IC卡施工限速控制应用技术研究

提出了集运行揭示及施工限速监控装置IC卡控制信息管理于一体的IC卡施工临时限速跨机务段编写软件的开发思路 ,解决了在同一机调室多个机务段乘务员出乘情况下运行揭示、监控装置IC临时限速控制信息的一段编辑、自动分解、跨段写卡的技术问题 ,拓展了监控装置IC卡临时限速功能 ,确保列车在施工限速区段的安全控制     

小型水平轴风车侧偏限速机构的设计计算

本文分析了小型水平轴风车侧偏限速机构的工作原理,导出了尾舵复位力矩的准确表达式,指出尾舵不完全顺风产生的气动力,是尾舵平衡力矩的来源。在此基础上得出了侧偏限速机构的优化设计方法,经实际应用证明,这种设计方法是行之有效的。     

TN480G型汽油机设计

ＴＮ４８０Ｇ型汽油机设计太原内燃机厂段双喜１概述国外先进的叉车用汽油机，具有最高转速自动限速机构及驱动叉车液压系统工作的液压动力输出机构，从而使叉车结构紧凑，整机作业安全可靠。以前国内无叉车专用汽油机，都采用汽车用汽油机作动力。汽油机无限速机构及液压...     

离网型风力发电机的大风限速保护研究

如果解决不好离网型风力发电机的大风限速保护问题,就会大大地降低其可靠性和安全性.文章从风轮与发电机的匹配人手,一改传统离网型风力发电机最佳功率匹配运行为峰前匹配运行,使风力发电机在大风时保持较低的风能利用系数,具有大风时的限速保护作用.     

二分法求解牵引计算紧急制动限制

为提高牵引电算中求解列车紧急制动限速的效率,将列车紧急制动工况下的换算制动率、闸瓦换算摩擦系数、列车基本阻力、加算坡度、计算制动距离转换成相应的方程,利用二分法求解列车的紧急制动限速.仿真计算证明,该文法减少了迭代次数,提高了计算精度并取得了良好的时间复杂度.     

对列车运行监控器两个汇编条件的探讨

1　关于ＺＴＬ控制1.1　现行控制模式　　ＺＴＬ状态下 ,一方面控制最高限速 ,列车运行速度超过最高限速时 ,常用紧急动作 ;另一方面模拟ＺＴＬ工作报警方式 ,即机车速度大于最小报警速度后 ,黄、双黄、黄 2、绿黄转白 2 2ｓ内或红黄灯情况下 ,解锁 4ｓ间隔 ,报警 7ｓ自停。1.2     

监控装置在限速地点前自停后列车超速的原因分析和建议

用牵引计算方法,从机车车辆制动性能和机车监控装置制动模式控制两方面,对两起限速地点列车超速原因进行了深入分析.     

基于国6排放法规要求的活塞环优化设计

基于国6排放法规要求以及国家碳达峰碳中和政策,分析了整车排放状况与发动机活塞环设计的关系,提出通过采用更先进的活塞环设计技术来解决整车在同等排放下提升最高限速的问题。针对发动机活塞系统活塞环的设计现状,提出活塞环的优化设计方案,并运用AVL-Excite Piston&Rings软件进行模拟仿真,分析活塞环优化前后的发动机机油消耗对比情况。通过整车排放验证和发动机台架验证数据发现,实施活塞环的优化方案可有效降低发动机的机油消耗水平,降低颗粒物(Particulate Matter,PM)排放水平,从而提高整车限速值。     

小型风力机大风限速方法的发展与研究现状

总结了小型风力机常用的大风限速方法的发展与研究现状,介绍了具有风轮侧偏机构的风力机和被动变桨矩风力机的结构动力学的研究进展,以及尾舵空气动力学和结构动力学的研究现状.     

