高速动力车轴承失效分析及其托架结构改进

对高速动力车托架轴承失效进行了分析,发现轴承润滑油中含有大量水分是导致轴承失效的直接原因。对动力车在高速状态下的特性及其与环境的关系等认识不足,托架油箱结构设计考虑不周是造成托架箱进水,进而导致托架轴承系统失效的根本原因。采取了开排水孔、通气孔等改进措施,解决了高速动力车托架轴承失效问题。     

高速动车组轮对轴箱轴承温度监控技术优化改进

轮对轴箱轴承温度监控技术是现代高速动车组技术的重要组成部分。轮对轴箱轴承温度监控可以防止轴承和轴端因为高温导致的车轴断裂和出轨现象的发生。主要介绍了对高速动车组轮对轴箱轴承温度监控技术进行的优化改进工作。     

高速重载滑动轴承试验

1 前言高速重载滑动轴承的设计与试验研究课题是航空部七五重点科研项目“航空发动机体内减速器结构完整性”中的一个分课题。该课题包括两个项目:一个是发动机主轴滑动轴承,其攻关指标是轴颈线速度V≤100m/s,比压P≤3.0MPa,第二个项目是行星架齿轮滑动轴承,其攻关指标是轴承润滑面的线速度V≤20m/s,比压P≤6.0MPa。从上述攻关指标可以看出,高速重载滑动轴承要在PV值为≤300MPa.m/s条件下     

DF4D 型机车轮对空心轴驱动轴承的故障分析

介绍了 JK430装置对各类机车轴承的监控效果，并结合实际应用情况对监测装置的可靠性进行了客观的评价，从运用角度对空心轴驱动轴承故障的原因进行分析并提出应对措施。     

风电机组齿轮箱高速轴端轴承热-应力耦合故障分析

建立了风电机组齿轮箱高速轴端轴承的热阻网络模型,研究了在变风速、变载荷情况下轴承的动态热特性.采用Ansys Workbench有限元方法进行三维热-应力耦合分析,并模拟轴承及其在故障条件下的温度、形变及热应力特征.结果表明:风速、轴承内圈和滚动体之间的接触热阻及润滑油的对流接触热阻对轴承的温度有显著影响;轴承正常运行时,最大形变出现在内圈与滚动体接触面,最大热应力出现在外圈外表面边缘;当轴承出现胶合以及磨损故障时,其温度分布、热流量及热应力均有不同程度变化.     

船用轴流压气机推力轴承特性计算及试验研究

为获得某新型推力轴承在某船用轴流压气机中的工作特性并进行试验验证,基于ARMD Bearings软件及自编程序对推力轴承特性进行了模拟计算,在全尺寸高速大推力滑动轴承试验台上进行了轴承特性试验研究,并在实机台架试验中对轴瓦温度进行了监测。计算分析了15种工作条件下油膜的压力、厚度、温度、刚度、阻尼及能量损失与推力和转速关系。轴承特性试验主要包括9种稳定工况下的性能试验,以及轴承超载、超速试验中每块轴瓦表面温度及油膜压力的测量。结果表明：模拟计算结果及试验测试得到的油膜温度、压力随推力及转速变化规律基本一致;轴瓦表面最大油膜压力位于支承块背部附近,与推力基本呈线性关系;转子转速越低、推力越大,则油膜厚度越小、油膜刚度及阻尼越大;转子转速越高、推力越大,则油膜温度越高、能量损失越大;在设计点轴承运行参数均有一定安全裕度,该推力轴承可以满足机组使用要求。     

M701DA燃机高速动平衡试验成功

2月10日21时，M701DA戚墅堰1#燃机转子成功完成高速动平衡试验，压气机侧和透平侧轴振均在合格范围内，标志着东汽在燃气轮机转子高速动平衡方面有了实质性的突破，并积累了宝贵的经验。在场的监造代表与用户代表对此极为满意。     

风电齿轮箱高速轴轴承疲劳寿命及动态可靠性分析

为探究风电机组齿轮箱高速轴圆柱滚子轴承在服役过程中的疲劳寿命和可靠度变化规律,以新疆达坂城风场年度风载荷为外部激励,建立基于威布尔分布的随机风速模型及考虑内部齿轮时变啮合刚度、轴承时变刚度等激励因素的风电齿轮传动系统齿轮-轴承耦合动力学模型,通过Newmark积分法求解高速轴轴承动载荷。运用雨流计数法及Goodman平均应力修正法得到对称循环应力,结合线性损伤理论和非线性损伤理论的对比,获得轴承的接触疲劳寿命和动态可靠度。结果表明：额定功率下,在外部随机风载激励和内部齿轮-轴承耦合共同作用下,内激励仍然对系统高速轴轴承动载荷起主要作用。与线性损伤累计理论相比,非线性损伤累计理论考虑载荷加载的顺序效应,能更好地描述轴承在整个疲劳寿命过程中各阶段的疲劳损伤情况。轴承在服役过程中,前15年的损伤较小,可靠度衰减缓慢,而在后期可靠度呈现出非线性迅速下降趋势,应及时调整维护策略。     

高速动力车车体结构的研究

整体承载是在高速动力车车体结构上采用的一种新的机车车体承载方式。沿车体纵、横及水平方向组成一定数量的封闭框架,并由网格梁配合承载蒙皮实现了这一承载方式。通过建立良好的车体结构计算仿真模型,在对采用新型结构的高速动力车车体结构进行大量分析计算的基础上,在保障安全、保证刚度、强度的前提下,实现了车体结构的轻型化。车体结构静强度试验验征了结构的合理性和计算的有效性。     

