是通过分析确诊振动故障是不平衡引起的.第二步得到表示不平衡的精确的振幅和相位值.为了成功地平衡转子,必须仔细地进行测量,以便使启动和停机次数减到最少.为了说明这个问题,表1示出了不同的相位误差可能达到的最好的不平衡下降率.当然,此时假设不平衡校正量是正确的.     

现场动平衡方法实用指导

旋转机械出现振动和破坏的最主要原因之一是转子不平衡.如果在现场能用校正重量的办法成功地平衡好转子,那么就可以大大减少停机时间和节省费用.然而现场动平衡会带来一些问题.主要涉及到为了得到实验数据需要时间、费用以及单纯地启动和停机产生的机械磨损.因此,本文介绍了为认识和解决较一般的现场动平衡问题而提出一些指导性意见,以便使动平衡的开机次数为最少.本文首先介绍振动分析技术,用它来验证哪些问题确实是不平衡问题,而不是可能误认为不平衡问题的转子松动、轴变形、共振、轴系不对中、偏心或其它问题.本文也讨论了可能影响动平衡数据的可重复性、转子弓形弯曲、温度梯度、热变形、负载效应、转速不重复及其它因素.同时还介绍了测量技术和引起测试误差的一般原因.然后针对适合现场的单平面和两手面平衡法对转子动平衡类型进行了分类,分为静不平衡、偶不平衡、准静不平衡和动不平衡四大类.其次介绍了为得到满意的平衡结果应该怎样选取试加重,包括试重的大小和位置.最后,介绍了为确定现场动平衡转子实用的平衡和振动容限所用的准则.     

600MW超临界机组转子不平衡故障分析与处理

分析了质量不平衡故障机理、原因和振动特征,针对某电厂2号600 MW超临界机组9号瓦及1号瓦轴振大的问题,进行了测试和分析,判断1号、9号轴瓦轴振大为不平衡量增大所致,分析了引起不平衡的原因。根据诊断结果,对1号、9号轴瓦进行了动平衡和抽高中压转子返厂处理。并与同类故障进行比较,给今后相似故障的分析处理提供参考。     

对V94.2型燃气轮发电机组的动平衡调试

质量不平衡是引起发电机组振动的一个重要因素,而现场动平衡技术则是解决其振动过大的一种有效途径。本文分析了不平衡振动的机理及动平衡谐分量法,并简介了该方法在V94.2型燃气轮发电机组的成功运用。     

平衡目标选择与全息动平衡法的改进研究

讨论了全息动平衡法中作为平衡目标的工频轨迹初相矢在描述转子平衡状态上所存在的问题.通过对转子工频轨迹的进动分解,详细分析了转子失衡量对正、反进动分量的不同影响.结果表明:反进动分量并非转子平衡状态的直接反映.在大偏心率轨迹的情况下反进动分量给失衡量估计带来的干扰不可忽略.在此基础上,提出了一种以转子正进动分量轨迹初相矢为平衡目标的改进全息动平衡方法.在不影响原全息动平衡法平衡精度的条件下,简化了配重方案计算过程,相比传统平衡方法而言更为准确和高效.现场应用实例验证了本方法的可靠性与有效性.     

离心风机现场动平衡技术的实践

本文在分析了通用离心风机回转系统不平衡振动产生的基本原因和特征的基础上，指出现场动平衡技术是解决风机振动问题的主要技术手段，并着重介绍了采用影响系数法进行现场动平衡的具体步骤和方法。最后，作者采用德国SCHENCK公司的Vibroport30现场平衡仪成功地对某厂出厂前6台No．6c号振动情况严重的风机进行了现场动平衡处理。     

某60Hz汽轮机转子高速动平衡试验研究

针对目前150 MW容量60 Hz机组高中压转子的高速动平衡试验进行了研究,采用基于有限元的转子轴承动力学软件Dyrobes建立了转子-轴承-摆架系统模型,在进行无阻尼临界转速及振型分析的基础上,结合模态振型平衡和影响系数平衡的特点,根据转子实测不平衡振动形式,合理选择平衡校正面和加重形式。最后,通过高速动平衡试验验证表明,该方法能有效减少启停机次数,节约平衡费用,同时可为这类国产小容量60 Hz汽轮机组转子高速动平衡提供技术参考和经验借鉴。     

