周向前弯轴流风扇转子叶顶泄漏流动研究

以低压轴流风扇3个代表性的周向前弯角(前弯1.27°、8.3°和25°)的叶轮作为研究对象,对三维粘性流场进行了数值计算,并对出口损失进行了试验测量,计算与测量结果能够较好地吻合。结果显示,叶顶泄漏涡的起始位置随着叶片周向前弯角度的增加而沿叶弦后移,逐渐接近叶片后缘,但旋涡的强度并不是一直增大,达到某一前弯角度以后,泄漏涡由于受到叶片尾迹的影响而减弱。由此反映出,较大的前弯角度的叶轮,叶顶区域流动变得更加复杂,同时对上端部损失的影响因素增多,包括了泄漏涡、二次涡、尾迹以及它们之间的相互掺混。     

双回路中冷的柴油机冷却水系统

将用于机车柴油机的双冷却水回路增压空气中间冷却器（中冷器）和常用的单水回路中冷器冷却方式进行了对比,介绍双回路中冷的柴油机冷却水系统对机车、陆用发电机组等利用风扇来冷却柴油机和水的机组的好处,并分析其相应的系统原理。     

Study of unsteady flow simulation of backward impeller with non-uniform casing

The flow characteristics of the centrifugal fans with different blade outlet angles are basically discussed on steady and unsteady simulations for a rectangular casing fan. The blade outlet angles of the impellers are 35° and 25° respectively. The unsteady flow behavior in the passage of the impeller 35° is quite different from that in the steady flow behavior. The large flow separation occurs in the steady flow field and unsteady flow field of the impeller 35°, the flow distribution in the circumferential direction varies remarkably and the flow separation on the blade occurs only at the back region of the fan; but the steady flow behavior in the impeller 25° is almost consistent with the unsteady flow behavior, the flow distribution of the circumferential direction doesn't vary much and the flow separation on the blade hardly occurs. When the circumferential variation of the flow in the impeller is large, the steady flow simulation is not coincident to the unsteady flow simulation.     

锅炉一次风机周期性振动异常原因分析及处理

基于某一次风机的结构和工作原理,针对一次风机主轴承箱运行过程中出现振动趋势随环境温度变化周期性波动的问题进行剖析,采取振动监测、淋水试验、频谱分析等方法进行深入研究,利用排除法找到了一次风机主轴承箱运行过程中振动异常的根本原因。研究结果表明：一次风机混凝土基础被扰动导致混凝土基础整体强度不足,进而引发一次风机主轴承箱运行过程中振动异常并随环境温度变化出现周期性波动。通过对一次风机混凝土基础进行注浆加固,不仅使主轴承箱振动趋势随环境温度变化问题得到明显改善,而且一次风机主轴承箱运行过程中最大振动值由4.3降至2.6 mm/s,振动趋势显著降低并达到标准水平。     

旋转机械信号光电转换发送系统的研究

通过对旋转离心风机叶片表面压力信号测量的应用，介绍了采用光电转换方式将旋转系统内部信号有效可靠地传送到静止系统的实验装置及电路。通过I^2C总线数据传输方式、光电“串行”及“准并行”光电传输方式，实现了对采样数据的发送，并将校验系统运用到该装置中，解决了动静系统的信号可靠高速传输的问题，该测试手段可广泛应用于旋转系统内部流场、压力、振动等的测量。图9参3。     

Numerical and experimental study on aerodynamic performance of small axial flow fan with splitter blades

To improve the aerodynamic performance of small axial flow fan, in this paper the design of a small axial flow fan with splitter blades is studied. The RNG k-ε turbulence model and SIMPLE algorithm were applied to the steady simulation calculation of the flow field, and its result was used as the initial field of the large eddy simulation to calculate the unsteady pressure field. The FW-H noise model was adopted to predict aerodynamic noise in the six monitoring points. Fast Fourier transform algorithm was applied to process the pressure signal. Experiment of noise testing was done to further investigate the aerodynamic noise of fans. And then the results obtained from the numerical simulation and experiment were described and analyzed. The results show that the static characteristics of small axial fan with splitter blades are similar with the prototype fan, and the static characteristics are improved within a certain range of flux. The power spectral density at the six monitoring points of small axial flow fan with splitter blades have decreased to some extent. The experimental results show sound pressure level of new fan has reduced in most frequency bands by comparing with prototype fan. The research results will provide a proof for parameter optimization and noise prediction of small axial flow fans with high performance.     

向心式通风机级的数值模拟及变工况特性研究

以完全气体作为流动工质,设计了单级向心式通风机,并进行了流场模拟和变工况特性研究。首先采用BladeGen构造动叶叶型,并对动叶叶型进行参数化;然后采用数值模拟方法得到流场参数,以级效率为目标函数,以总压比为约束条件,在Workbench平台上对动叶叶型参数进行优化,得到最佳的动叶叶型;在已设计好的动叶基础上,利用单圆弧构造法设计静叶并设置在动叶后面,得到向心式通风机级;最后分析不同流量,不同转速下所设计的向心式通风机级的变工况特性。     

风机转子的振动与临界转速计算分析

某电厂锅炉送风机,多次发生叶片断裂事故,严重影响了电厂生产的正常运行,本文针对风机转子进行了固有频率振型和临界转速计算,根据对计算结果的对比分析,排除了转子结构不合理是造成事故直接原因的假设,避免了电厂对转子结构进行了不必要的改造。     

基于小波变换的离心风机弱失速特征分析

结合实验室4—73Nd8D风机进行了旋转失速试验,将谐波小波变换引入旋转失速的研究,通过对弱失速阶段机壳压力信号的时频分析,确定了弱失速阶段的失速能量间歇现象、频率特征以及在弱失速阶段对调节作用的敏感性,从而说明离心风机的弱失速阶段是一个应该引起运行、维修人员足够重视的重要区域,这也为离心风机旋转失速的深入开展研究莫定了基础。     

工业锅炉引风机电机超载浅析

引风机是工业锅炉重要的辅机之一,其运行的稳定型选型的合理性直接关系到锅炉的安全经济运行。由于用户实际运行状况不同,时常出现引风机的驱动电机电流严重超载现象,严重的甚至引起引风机电机烧毁。