流固耦合作用对离心泵内部流场影响的数值计算

采用双向同步求解的方法对离心泵内流场和叶轮结构响应进行联合求解,研究了叶轮流固耦合作用对离心泵内部流场的影响.流场模拟基于Reynolds时均化N-S方程和标准k-ε两方程湍流模型,采用多重坐标系法;结构响应基于弹性体结构动力学方程.并将计算所得的流道网格变形、流场静压和速度的分布以及径向力等结果与非流固耦合计算的流场进行对比分析.分析结果表明,流固耦合作用使得流体和固体区域计算网格发生微小变形,这不仅会改变流体对固体载荷的分布,而且会影响结构对流体的做功作用,从而影响流场的分布;叶片相对隔舌不同位置时,叶轮出口处和蜗壳流道内流场的静压分布变化趋势不同;流场速度变化主要出现在叶片和叶轮出口附近;各时间点上径向力的大小和方向变化较明显.     

基于CFD的离心泵轴向力计算与试验

离心泵特别是高压多级泵的设计中,轴向力的预测是一个关键的问题.现有的2种轴向力预测方法,试验测量耗费时间和财力,而采用经验公式计算,其精度及适用性又较差.本文以CFD技术为基础,对一台井用潜水泵内部流场进行数值模拟,得到泵轴轴端及叶轮表面的压力分布,从而预测出泵的轴向力.对泵样机进行轴向力试验,得到其全工况下的轴向力分布.比较泵主要工况下预测值与试验值,结果较为一致,且预测值最大误差小于10%.     

Influence of Backfill Air Gap on Soil Temperature Recovery in Ground coupled Heat Pumps

Air gap may easily emerge in the progress of backfill in ground heat exchange due to field operation problems. The single U tube three dimensional numerical heat transfer model is set up and there are 3 kinds of backfill air gap assumptions for computational analysis, which are the most common situations in practical projects. Different air gap situations will have considerable effects on soil heat transfer, especially the factor of soil temperature recovery performance, which is investigated in this research, and there is practical project operating data for the comparison confirmation with the theoretical calculation results in inlet and outlet water temperatures. It can be concluded that the backfill air gap will increase the soil average excess temperature in the period of recovery inside the place where the air gap is, and degrade the heat transfer performance of the ground heat exchange.     

水泵机组的振动分析及故障诊断

采用两个磁电式速度传感器测定水泵机组的垂直和水平方向的振动，并对数据进行时域、幅值域、频域、相关和倒谱分析。结果表明，水泵机组电动机旋转引起的振动，通过联轴器传递给水泵，使水泵靠近电动机轴端的轴振动和加剧而造成磨损，进水口的振动大于出水口，机组都存在着高频电磁噪声。本文还提出了减少水机组振动的一些措施。     

Theoretical analysis of a tri polar parallel gear pump

Common gear pumps have numerous shortcomings, including poor flow quality, high unbalanced radial force, imbalanced “balanced compound gear pumps” with complex structure, many leakage points, high manufacturing and assembling precision, high cost, and difficulty using in industrial applications. This paper proposed a new design scheme of a parallel gear pump with three sub structures. Based on the design model, theoretical analysis of structural principles, power density, radial force, flow characteristics, and flow fluctuating were carried out. The result shows the new pump design has the advantages of small axial size, high power density, the initiative gear balanced the gear radial force, and decreased the radial force of the driven gear. By selecting suitable numbers of teeth, it can reduce flow pulsation effectively and improve flow quality.     

离心泵流量—扬程曲线特性研究

研究工业用离心泵的流量－扬程曲线对泵运转稳定性、运转特性和适用场合的影响，提出驼峰曲线泵稳定工况的判据及泵和叶轮形状对驼峰状的影响，对于泵的设计、制造和合理使用均具有实际的意义．     

探针测定大型水泵流量研究

用 5孔探针测定大型水泵流量 ,确定了测量断面和测点布置 ,根据断面轴向流速分布积分求得流量。着重研究了测量方法、影响测流精度的因素和提高精度的措施。本方法已在江苏省 5座大型泵站的 8台机组现场实测中成功应用 ,结果表明该方法设备简单、施测方便、工作量小、易于实现 ,测量精度小于 2 % ,可以推广应用。     

轴向柱塞泵配流副润滑特性的数值分析

设计了轴向柱塞泵配流副的润滑特性试验系统 ,描述了润滑结构与特性试验系统的组成和功能。建立了配流副润滑膜形成的数学模型 ,该数学模型用于描述配流副间润滑膜的运动变化规律和工作介质在阻尼槽、压力平衡油槽中的压力、流量特性及分布规律。对不同工况下的配流副润滑膜的形成进行仿真分析 ,结果表明在其他工况不变时 ,润滑膜厚度随压力和温度的增加而减小。当转速达到 30 0 0 r/m in,盲孔个数为 6时 ,盲孔包角应选为 12°,或者盲孔个数为 12 ,盲孔包角选为 15°     

基于最小二乘支持向量机的泵性能分析

泵的性能曲线是泵选型、优化调度和泵站运行的重要依据,通常该曲线均是通过试验或是根据试验数据和性能图表上的数据进行曲线拟合而获得,但这些方法复杂昂贵,而且拟合精度不高。针对以上方法的缺点,提出了一种基于交叉验证最优参数选择的最小二乘支持向量机（LSSVM）泵性能预测方法。通过最小二乘支持向量机（LSSVM）学习算法网络的设计和构建,并应用网络搜索－交叉验证的方法对支持向量机参数进行优化选择,模拟得到复杂和非线性很强的泵的性能曲线,经优化模型输出值和试验值、同多项式拟合值以及径向基神经网络误差的比较,交叉验证最优参数选择的最小二乘支持向量机具有优良的非线性建模能力和泛化能力,在有限学习样本条件下仍获得了很高的精度,平均相对误差为0.02378%,为泵的性能分析提供了一种简便可行的智能方法。     

Analysis of the Temperature Limit of Dynamic Water Intake of Open loop Surface Water Source Heat Pump Systems

Energy consumption of water intake is one of the key factors for energy saving in the application of the open loop surface water heat pump system. An energy efficiency ratio coupling model for open loop surface water source heat pump systems was established on the basis of the energy consumption model for the water intake and the heat pump units. According to energy saving rate and regulation of energy consumption of water intake, dynamic temperature limits of water intake in different water supply temperature of cooling tower and different pump head were proposed so as to find a calculation method of temperature limits of water intake of open loop surface water heat pumps. Moreover, the energy saving rate of surface water source heat pump systems compared with traditional air conditioning systems under various condition was also calculated.