风电机组增速箱齿面黑线形成原因分析

针对风电机组增速箱齿面存在黑线的现象,结合风电机组的基本结构及运用特点,运用冲击理论解释了齿面出现黑线的可能,同时强调正确维护风电机组的必要性。     

花生油及其生物柴油的低温性能研究

对花生油及其制成的生物柴油的运动粘度随温度变化的规律及其低温性能进行了研究,并测定了花生油制成生物柴油后平均分子量的变化情况.结果表明:花生油制成生物柴油后,平均分子量降低,粘度显著降低,低温性能提高.     

提高机油温度对Z12V190柴油机低温启动的重要性

结合Ｚ１２Ｖ１９０柴油机机油预热启动减轻磨损的情况,论述了低温启动对柴油机造成的磨损,提出了以提高机油启动温度来降低柴油机磨损的措施。     

大功率水冷发动机低温预热起动系统的设计改进

为解决发动机的低温起动困难问题,依据液体加热器对发动机冷却系统循环加热的原理,设计了以液体加热器和发动机为核心的闭环系统,对原有安装方式进行分析和改进,通过试验验证,改进后的低温预热起动系统效果明显,使用效率高,安全可靠。     

兆瓦级风电机组主增速齿轮箱齿轮油加热系统研究

1引言兆瓦级风电机组是中国风电行业的主力机型,该机型需要适应中国各种复杂的环境条件,这为风电机组设计带来多重挑战,特别是冬季严寒的天气环境对机组的安全稳定运行挑战很大。本文就主增速齿轮箱润滑油加热系统以及加热控制逻辑等相关信息进行了详细的调研,参考有关国际国内标准和润滑油、添加剂厂商的技术经验,结合当前的实际应用     

计入齿圈柔性的风电机组行星传动动态特性研究

为研究齿圈柔性对风电机组行星齿轮传动系统动态特性的影响,将连续体的柔性齿圈离散成多段刚性轮齿段,以连接处的扭簧扭转刚度来量化齿圈的柔性特点.在行星架随动坐标系下,综合考虑啮合刚度、支撑刚度和齿圈柔性等因素,建立计入齿圈柔性的行星传动系统平移—扭转耦合动力学模型,继而分析齿圈柔性、齿圈支撑点数目与负载力矩对齿圈变形及系统...     

透平进气阀箱阀体稳定性及改型方案的数值研究

透平进气阀箱中阀体工作的稳定性与气流流动的稳定性密切相关,在数值计算的基础上分析了由于气流不稳定而产生的阀体振动对阀箱气动性能的影响,并对阀头和阀座的结构进行了改进,通过数值试验证明了这种改进措施能够稳定气流,从而有效地消除阀体振动,改善阀箱气动性能     

生物柴油混合燃料低温流动性的改进研究

探索通过添加不同比例的乙醇后对混合燃料低温流动性的改善效果。试验结果表明,20％黄连木生物柴油混合燃料,20％麻风树生物柴油混合燃料在乙醇添加比例为5％时,两种混合燃料的凝点、粘度都能下降到0#柴油的标准。     

基于余热利用的低温省煤器布置方案研究

低温省煤器可降低锅炉排烟温度,节省部分汽轮机的回热抽汽,对节约机组的能耗及提高电厂经济效益有重要意义.通过对低温省煤器布置及选型过程中所需注意问题的分析以及对其不同布置方案优缺点的比较,得出了在不同脱硫方式下低温省煤器的最佳布置位置,为余热利用的低温省煤器的布置及选型提供了依据.     

餐饮废油生物柴油低温流动性的改进研究

使用气-质联用仪测定餐饮废油生物柴油(WCME)和-10号柴油(-10PD)的组成,使用冷滤点试验器和运动黏度试验器测定WCME的低温流动性,同时使用调合、添加低温流动性改进剂的方法改进WCME的低温流动性。实验结果表明,WCME主要由饱和脂肪酸甲酯和不饱和脂肪酸甲酯组成,质量分数分别为27.63%和71.81%;WCME冷滤点为0℃,运动黏度(40℃)为4.41mm2/s;WCME与-10PD调合后,冷滤点降低,其中B20的冷滤点最低,为-13℃,运动黏度随着WCME的体积分数的减少,逐渐接近-10PD的运动黏度。通过添加低温流动性改进剂,WCME,B10,B20的冷滤点分别从0,-8,-13℃降至-4,-26,-25℃。     

Using transfer path analysis to assess the influence of bearings on structural vibrations of a wind turbine gearbox

Noise and vibration issues can be dealt with using several approaches. Using the source–transfer path–receiver approach, a vibration issue could be solved by attenuating the source, modifying the transfer path or by influencing the receiver. Applying this approach on a wind turbine gearbox would respectively correspond with lowering the gear excitation levels, modifying the gearbox housing or by trying to isolate the gearbox from the rest of the wind turbine. This paper uses a combination of multi‐body modelling and typical transfer path analysis (TPA) to investigate the impact of bearings on the total transfer path and the resulting vibration levels. Structural vibrations are calculated using a flexible multi‐body model of a three‐stage wind turbine gearbox. Because the high‐speed mesh is often the main source of vibrations, focus is put on the four bearings of this gear stage. The TPA method using structural vibration simulation results shows which bearing position is responsible for transmitting the highest excitation levels from the gears to the gearbox housing structure. Influences of bearing stiffness values and bearing damping values on the resulting vibration levels are investigated by means of a parameter sensitivity study and are confirmed with the results from the TPA. Because both the TPA and the parameter sensitivity analysis revealed a big influence on radial stiffness for a certain bearing, this was investigated in more detail and showed the big importance of correct axial bearing position. The main conclusions of this paper are that the total vibration behaviour of a wind turbine gearbox can be altered significantly by changing both bearing properties such as stiffness, damping and position, and bearing support stiffness. Copyright © 2014 John Wiley & Sons, Ltd.     