Thermodynamics modeling of a novel nonpneumatic mechanical elastic wheel for predicting its mechanical–thermal behavior

An advanced thermodynamics model based on brush-type tire model was developed here to investigate the mechanical–thermal behavior of a novel nonpneumatic mechanical elastic wheel (ME-wheel), operating under rolling conditions. Herein, first, we proposed a novel brush-type tire physical model wherein the factors of realistic tire deformable and frictional behavior were introduced. Next, the heat generation and dissipation mechanism of ME-wheel was investigated to develop its thermal model. By combining the brush-type tire physical model and thermal model through the factors involving tire deformable energy loss and frictional power loss, we established this thermodynamics model to predict the temperature-dependent mechanical characteristics and corresponding thermal behavior of ME-wheel under rolling operating conditions. It is found that the computation results agree well with the obtained experimental data (tire static and dynamics testing), which demonstrated the capability of this model in precisely predicting the mechanical characteristics and thermal behavior of ME-wheel, particularly those designed for off-road vehicle under typical real operating conditions.     

机车轮箍防弛缓报警装置的研制

分析了机车动轮弛缓的原因,介绍了机车轮箍防弛缓报警装置的工作原理、结构特点及运用效果。     

无线汽车轮胎压力监测及预警系统的研究与实现

针对当前轮胎压力报警系统存在的问题,设计开发了能够实时检测轮胎压力、温度及状态的轮胎压力监测及预警系统,采用多级报警机制并实现检测结果无线传输,采取多种抗干扰及低功耗措施以提高系统可靠性,降低系统功耗,实现轮胎状态的准确检测,保障行车安全。     

A modified temperature integral approximation formula and its application in pyrolysis kinetic parameters of waste tire

A modified temperature integral approximation formula was proposed to calculate the kinetic parameters of tire pyrolysis. The relative error percentage of our formula was less than 0.02% at the range of 5 ≤ u ≤ 80. In order to validate our formula, the kinetic parameters of waste tire pyrolysis in a Thermogravimetric Analyzer (TG) were calculated according to different temperature integral approximation formula. The results demonstrated that the coefficient of the experimental TG and simulated TG from our formula was higher than that from Coats-Redfern method. The active energies of tire pyrolysis were 33.03 (120–300°C), 72.30 (300–420°C), and 50.83 kJ/mol (420–500°C).     

Energy conservation from systematic tire pressure regulation

The majority of US drivers do not consistently monitor the tire pressures in their vehicles. The 2000 TREAD Act, which requires automakers to gradually provide tire pressure monitoring systems for vehicles sold in the US will correct this problem for new vehicles. This law does not impact the problem in previously deployed vehicles, which have a turnover time of ∼20 years. A solution is provided here to address under-inflated tires on the current 220 million vehicles and the concomitant wasted energy due to increased rolling resistance in the US automobile fleet. This communication reports on a preliminary study of tire pressures in randomly chosen vehicles, which were undergoing oil changes at a combined retail/auto-care facility. The study indicates that substantial benefits would accrue if car care facilities systematically offered complimentary tire pressure checks with oil changes including: (i) increased safety by decreasing all crashes and saving more than 100 lives per year, (ii) reduced petroleum consumption by over a billion gallons/year, which would (iia) provide over $4 billion in economic savings for US consumers that could in part be recouped in retail/auto-care facilities, (iib) reduce greenhouse gas emissions by 13.5 million tons and automobile pollution and (iic) enhance national security.     

