某电厂烟风系统风机节能分析

电站锅炉烟风系统的电耗占电厂用电的三分之一左右,降低烟风系统能耗,对提高锅炉运行经济性具有重要意义。以某电厂1号机组电站锅炉的烟风系统为研究对象,通过对机组的烟风系统流量、烟风系统阻力、风机运行效率等进行分析,通过计算各个因素对风机能耗影响量,得到风机能耗损失分布及主要原因,并提出切实可行的节能措施,以及当前条件下的风机耗电率目标值。     

风机的喘振及预防

一、简况在泵与风机的运行过程中，当泵（风机）的出口流量小到一空数值时，有时就会产生压力脉动，流量在较大的范围内波动，并伴有噪声和振动，使机组无法连续运行，这即为喘振现象。某厂废水循环冷却处理工程工艺流程如图一所示。该系统的冷却风机并联运行。在风机运行期间，设备剧烈振动，叶轮相继频繁飞出，先后曾调换叶轮17套，对风机也作了一些改进，但仍不能从根本上解决问题，影响了生产，故提出原因分析与技术改造。二、原因该系统有多台风机的关联运行，其运行性能如图2所示。图中1、2、3为同性能风机的性能曲线，并联工作时的曲…     

大型循环流化床锅炉高压流化风系统设计优化

为改善多台并联高压流化风机的运行条件,通过数值模拟和工程应用,对传统式和平行式高压流化风管的流场情况进行分析研究,得出后者可以改善风机运行工况的结论.该成果可以推广应用到其它类似的锅炉岛烟风煤系统.     

电站大型风机的选择

该简要介绍了电站锅炉配套的三大风机性能及运行方面情况,以及脱硫风机的配置,供设计人员比供参考。     

基于LSTM神经网络与贝叶斯优化的电站风机故障预警

风机持续健康稳定运行是电站机组安全性与经济性的重要保障,故障预警技术对于提高风机运行可靠性和降低维护成本尤为重要。为此,本文提出一种基于长短期记忆(Long short-term memory,LSTM)神经网络与贝叶斯优化算法的早期故障预警方法,充分挖掘电站风机正常运行数据,采用LSTM网络挖掘多种参数的关联特性及历史数据的时序特性,建立风机运行状态预测模型。为了提高预测模型的精确度,利用贝叶斯优化算法优化并设定LSTM网络的最佳超参数组合。考虑模型预测偏离度的非平稳性和多极值特点,引入广义极值理论从正常运行工况中确定报警阈值,以实现设备的早期故障预警。最后,将所提出的算法应用于某燃煤电站引风机故障预警中。结果表明：贝叶斯优化算法优化后的LSTM神经网络不仅可以精确表征风机在正常状态下运行行为,同时能够准确地获取风机的故障信息,从而能够在故障发生前4 h发现异常,实现故障预警。     

300MW及以上火电机组风机造型与节能分析

大型电站锅炉配套风机选择恰当与否直接影响到电厂运行的经济性与可靠性。在工程设计中选择适合于本机组的合适风机机型，对电厂运行的经济高效、节约能源、安全可靠性等方面将起到十分重要的作用。     

脱硫增压风机的选型配置设计研究

本文通过对电站常用三种风机的结构性能以及变负荷运行特点的比较，选择出适合于脱硫装置应用的风机类型，对脱硫系统中脱硫风机不同的布置方案进行了比较，并针对不同等级机组脱硫装置中增压风机的配置形式进行综合分析，提出相应的优化方案。     

电站风机故障智能预警技术的应用研究

针对电站风机状态监测和故障预警问题,提出了一种基于密度峰聚类的多元状态估计方法。首先,利用密度峰聚类算法对风机正常运行工况下的历史数据进行分析,提取包含设备正常运行特征信息的数据,构建记忆矩阵;然后通过相关性原理分析观测向量与记忆矩阵之间的相似程度,使用多元状态估计技术对该观测向量进行估计。计算估计值与实测值之间的统计残差和相似度,确定风机的运行状态。最后,以南京某电厂一次风机为监测对象进行研究,建立动态故障预警模型,并结合故障实例分析验证。结果表明:该方法能够实时准确预测风机运行状态,提前发现故障征兆,指导设备运行和维护。     