S195柴油机噪声的现状及其降噪措施

本文分析了S195柴油机噪声水平,提出多种降噪途径,如减小空气动力噪声、降低燃烧及机械激振力、改进结构振动特性等以及运输用的限油、限速及高效消声器等措施。     

Experimental and numerical study on the combustion limiting characteristics and design margin of a marine diesel engine

In this paper, a working-process simulation model was established, and the characteristics regarding the diesel engine maximum output power were analyzed under different limiting parameters. The design margin of the marine diesel engine is obtained through numerical and experimental study. Then, the simulation model and single cylinder diesel engine test were used to investigate the theoretical determination method of limiting characteristic lines and design margin area. It can be found that using least-square method to fit the calculation results can achieve quantitative analysis of limiting characteristics, and then the design margin area can be confirmed. The analysis results show that the maximum output power of the diesel engine is limited by in-cylinder pressure, turbine speed and exhaust temperature. The limiting parameters of maximum output power are different at different speeds, and the trend with speed of maximum output power are also different under different limiting parameters. Furthermore, the analysis of the operating area shows that the margin of the marine diesel engine at rated speed is about 27%, and there is a large design margin when operating at high speed.     

新型的极限调速器──CB01型超速保护卸油装置

本文介绍了一种新型极限调速器的工作原理和特性．它是在液压调速器原理基础上研制的，克服了机械式调速器笨重、正反车保护转速相差较大的缺点，具有本积小、重量轻、工作转速稳定可靠的特点．     

Reactive power capability of a wind turbine with doubly fed induction generator

The aim of the work is to derive a steady state PQ‐diagram for a variable speed wind turbine equipped with a Doubly Fed Induction Generator. Firstly, the dependency between optimal rotor speed and wind speed is presented. Secondly, the limitations in reactive power production, caused by the rotor current, the rotor voltage and the stator current are derived. Thirdly, the influence of switching from Δ to Y coupling of the stator is investigated. Finally, a complete PQ diagram for a wind turbine is plotted. It is concluded that the limiting factor regarding reactive power production will typically be the rotor current limit, and that the limit for reactive power absorption will be the stator current limit. Further, it is concluded that the rotor voltage will only have a limiting effect at high positive and negative slips, but near the limitation, the reactive power capability is very sensitive to small changes in the slip. Copyright © 2007 John Wiley & Sons, Ltd.     

Propagation speed of tribrachial (triple) flame of propane in laminar jets under normal and micro gravity conditions

The propagation speed of tribrachial (triple) flames in laminar propane jets has been investigated experimentally under normal and micro gravity conditions. We found in the present experiment that the displacement speed varied nonlinearly with axial distance because the flow velocity along the stoichiometric contour was comparable to the propagation speed of tribrachial flame. Approximate solutions for the velocity and concentration accounting density difference and virtual origins have been used in determining the propagation speed of tribrachial flame and the concentration field was validated from the measurement of Raman scattering. Under the microgravity condition, the results showed that the propagation speed of tribrachial flame decreased with the mixture fraction gradient, in agreement with previous studies. The limiting maximum propagation speed under the microgravity condition is in good agreement with the theoretical prediction, ie, the ratio of maximum propagation speed to the stoichiometric laminar burning velocity is proportional to the square root of the density ratio of unburned to burnt mixture.     

A stochastic Markov chain model for simulating wind speed time series at Tangiers, Morocco

Time series of then years of Hourly Average Wind Speed, HAWS, data from Tangiers station are analysed on a statistical basis by applying the Markovian process. The limiting behaviour of the Markov chain is then examined and compared to the histogram of observed wind speed. It was found that a 12×12 transition probability matrix was necessary to generate an acceptable synthetic time series. The manner in which the Markovian model can be used to generate wind speed time series are also described.Using the transition probability matrix developed from the real wind data, the synthetic wind speed time series are generated. The comparison between the real wind speed and the synthetic one shows that the statistical characteristics of wind speed are faithfully reproduced. The synthetic HAWS may be utilised as input data for any wind energy system.     