Effects of intake air temperature on SI engine emissions during a cold start

This paper presents the concept of preheating the intake air to reduce cold-start emissions from gasoline engines. The effects of intake air temperature on emissions from a gasoline engine were studied by using an air heater based on spark ignition. A light-duty vehicle test of cold-start emissions was carried out at an ambient temperature of?7°C according to New European Driving Cycle for Euro 3 and Euro 4 exhaust emission legislations. The results showed that preheating the intake air could effectively reduce both hydrocarbon (HC) and carbon monoxide (CO) emissions and improve fuel economy during a cold start. During idling conditions, the key phase of the HC and CO emissions was the first 40 s. With the aid of the air heater, cold-start HC and CO emissions from the vehicle were lower than the limit values in the Euro 3 and Euro 4 regulations.     

Multi‐body modelling and analysis of a planet carrier in a wind turbine gearbox

There have been some recent efforts to numerically model and analyse the wind turbine gearbox. To date, much of the focus has been on increasing model refinement and demonstrating its added value. This paper takes a step back and examines in detail the modelling and analysis of an important wind turbine gearbox component, the planet carrier, in a multi‐body setting. The planet carrier studied in this work comes from the 750 kW wind turbine gearbox used in the National Renewable Energy Laboratory's Gearbox Reliability Collaborative project. The study is performed in two parts. First, the influence of subcomponents mated to the planet carrier in the gearbox assembly is investigated in detail. These components consist of the planet pins, bearings and the main shaft. In the second part of the study, the flexible body modelling of the planet carrier for use in multi‐body simulations is examined through the use of condensed finite element and multi‐body simulation models. Both eigenvalue analyses and time domain simulations are performed. Comparisons are made regarding the eigenfrequencies, categorized mode shapes and the maximum and minimum planet carrier rim deflections from the time domain simulations. The mode shapes are categorized into seven distinct deformation patterns. An actual load case from the dynamometer tests, a 100% rated torque loading, is used in the time domain simulations. The results from this comprehensive study provide an insight into the proper modelling of a wind turbine planet carrier in a multi‐body setting. Copyright © 2012 John Wiley & Sons, Ltd.     

余热(水)冷热联供系统在洗浴行业的应用

通过工程实例介绍余热(水)冷热联供系统在洗浴行业的应用,计算各种加热系统理论能耗,比较各系统的经济效益,认为该系统在洗浴行业也将会得到更加广泛的应用和发展。     

Analysis of Heat Transfer Behaviour of the Conduction Cold Plate System

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空气源热泵热水器与电热水器耦合选型研究

阐述了空气源热泵热水器选型的影响因素,对冷热水温度、干球温度、相对湿度和设备COP、结霜等影响因素进行了说明,给出了空气源热泵热水器和电热水器耦合使用时的选型方法,并利用贴现指标法对二者按不同配置时的经济效益进行比较分析,从而获取最优配比。     

小型风电泵水系统控制方法的研究

概述风力提水系统的发展历程，分析了小型风电泵水系统的主要构成及原理。论述了SPWM的产生原理，设计了单片机控制系统的软硬件。以1kW的风电泵水系统为对象进行了试验，其输出的机械特性表明采用该控制方法具有较好的动态性能。     

冷介质通过井筒注入某地质结构的流动与传热预测软件研发

通过井筒向某地质结构内注入冷介质时,由于地温与冷介质之间存在温差,冷介质将通过井筒结构与土壤进行热量交换,最终导致冷介质冷量损失进而温度升高而达不到所需温度要求。因此,在施工前,需要对井筒进行冷量损失和沿井筒的温度分布的预测,为保冷结构设计以及井筒结构材料选型提供数据支持。由于注入冷介质的过程中,热量交换过程是一个非稳态传热过程,通常只能采用数值模拟来进行预测。为了简化数值模拟复杂的计算过程,采用准稳态的传热方法来构建单相冷介质通过井筒注入时的流动换热的物理数学模型,并开发了一个数值仿真软件。将仿真结果同商业软件FLUENT模拟结果进行了比较,表明温度分布和冷量损失基本一致,由此验证了所提模型的正确性和可靠性,为非工程热物理专业的工程技术人员提供能够预测低温工质在井筒流动与换热过程的仿真软件。     

Analysing the effect of the laeh in the storage tank on the performance of a tsaeh

When an auxiliary electric heater (AEH) is incorporated in a thermosyphon solar water system, the system performance becomes more complex and it is more difficult to simulate and analyse its operational characteristics. Using a ‘fixed-node, equally-convecting-mixing model’ that they have developed, the authors perform detailed simulations and analysis of the effects of the location of the auxiliary electric heater (LAEH) in the storage tank on the performance of the thermosyphon solar water system with an auxiliary electric heater (TSAEH), and discover for the first time some new laws governing the system operation. The authors believe that their simulations and analysis will be very beneficial for optimal design and practical application of such systems in the future.