Characterizing steel tube for hydroforming applications

With the increased use of tubular steel products, especially for hydroforming applications, it is important to be able to predict the performance of tube from sheet tensile tests. In the present study, two aluminum killed draw quality (AKDQ) steels and one high strength low alloy (HSLA) steel were evaluated. Tensile properties and plastic strain ratios were measured on sheet material in the longitudinal and transverse directions. Axial tensile tests were performed on material extracted from production tubes. Material from quasi tubes, which are strip material bent to the same curvature as the tubes but not welded or sized, was also tested. Residual stresses in the production and quasi tube were determined by displacement methods. A hydraulic burst test was performed on the production tubes to simulate a hydroforming operation. Effective strains resulting from tubemaking are calculated for two discrete operations: bending and sizing. For the production tubes, a linear relationship was found between a load factor (strength times thickness) and effective sizing strain. The relationship between load factor and residual stress was also linear. Predictions of the maximum pressure and the strain at instability during a hydraulic burst test are shown to compare favorably with experimental values, based on flat sheet properties and tubemaking strains. The prediction of the yield strength in the tube based on flat sheet properties is shown to be fairly accurate when the effective sizing strain is small compared to the effective bending strain.     

R134a在水平双侧强化管外沸腾换热

对氟里昂R134a在水平单管外的沸腾换热性能进行了试验研究，试验管为4根双侧强化管。在蒸发温度为8℃时比较不同肋型的强化换热性能。结果表明：所研究的强化管均有明显的强化换热作用，E12管的总传热系数略高于其他强化管，其管外沸腾传热系数相对于光管Cooper公式预测值的强化倍率为2.23～2.71，平均值为2.54。由于R22和R134a的物性不同，其管外沸腾传热系数约比R134a高出20%～40%。试验管的沸腾换热强化倍率与制冷剂的关系不明显。     

合成氨二段转化废热锅炉失效分析

综述合成氨二段转化废热锅炉失效历程分析，废热锅炉列管穿孔、管板泄漏及水压试验泄漏的原因，提出解决对策。     

离心机进料技术的改进

通过对离心机进料管线的改进，采用套管式进料管线，浆料泵直接进料的方式，稳定了离心机的电流，防止PVC树脂堵塞管线，达到增强离心机脱水能力的目的。     

二次曲线拟合法波纹管管内传热系数研究

针对波纹传热表面结构复杂难以测量管壁温度的特点,提出了二次曲线拟合法测量波纹管传热系数的方法,研究结构参数对波纹管传热特性的影响规律,为开发和设计结构合理的波纹管换热器提供依据。用W illson拟合曲线分离法,对一定的结构参数波纹管经一次拟合建立传热特性与介质物理性质的准数关系式。在此基础上,对不同的结构波纹管进行实验,并对实验结果进行二次拟合确定结构参数的影响。用该方法得到的波纹管对流传热系数准数关联式,在实验范围内计算误差小于15%。减小侍测侧与非侍测侧传热系数的比值,可进一步提高测量精度。     

钛酸铝陶瓷热电偶保护管的试制

以工业氧化铝和钛白粉为基本原料、滑石为添加剂，采用注浆成型工艺，试制出了钛酸铝陶瓷热电偶保护管。     

水力循环澄清池的技术改造

张掖沙湾水厂的水力循环澄清池是上世纪70年代初建造。由于池深，各部分功能不匹配，动能有效利用率低，排泥不畅,对水量、水质变化适应性差，限制了产水量的提高。经强化絮凝、增设斜管、折板等综合性改造后．单池产水量由原来80m^3／d增加到140m^3／d，药耗降低了15％～20％。改造后仅1年多时间．即可从增产水的效益和节省药耗中收回投资。     

缠绕管件轴压下径向形变和破坏模式的有限元分析与验证

本文采用缠绕工艺制备厚壁碳/环氧复合材料主承力管件,对所制备管件试样进行轴压破坏试验,并采用有限元分析软件ANSYS7.0对试验过程进行模拟分析.分析结果表明轴压管件径向形变最大的位置在距离管件端面20～25mm处,表明该位置容易发生破坏,与实验结果是一致的.     

延迟焦化加热炉辐射管爆管技术分析

通过对大庆石化公司炼油厂延迟焦化装置炉-1辐射管爆管现象进行诊断分析,找出了发生爆管的3个原因,管材质量,炉管内存有未烧净的焦子,加工的原料发生变化,并逐个进行分析,提出了保证加热炉长周期平稳生产的措施。     

倾斜下降管内油气水三相流流型转变的实验研究

对倾斜下降管倾角变化对油气水三相流流型转变的影响进行了研究 ,通过大量实验得到流型图 ,发现倾角对流型转变有重大影响 :倾角增大到 3 0°时 ,增大气流量 ,泡状流已不再转变为间歇流 ,而是分层流 ;倾角变化对环状流和间歇流之间的转变影响显著。得到的界限方程规律与实验现象及流型图符合良好