电站离心式风机性能在线监测的研究及其在DCS中的实现

针对风机设计，运行和性能特点，分析了进行电站风机性能监测重要性和必要性，建立了以曲面拟合理论和神经网络拟合为基础的离心式风机性能监测模型，并与DCS结合完成了通风机性能监测，最后通过现场实践进行了验证。     

600MW锅炉一次风系统节能改造试验研究

针对电站锅炉一次风系统运行方式选择的不合理,导致磨煤机入口风量及一次风机电耗存在偏差,进行了一次风系统风量标定和运行方式优化试验,以现场试验的试验结果作为依据,提出了合理的调整方式。现场运行表明,所提出的调整方式能有效的降低风机电耗,提供准确的一次风量,对制粉系统安全运行、保持炉内良好的燃烧工况和提高锅炉效率有重要意义。     

Numerical simulation of heat transfer in a desktop computer with heat-generating components

The heat transfer analysis of considering heat-generating components with different locations of two side-wall fans in a three-dimensional desktop computer was investigated in this paper. Herein, the well-known computational fluid dynamics (CFD) code of PHOENICS was employed to simulate the dissipative heat transfer in a ventilated enclosure. The SIMPLEST algorithm with the hybrid scheme was utilized to simulate these flows. The parameters are focused on the inlet Reynolds number and the locations of two fans on one of the side-wall boards. The calculating results show that the heat transfer efficiency of mode 4 is better than the other three modes due to the directly dissipative heat by forcing fans right on the vicinity of the high heat-generating components. The present findings not only set up a numerical heat transfer analysis of desktop computer but also provide a basis for further simulation of the associated heat transfer for more complicated situations.     

东辛北带沙四段砂砾岩成因及其成藏模式研究

东辛北带古地貌形态具有“三扇两沟”特征,沙四段发育大套近岸水下扇和滑塌浊积扇砂砾岩体。沉积相带对砂砾岩体储集物性具有重要的控制作用：扇中亚相物性最好,发育中孔中低渗储层;扇缘亚相、滑塌浊积砂砾岩次之,为中孔低渗储层：扇根亚相物性最差,属于低孔低-特低渗储层。近岸水下扇砂砾岩体成藏条件较好,油气藏产量较高;滑塌浊积砂砾岩体由于物性较差,故油气藏含油气充满度较低,含水较高。     

两种型号空冷器选用问题的分析

以某炼厂MTBE项目空冷器设计选型为依据,通过计算换热面积,分析风机使用效率、换热能力、运行寿命、维护、投资,比较常用的铝翅片圆管空冷器和钢制矩形翅片椭圆管空冷器的优劣,为石化装置的空冷器选型提供借鉴。     

Improved cooling performance of large motors using fans

This paper studies the cooling performance by axial fans with forward-swept and inclined blades and a structure with low ventilation resistance for large-capacity open-type motors. The ventilation resistance of axial fans for motors is much greater than that of common fans for creating draughts. Flow separates remarkably on the blades' surfaces and fluid noise is large. We reduced the ventilation resistance inside an electric motor and adopted axial fans with forward-swept and inclined blades. We confirmed by wind tunnel experiment that the flow rate with this combination increases remarkably compared with the conventional ventilation structure and axial fans. Numerical fluid analysis was performed on the flow around the blade at this flow rate. It was confirmed that no flow separation appeared for the air flow along the blade surfaces. This was also observed in a flow visualization experiment. Furthermore, an actual motor with both the low-ventilation-resistance structure and axial fans with forward-swept and inclined blades showed that the flow rate of cooling air increased by 80% compared with that of conventional machines, and the average temperature rise of stator windings decreased by 30%. Thus, the cooling performance was greatly improved.     

仿生轴流风机气动噪声特性的实验研究

针对轴流风机工作时产生的气动噪声问题,运用仿生学原理对某轴流风机叶轮进行了仿生改型设计,分别得到了尾缘锯齿式单结构仿生叶轮的轴流风机和前缘波齿、尾缘锯齿及表面脊状三结构耦合仿生叶轮的轴流风机。对两类风机以及原型风机进行了气动与噪声实验,获得了风机的气动性能与辐射噪声的频谱特性。测试结果表明：两类仿生风机的全压在全流量范围内均有不同程度的下降,最高下降达27%,但尾缘锯齿风机可以提高中小流量工况下的效率,而三结构耦合仿生风机效率低于原型风机;两类仿生风机产生的辐射噪声A声级均低于原型光滑叶轮风机,且尾缘锯齿风机降噪效果优于耦合仿生风机,并且比A声级最大降噪值为1.58 dB;尾缘锯齿沿展向的分布长度越长,效率越高,降噪效果也越佳。     