Study on the extension of lean operation limit through hydrogen enrichment in a natural gas spark-ignition engine

An experimental study aimed at investigating the extension of lean operation limit through hydrogen addition in a SI engine was conducted on a six-cylinder throttle body injection natural gas engine. Four levels of hydrogen enhancement were used for comparison purposes: 0%, 10%, 30% and 50% by volume. The effects of various engine operating conditions on engine's lean burn capability were also examined. Test results were then analyzed from a combustion point of view. The results show that engine's lean operation limit could be extended through adding hydrogen and increasing load level (intake manifold pressure). Effect of engine speed on lean operation limit is smaller. At low load level increase in engine speed is beneficial to extending lean operation limit but this is not true at high load level. The effects of engine speed are even weaker when the engine is switched to hydrogen enriched fuelling. Spark timing also influences on lean operation limit and both over-retarded and over-advanced spark timing are not advisable. It is also observed there existed a limiting value imposed on spark-90% MFB burn duration if lean operation limit is not to be exceeded and interestingly, this limiting value was independent on hydrogen enhancement level and engine operating conditions examined in this study.     

低浓度CTAC减阻流体流动性能试验研究

通过对CTAC溶液的减阻性能的测量,得到了CTAC溶液的减阻性能随伴随盐浓度变化的特性。研究结果表明,即使对同种减阻方式,减阻也存在极限和优选。同时,应用激光相位多普勒测速仪进行减阻流体的湍流特性试验研究,得到了50种工况下流体的速度脉动曲线。研究还发现,减阻流体的横向和轴向速度脉动及雷诺应力明显小于牛顿流体;减阻流体的轴向和横向速度脉动之间的关联被明显抑制。     

A mass transfer study of the electropolishing of metals in mechanically agitated vessels

Rates of electropolishing of vertical copper plates in H₃PO₄ were studied in a rectangular cell stirred by 4 blade 45° pitched turbine. Variables studied were impeller rotating speed, plate height and H₃PO₄ concentration. The limiting current density at which polishing takes place was found to increase with impeller rotation speed to the power of 0.44, increasing the plate height (L) was found to decrease the limiting current density (I) according to the equation: I = a L^−0.24. The data were correlated under different conditions by the dimensionless equation Sh = 2.5 Sc^0.33 Re^0.44 (L/d_e)^−0.24     

WAVE PATTERN PRODUCED BY A HEAT SOURCE MOVING WITH CONSTANT VELOCITY ON THE TOP OF AN INFINITE PLATE

Within the framework of linear, isotropic elasticity theory the wave pattern produced by a heat source moving with constant velocity on the top of an infinite plate is computed. Both the transient effects associated with the initial conditions and the damping of the waves are neglected. If the travel speed of the heat source is smaller than the velocity of the surface waves, dispersive flexural waves will be excited. The frequency of these waves is proportional to the square of the wave number if the wavelength is much larger than the thickness of the sheet. In this limiting case it is found that the crest of the waves makes an angle of 90 degrees with the travel direction, and this result is independent of the travel speed as long as the parabolic approximation remains valid for the dispersion relation of flexural waves.     

船用单体泵柴油机控制系统HiL测试与试验验证

以某型电控单体泵柴油机控制系统为例,采用船用柴油机专用的HiL(硬件在环)系统测试同步信号、转速闭环、排温修正策略及极限工况。测试结果显示:冷起动时间2.4 s;额定工况稳态转速波动率0.31%;突加突减负荷时瞬时调速率小于5%,稳定时间小于4 s;各缸排温不平均率维持在5%左右。HiL系统优化后的控制策略在实际配机试验时的应用效果良好,冷起动时间3.6 s;额定工况稳态转速波动率0.67%;负荷突变时瞬时调速率为2.67%,稳定时间为4.9 s,各缸排温不平均率为7.9%。验证结果表明:主要评价指标均满足柴油机整机性能对控制的需求;HiL测试有效提高了控制策略的稳定性和实际配机效率。