液力偶合器在大型锅炉风机上的节能应用研究

文章介绍了液力偶合器用于调节大型锅炉风机风量的节能原理,分析比较了应用液力偶合器调节风机风量与传统的节流调节风机风量的节能效果,实际应用得出:采用液力偶合器调节风机风量具有显著的节能效果,并能使系统实现自动控制、无级调速、工作稳定等,值得推广.     

电站锅炉给水泵节能改造

介绍了滦河发电厂针对锅炉给水调节门节流损失严重的问题 ,提出了液力偶合器变速调节、电机变频调节、小汽轮机变速驱动三种改造方案 ,通过技术经济性对比 ,确定选用液力偶合器变速调节 ,经济性分析和实际运行效果都表明了中、小型机组采用液力偶合器变速调节锅炉给水泵是经济可行的。     

锅炉引风机采用变速调节技术

锅炉引风机采用液力偶合器进行变速调节，不但取得了较好节能效果，而且延长了电机和引风机的寿命。液力偶合器结构简单、运行可靠、维护量少。经过长期运行实践证明，锅炉引风机采用液力偶合器进行调节是可行的。     

锅炉高压给水泵液力偶合器调速的特性分析

目前,锅炉高压给水泵广泛采用液力偶合器调速来实现流量调节,具有明显的节能效益。 (一) 在叙述叶片泵(或风机)采用液力偶合器传动(以下简称偶合器)调速进行流量调节时,一般都假定其动力特性为M_z∞n_z~2(或N_z∞n_z~8,角标“Z”表示它们是传动     

泵和风机偶合器调速控制系统中可编程序控制器的应用

在泵和风机的液力偶合器调速系统中使用可变函数发生器可以消除因偶合器调节特性的非线性引起的不稳定现象，应用可编程序控制器(PLC)的可变函数发生器可靠性高、操作方便、适用性广。本文就可变函数发生器的PM实际应用进行了分析介绍，同时，简述了现场调试的方法。     

液力偶合器的正确使用和维护

对ＹＯＴＪ４２０型液力偶合器在使用中积累的经验进行综合分析，叙述了使用维护液力偶合器时的一些注意事项；分析了液力偶合器的常见故障及其产生原因，指出了排除故障的方法。     

液偶调速电动给水泵节能改造方案解析——行星齿轮变矩调速器与变频器方案对比

当前火力发电厂锅炉给水泵普遍采用液力偶合器作为调节装置,但是由于液力偶合器的机械结构和调节方式的限制,液力偶合器调节方式存在效率较低和可调范围较小等不足,随着科技发展和技术创新,多种新型调节装置可用于锅炉给水泵调节。介绍了行星齿轮变矩调速器(VORECON)与变频器(VFD)两种新型调节装置的原理、性能、改造方案和费用,通过实际改造案例详细对比了两种方案的改造后实际效果和费用,得出变频器改造方案优于行星齿轮变矩调速器方案的结论。     

液力偶合器在柴燃联合及柴油机并车传动中的应用

本文论述了液力偶合器的工作原理和工作特性，以及各类液力偶合器适用范围，并较全面地介绍了它在舰船动力装置中的应用。     

调速型液力偶合器运行效率计算及节能分析

本文介绍了调速型液力偶合器的特性及与其匹配的电机、工作机的特性;推导出调速型液力偶合器运行效率、损失功率、节约功率的计算公式并确定出极值及极值位置点;绘制了功率与调速比的曲线图及节约功率、损失功率的直观示意图;为调速型液力偶合器的生产单位及使用单位提供节能的理论依据。     

调速型液力偶合器在锅炉送风机上的应用

通过对锅炉送风机运行情况的分析,提出了迭风机加装调速型液力偶合器的改造方案,并分析采用调速型液力偶合器实现送风机变速运行的经济性和安全性,同时举例说明了采用调速型液力偶合器取得的经济和安全效果。     

泵或风机并联运行偶合器同步调速控制方法研究

本文分析了并联运行系统的工作特性,指出了泵或风机非同步运行存在的问题;大功率应用领域采用偶合器调速是一类适宜的调节方式,在分析偶合器调节特性的基础上,给出了一种实用的同步调速控制方法。     

同发矿井综放工作面刮板输送机驱动方案设计

针对同发矿井综采放顶煤工作面前后刮板输送机驱动方式的选型设计,通过变频器、液力偶合器、CST机电软起动和调速型液力偶合器的比较及经济技术和现场实地考察分析,最终确定综放工作面刮板输送机驱动方案设计为变频器一拖二运行方式。     

在线自适应误差模型船速调节器的研究

提高船舶航速和主机负荷的稳定性是船舶运动控制的主要目标之一.以船速为被控量,主机负荷为操作变量,应用活化函数为改进双曲正切函数的自适应神经网络和最陡下降法的非线性优化技术控制策略,建立了船速误差和主机负荷误差的串级自适应控制模型.设计了由计算机、PLC、变频调速电机、伺服电机和离心水泵组成的船速综合控制半实物仿真系统,实现了在不同调速状况下的稳定性控制.结果表明:在系统模型不确定,控制对象大惯性大滞后情况下,自适应误差模型抑制扰动和参数摄动有明显的优势,整个船速控制过程平滑稳定.     