基于SIMULINK的某型车转向特性分析

汽车的转向特性是研究及评价现代汽车安全性能最重要的指标之一。当汽车处于高速、紧急转向的状态时,车辆容易失控,因此有必要对汽车的转向特性进行分析。根据给定的技术参数,建立汽车线性二自由度汽车动力学模型,利用MATLAB/Simulink软件建立汽车控制仿真模型,比较汽车在不同前轮角阶跃输入和不同车速下的车身姿态,研究汽车的转向特性,进而对汽车操纵稳定性进行评价。结果表明,汽车的行驶速度、前轮转角以及轮胎的侧偏刚度对汽车操纵稳定性有很大影响。当汽车以较低速度,较小的前轮转角行驶,并且选用较大侧偏刚度的轮胎是相对安全的。     

Assessment of the catalytic effect of various biomass ashes on CO2 gasification of tire char

The aim of this study was to determine the effect of various biomass ashes, comprising catalytically active components, on tire char reactivity during the CO₂ gasification process. Ashes from the combustion of corn cobs, beet pulp, sunflower husks and beech chips were selected for the research. Moreover, industrial fly ash from a coal-fired power plant was used as a reference. The tire char-ash blends with different ash contents (0–15 wt%) were gasified in the CO₂ atmosphere under non-isothermal conditions using dynTHERM Rubotherm thermobalance. Based on the n-order Coats and Redfern method, gasification reactivity indicators and kinetics parameters were calculated. The results showed that the addition of biomass ashes enhanced reactivity of tire char, and the magnitude of these changes depended on both the quantity and type of the additive. With the increase in the amount of added biomass ashes, the catalytic effect increased, and their efficiency can be ranked as follows: sunflower husk ash > corn cobs ash ≅ beet pulp ash > beech chips ash. In turn, reference fly ash from a power plant slightly affected the CO₂ gasification of tire char, regardless of its amount. Moreover, a statistically significant correlation between the reactivity indicator and the amount of K₂O, MgO and P₂O₅ in ashes analysed has been proved (reactivity indicator improved with an increase in these components amount). The performed analysis provides valuable information regarding the composition of catalysts characterised by high catalytic activity in the tire char gasification process.     

Conversion of waste tires to liquid products via sodium carbonate catalytic pyrolysis

This study deals with the pyrolysis of waste tires supplied from the transport industry. The base material of tire is latex, which is derived from natural rubber trees. Nowadays rubber (Hevea brasiliensis) is a fast-growing tropical tree crop, which is being cultivated for latex and ultimately for tire production. Waste tires can be recycled for energy and valuable materials in many ways; however tire burning is the most common practice for heat generation. In recent years, the catalytic conversion of waste tires through pyrolysis into liquid, solid, and gas products was investigated. Liquids product was produced from the catalytic pyrolysis of waste tire at high temperature (up to 600°C) using sodium carbonate (Na₂CO₃) as a catalyst. Thermo-physical characteristics of the produced liquid samples showed that up to 85% of the produced oil can be used in internal combustion engines. Gasoline and diesel fuel contents in the liquid products are 45% and 40%, respectively. The gas chromatographic (GC) analysis of the volatile fraction of pyrolysis products showed styrene (28.1%) and butadiene (10.7%) as dominant compounds. The gaseous phase includes C₁–C₄ hydrocarbons (4.8%) and the liquid phase includes C₅–C₈ hydrocarbons (6.5%) of the total products.     

小方坯帘线钢末搅参数的优化研究

以小方坯帘线钢的连铸生产为研究对象,采用ProCast商业软件根据实际生产的工艺参数建立铸坯的凝固传热模型,并利用射钉试验对模型进行校正以提高模型的准确性。结果表明,该凝固传热模型可以模拟帘线钢的连铸生产过程。根据射钉试验和数值模拟结果,对末搅位置进行改进,可发现铸坯中心缩孔等级下降,等轴晶率增大。     

Catalytic pyrolysis of olive cake and domestic waste for biofuel production

The development of waste-to-energy technologies provides an integrated approach to waste management, climate protection, and sustainable devolvement. In this study, biofuels were produced from “olive cake” combined with used paper and scrap tire. A lab-scale facility was designed to carry out catalytic pyrolysis of a solid feedstock comprising 5 wt% used paper, 5 wt% scrap tire, and 90 wt% olive cake. Jordanian volcanic tuff was used as a catalyst during pyrolysis. The catalytic pyrolysis produced various proportions of gaseous, liquid, and solid biofuels. The use of catalyst influenced the composition, quality, and yield of products via cracking and reforming reactions.