用于带轴涡轮转子超速试验的电磁轴承控制器设计

本文提出了在转子超速试验中利用电磁轴承控制振动的设想。通过对电磁轴承及带轴涡轮转子系统模型的建立和研究，获得系统状态方程和传递函数，并介绍了一种利用根轨迹法，求取PID控制器参数的设计方法。仿真控制结果表明，该装置可以减弱转子振动，实现在超速试验下平稳运行。     

机车水阻试验中柴油机转速信号的提取

介绍了机车在水阻试验中柴油机转速信号的测取方法,此方法利用主发电机整流电压的脉动频率转换为转速的原理,方法简单,测量准确。     

内燃机车水阻试验中柴油机转速的检测

介绍了一种内燃机车水阻试验中柴油机转速检测的新方法。该方法的转速信号取自与柴油机同轴相连的发电机,并采用锁相环技术实现信号的倍频。实践证明,该检测方法易于操作,测速准确、稳定,精度高,有效地减轻了劳动强度,提高了生产效率。     

Real-time test results with adaptive speed controllers for a dieselprime-mover

Self-tuning adaptive control algorithms, that employ explicit dead-time identification techniques, have been discussed in the literature vis-a-vis the diesel-driven power prime-mover. Such algorithms are numerically intensive owing to the complicated identification algorithms. This paper discusses the implementation of the above mentioned algorithms on a Texas Instruments' DSP 320C30 based system. This digital signal processor has sufficient numerical capability to carry out all the real-time computations at sampling intervals of 10 ms. It can also perform well in the matters of speed measurement and control generation without any significant additional hardware. The results of real-time tests are compared with that obtained using the Woodward Governor Company's 701 prime-mover controller     

变频调速技术在涡轮增压器试验台上的应用

介绍了交流变频技术在涡轮增压器试验台上的应用及原理,采用变频技术后,不但使增压器转速控制更准确、简捷,而且提高了压气机空气流量测试精度。     

转速控制对水力机械模型试验精度的影响

模型试验是国际普遍采用的检验和改进水力机械设计的主要方法.文中介绍了水力机械模型试验转速控制方式,讨论了模型试验误差产生的原因、种类和计算方法.结合某模型试验台转速控制对试验精度产生的影响,进行了分析,并采取了措施,保证了试验精度.     

基于正交试验的低速机增压器涡轮排气壳性能优化研究

为提升船用低速机涡轮增压器性能,对增压器涡轮排气壳底部流道结构进行参数化,设计并开展了以效率为优化目标的四因素三水平正交试验优化设计和增压器整机性能试验。首先,采用CFD数值模拟方法对不同参数组合的涡轮气动性能进行了计算,然后对涡轮排气壳底部流道结构参数开展了灵敏度分析,同时针对不同参数组结构开展了内部流场对比分析,明确结构因素对流动的影响机理;在此基础上对优化后方案开展了涡轮特性分析,最后在低速双燃料机平台上开展增压器整机试验验证。分析研究表明：在涡轮进气壳、喷嘴环和涡轮叶片等通流部件结构不变的前提下,涡轮排气壳排气方向轴向长度对涡轮整级效率的影响最大,优化后效率明显提升,设计点总压损失系数降低0.3874,静压恢复系数提升0.537,总静效率提升1.85%,其余工况总静效率最大提升2.4%。试验结果表明：优化后涡轮增压器整机效率在主机燃油模式和燃气模式下的全工况范围内效率均有提升,最大提升幅度分别达到1.4%和2.1%,涡轮性能和增压器整机性能改善明显。     

An economic comparison of a fixed speed,a two speed,and a variable speed vapour compression heat pump

The seasonal performances, accounting for steady state conditions and on/off cycling losses, of a conventional fixed speed, a two speed, and a variable speed vapour compression heat pump have been determined for the annual heating demand of a large detached house. An economic analysis of the energy savings shows that, compared with a conventional fixed speed heat pump, the two speed, simple variable speed, and microprocessor-controlled heat pumps have pay-back periods of two, six and five years respectively.     

Drive train dynamics assessment and speed controller design in variable speed wind turbines

This paper deals with the speed controller design in DFIG based wind turbines, and investigates stability and performance of the drive train dynamics against different control strategies. It is shown that speed controller design based on the single mass drive train model may result in unstable mechanical modes, because it ignores the dynamics of the flexible shaft. Then, another control approach, known as feedforward compensation of the shaft torsional torque, is examined. It is shown that this control method results in poorly damped oscillations of torsional torque and turbine speed during the transient conditions. The open loop transfer function from the electromagnetic torque to the generator speed contains a dual quadratic function representing the dynamics of flexible shaft. The dual quadratic function comprises resonant and anti-resonant frequencies that greatly affect the stability of the drive train dynamics. Next, a step-by-step procedure for designing the speed controller based on the two-mass drive train model is proposed. The proposed speed controller provides stable closed loop system, zero tracking error, low-frequency disturbance rejection, and open-loop gain attenuation at the resonant frequency. At the end, performance of the proposed controller is investigated by the time domain simulations.     

Environmental performance and economic analysis of all-variable speed chiller systems with load-based speed control

There are increasing views on implementing all-variable speed chiller plants in place of conventional constant speed plants. Supporters of these views claim that all-variable speed chiller systems can operate much more efficiently at part load in response to changes in building cooling load. This paper introduces load-based speed control for all-variable speed plants to optimize their environmental performance. Thermodynamic-behaviour chiller system models were developed to perform environmental assessment (in terms of annual electricity and water consumption) for typical constant speed and all-variable speed chiller systems operating for the cooling load profile of a local office building. Operating cost differences between the two systems were calculated and compared in an economic analysis. Applying load-based speed control to the variable speed chiller plant can decrease the annual total electricity use by 19.7% and annual water use by 15.9% relative to the corresponding constant speed plant. The significance of this study is to provide more insights into how to make chiller systems more sustainable.