Heat transfer by a piezoelectric fan on a flat surface subject to the influence of horizontal/vertical arrangement

This study presents an experimental work concerning the thermal performance of piezoelectric fans. A total of six piezoelectric fans with various blade geometries are made and tested. The influence of geometric parameters, including the horizontal/vertical arrangement, and location of the piezofan, on the performance of piezofans is examined. It is found that the heat transfer augmentation of the piezofan comes from the entrained airflow during each oscillation cycle and the jet-like air stream at the fan tip, yet these two modes are of the same order of magnitude. The heat transfer performance for vertical arrangement shows a symmetrical distribution and peaks at the center region whereas the horizontal arrangement possesses an asymmetrical distribution and shows an early peak at x/L = 0.25. It is also found that the heat transfer performance for horizontal arrangement is not necessarily lower than that of vertical one. Based on the dimensionless analysis to the test results for the all six fans, a correlation applicable for x/L = 0 is proposed. The mean deviation is 4.8% that can well describe the influence of geometrical parameters.     

Aero-Acoustics of Modern Transonic Fans—— Fan Noise Reduction from Its Sources

The noise of aerodynamics nature from modern transonic fan is examined from its sources with the perspective of noise reduction through aero-acoustics design using advanced Computational Fluid Dynamics (CFD) tools. In particular the problems associated with the forward propagating noise in the front is addressed. It is identified that the shock wave spillage from the leading edge near the fan tip is the main source of the tone noise. Two different approaches have been studied to reduce the forward arc tone noise and two state-of-art transonic fans are designed using the strategies developed. The following rig tests show that while the fans exhibit other noise problems, the primary goals of noise reduction have been achieved through both fans and the novel noise reduction concept vindicated.     

Aero—Acoustics of Modern Transonic Fans—Fan Noise Reduction from Its Sources

The noise of aerodynamics nature from modern transonic fan is examined from its sources with the perspective of noise reduction through aero-acoustics design using advanced Computational Fluid Dynamics (CFD) tools. In particular the problems associated with the forward propagating noise in the front is addressed. It is identified that the shock wave spillage from the leading edge near the fan tip is the main source of the tone noise. Two different approaches have been studied to reduce the forward arc tone noise and two state-of-art transonic fans are designed using the strategies developed. The following rig tests show that while the fans exhibit other noise problems, the primary goals of noise reduction have been achieved through both fans and the novel noise reduction concept vindicated.     

Performance research and optimization on the fan test system based on experiment

To investigate the fan performance of air conditioning system, two different configuration fan test systems are designed. All scale simulation of the two systems provide the basis for design and improvement of air conditioning system fans to improve the internal flow, increase air volume, and reduce the noise. The conclusion that disturbance on flow of nuzzle outlet is the main sources of measurement error about 5% can be proved by the comparative analysis of the results between computation and experiment. Through Optimization Design of Partial Structure they all meet the industry standard, measurement error less than 1.5%.     

Profile Scaling of Miniature Centrifugal Fans

This paper addresses issues that relate to downscaling the height of centrifugal fans for application in low profile technologies, such as the cooling of portable power electronics. The parameters studied include flow rate, pressure rise, and power consumption characteristics. The former two of these are measured using a fan characterization rig and the latter by directly measuring the power supplied to the fan. These are studied for fan diameters ranging from 15 to 30 mm with numerous profile heights between 0.3 mm and 15 mm. It is found that all of the phenomena encountered are best described in terms of fan aspect ratio. The results show that the conventional scaling laws cannot be accurately applied when blade profile alone is scaled. Indeed, the only parameter reasonably well predicted was the pressure rise attainable, but that was only accurate for fan aspect ratios greater than 0.17. Below this, the pressure rise generated reduces logarithmically toward zero. The study also reveals that no advantage is gained by using fans of aspect ratio greater than 0.3, as the maximum flow rate attainable decreases slightly above this. Overall, the scaling phenomena reported herein provide invaluable information for the future design of efficient low-profile cooling solutions that are to incorporate such fans.