开关磁阻风电制氢动力传动系统机电耦合动力学分析

为揭示开关磁阻风电制氢动力传动系统的机电耦合作用规律,考虑齿轮系统的详细特性和制氢装置非线性物理细节以及发电机电磁特性,建立包含风轮、齿轮传动系统、开关磁阻发电机、制氢装置的开关磁阻风电制氢动力传动系统机电耦合动力学模型,仿真分析变风况下系统的能量流、机电耦合动力学特性以及并联电解槽数量对系统动态特性的影响.结果表明:...     

Combined constant speed control method for a wind generator equipped with hydraulic energy storage

A wind generator equipped with hydraulic energy storage (WG‐HES) uses hydraulic transmission systems instead of gearbox transmissions, thus eliminating high‐power converters and reducing the tower‐top cabin weight. When there is no wind or the wind speed is extremely low, the pressured oil released by accumulators is used to drive a motor to operate at a constant speed, thereby generating constant‐frequency power. However, few studies have examined the constant speed control characteristics for generating electricity using only an accumulator group. In this study, a combined constant speed (CCS) proportional–integral–derivative (PID) control method based on “variable displacement and throttling” is proposed, which includes two closed loops and one regulating loop. First, a simulation model of the CCS PID control method for a variable motor was established in the Simcenter Amesim program. The influence of different PID parameters on the anti‐interference ability of the constant speed control of the motor was analyzed under a given load step. Then, we obtained the range of control parameter values and a set of optimal values. Second, the effectiveness of the CCS control method and the accuracy of the simulation results were verified on a 600‐kW WG‐HES system prototype. The results verified that the CCS control method has good anti‐interference ability and can meet the requirements of constant speed control for a variable motor under the best PID parameters. These results can provide a basis for developing control strategies for WG‐HESs when there is no wind or at low wind speeds.     

基于模糊控制的风电机组独立变桨距控制

在额定风速以上时,通常采用变桨距控制技术调节大型风电机组来稳定其输出功率.由于风力发电系统的数学模型具有高度非线性、多变量、强耦合的特点,风速又具有多变性,因此文章在分析传统的PID变桨距控制技术优缺点的基础上,提出了基于三维模糊自适应PID控制的独立变桨距控制技术,并且引入风速的模糊前馈控制技术.对1 MW风电机组进行仿真,结果表明,在额定风速以上时,该方法不仅能稳定风电机组的输出功率,而且可以减小桨叶的拍打振动.     

Effect of heat transfer on stability and transition characteristics of boundary-layers

Stability and transition problems of two dimensional boundary-layers with heated walls have been studied numerically using the linear stability theory. Incompressible stability equations have been modified to account for the variation of temperature dependent fluid properties across the layer. The equations obtained have been solved with an efficient shoot-search technique. Low speed flows of air and water have been analyzed with a wide range of heat transfer rates. In addition to the mean velocity profile characteristics, variable viscosity and density terms in the stability equations also have considerable influence on the results of the stability and transition analysis.     

A study on the effect of qualitative control coupling variable engine speed on the hydrogen-fueled Wankel rotary engine at wide-open throttle

Hydrogen-fueled Wankel rotary engine, with few available research currently, has excellent power and emission characteristics, however, with lower efficiency. With increasing attention to low-carbon emission, it is of great significance to explore methods to improve the efficiency of hydrogen-fueled Wankel rotary engines. This work aims to study the effect of qualitative control coupling variable engine speeds at the wide-open throttle on the power control. The comparative effect of qualitative control coupling engine speeds from 1000 r/min to 1500 r/min under the wide-open throttle and quantitative control at 1500 r/min on the combustion and emission characteristic of hydrogen-fueled Wankel rotary engine is investigated. The results show that compared with quantitative control, qualitative control coupling variable engine speed can achieve excellent performance. The brake thermal efficiency can be maximally increased by 43.5%, an absolute increase of 6.22%, as well the volumetric efficiency with a maximal 105% improvement. The thermal load and risk of knock can be greatly reduced. Moreover, NO emission also can be reduced by more than an order of magnitude or even by zero. Although there is an increase in cyclic variation, the value is no more than 4%. In addition, qualitative control coupling variable engine speed allows flexible matching of appropriate engine speed and excess air ratio based on the actual requirements of efficiency, stability, durability and emission.     

切出风速下风力机变桨故障叶片气动特性及准静态结构响应分析

为探究大型水平轴风力机达到切出风速停机后变桨故障叶片的气动特性及准静态结构响应,基于计算流体力学方法对NREL 5 MW风力机变桨故障/成功叶片气动侧状态进行分析,并利用双向弱流固耦合及曲屈分析对典型方位角下变桨故障叶片展开研究。结果显示：切出风速下变桨故障叶片挥舞力矩平均值为变桨成功叶片的13.8倍,且前者的流场尾迹更为明显。此外,180°方位角变桨故障叶片较之0°方位角变桨故障叶片应力及叶尖位移分别减小29.8%和32.7%,一阶屈曲因子增加20.2%。