不同结构湍流抑制器对中间包钢液流动的影响

通过建立1∶3的水力学模型,研究了不同结构湍流抑制器对中间包流体流动特性的影响。实验得出:湍流控制器的类型对注流区的液面波动有明显影响。8边形有孔无檐湍流抑制器造成了注流区2个直径120 mm渣眼,方形有檐湍流抑制器方案注流区无渣眼。几种湍流控制器对中间包流场有一定的改善作用,明显增加了中间包的最小停留时间,最大增加幅度为97%。平均停留时间和最小停留时间相差较小,增加幅度分别在4.2%～7.4%和21.3%～29.9%。     

轴质量对用液体油膜轴承支承转子动特性的影响

本文研究了轴质量对支承于液体油膜轴承上的转子的影响.转子假定是位于弹性轴中部的薄盘,它考虑非零弹性轴质量由液体油膜轴承支承.该径向轴承假定为短简易型,用纵向的和相互作用的刚度及阻尼系数表示,这些系数与系统的角速度有关.假定转于由一电机加速,假定电机速度由一两阶传递函数控制.仿真结果表示质量比的小值,它由轴质量对盘质量比...     

线切割单、多晶硅机床砂浆液调配的研究

线切割机对硅片切割能力的强弱,与砂浆的粘度有着不可分割的关系。而砂浆的粘度又取决于硅片切割液的粘度、硅片切割液与碳化硅微粉的适配性、硅片切割液与碳化硅微粉的配比比例、砂浆密度等。只有达到机器要求标准的砂浆粘度,才能在切割过程中提高切割效率和成品率。     

重油催化裂化余热锅炉节能技术改造

为了进一步回收烟气余热,对克拉玛依石化分公司800kt/a重油催化裂化装置烟气余热利用进行改造,通过拆除低压余热锅炉和中压余热锅炉,新建一座余热锅炉,采用新的节能技术,使排烟温度由190℃降到164℃,节能效果明显。     

四角切向燃烧锅炉煤粉射流逆向稳燃技术的研究开发

本文首次提出并分析了四角切向燃烧锅炉煤粉射流逆向稳燃技术的设计思想。根据炉内三维湍流流场的数值模拟，优化设计了本项技术应用于焦作电厂Ｎｏ．３炉的燃烧器改造方案。计算结果及现场应用证实，采用煤粉射流逆向稳燃技术能够大幅度延长一次风射流中煤粉颗粒在着火初期的停留时间，改善煤粉气流的着火条件，同时能够有效地削弱炉膛出口气流的残余旋转，从而减轻烟温偏差，并能改变煤粉颗粒的切圆运动轨迹，从而缓解了炉膛燃烧器区域水冷壁的结渣与高温腐蚀。     

锌电解槽内电解液流动现象的水力学和数值模拟

以云南驰宏锌锗公司的锌电解槽为基础,根据相似原理制作了相应的水模型,对其内部的流动现象进行了研究;同时,利用商业软件FLUENT对锌电解槽的内部流场进行数值模拟。结果表明:数值模拟建模时采用四边形网格得到的计算结果与水力学模拟的结果相吻合,能够较真实地反映锌电解槽的内部流场。还对不同实际工况下锌电解槽内的流场进行了研究,并提出相关建议,为进一步改善和优化电解槽结构、扩大电解槽规模提供理论依据。     

Experimental and numerical study on the orthogonal and oblique impact on water filled pipes

A 300 mm long piece of copper (ASTM B280) pipe with an outer diameter of 35 mm and 0.7 mm wall thickness was subjected to a rigid steel pipe impact under a drop weight loading configuration where the pipe was simply supported at its ends. Differences in deformation features for a pipe filled with water and an empty pipe were investigated for two configurations namely orthogonal and oblique impact. Compared to orthogonal pipe impact the oblique pipe impact has not been reported in the literature. It is hoped that current work would serve as a first step in this direction. Finite Element Method coupled with Smooth Particle Hydrodynamics (SPH) available in LS-DYNA was used to simulate the empty and water filled pipe impacts under orthogonal and oblique configurations respectively. Fluid structure interaction (FSI) during the water filled pipe impact was successfully modeled using SPH which is a simple method for predicting the short duration FSI events. Experimental results of the effect of varying D/T ratio on the empty and water filled pipes have been reported.     

Development of a Micro Temperature Sensor and 3D Temperature Analysis for a Proton Exchange Membrane Fuel Cell

This study examines the development of micro in situ sensors and analyzed the through‐plane temperature of a fuel cell. Temperature sensing inside a fuel cell is important in fuel cell diagnosis and analysis. Temperature sensors must be adequately small, so that fuel cell performance is maintained and the temperature anywhere inside the cell can be flexibly measured. In this study, a temperature sensor based on a micro‐electromechanical system (MEMS) is designed and fabricated to achieve these objectives. The micro temperature sensor was installed inside a cell to measure through‐plane temperature. The current and voltage of the fuel cell with the micro temperature sensor were measured and compared with those of a fuel cell without the sensor to analyze the effect of the sensor on fuel cell performance. The developed temperature sensor is of resistance temperature detector (RTD) type, with a flexible substrate of polyimide, high sensitivity, and easy installation characteristics. After calibration of the sensors, three sensors were inserted into the cell to measure the through‐plane temperature, and the polarization curve of the cell with and without the micro sensor was compared. Finally, a 3D computational fluid dynamics (CFD) model of a fuel cell was developed and analyzed by comparison of the measured temperature results to determine the accuracy of the model.     

液力偶合器叶轮强度分析及试验验证

通过分析给出了液力偶合器叶轮载荷的数学模型,并利用该载荷模型对某型液力偶合器叶轮进行整体有限元强度分析,建立了该型号偶合器叶轮强度测试试验台,采用应变片对泵轮叶片指定位置强度进行测试。结果表明,利用理论分析建立的载荷模型对叶片进行有限元分析的结果与叶片实际测试结果较吻合,为该系列产品的设计与强度分析提供了依据。     

高压电机内部流体场计算与分析

通过有限元分析软件采用场路结合的方法对电机内部流体场进行分块计算和分析,得出了气流在电机定子通风道内的分布情况,通过改变定子通风槽钢位置来改变气流走向及改变转子通风道上的通风槽钢分布情况,从而优化出更加合理的通风结构来提高电机的换热,降低电机温升.