引进科隆公司H27系列金属浮子流量计

我厂独家引进德国科隆(KROHNE)公司技术和设备生产的 H27系列金属浮子流量计,是采用新工艺、新结构和独特的计算方法生产的直通式流量计。因其具有独特的优点和齐全的类型已广泛应用于石油、化工、造纸和冶金等行业的流量自动检测与自动控制系统中。1 特点H27 系列金属浮子流量计具有以下的特点:a.检测、传动部件为全机械结构,长期运行稳定可靠;b.标准化设计,DN15-DN100口径的流量计,设计高度为250mm;c.浮子短行程设计,在任何位置上浮子都不会突出测量管;d.凸轮板线性修正及流量刻度为线性读数;e.利用流量转换计算方法,实现刻度为实际介质操作状态下的流量,免除了操作者进行换算的过程;     

浮子流量计的发展介绍

介绍了目前市场流量计类型及其优势、略势,综合介绍浮子流量计,结合各国金属管浮子流量计发展的不同情况,引出金属管浮子流量计将有更广阔的发展前景、更庞大的应用市场。     

孔板浮子流量计原理分析与实验

浮子流量计具有结构简单、工作可靠、压力损失小、可测低流速介质等优点,广泛应用于流量测量。但经典的锥管浮子流量计的测量精度受锥管加工精度影响较大,所以锥管的加工费用较高。首先对孔板浮子流量计的流量计算公式进行了推导,并和经典锥管浮子流量计流量计算公式进行了比较,发现两者在形式上具有类似性,但还是有区别的。并给出了孔板浮子流量计的实验数据,证实理论分析是正确的。孔板浮子流量计的结构形式是可行的。     

“流量测量方法与仪表选用”讲座：第十三讲 浮子流量计的选用（一）

浮子流量计又称转子流量计,是以浮子在垂直锥形管内随着流量变化而升降,改变它们之间形成的流通环隙面积作流量测量的体积流量仪表.本世纪初即盛行欧洲,取名罗托计(Rotameter);在美国、日本也有称作变而积流量计或面积流量计,实际上本类仪表只是变面积流量计的一种,因占了大部分习惯以变面积流量计称之.浮子流量计是量大而广的产品,80年代中期,日本、西欧、美国的销售金额占流量仪表的11%～17%,1990年我国约占14%;现场装用台数占装用流量仪表的15%～20%.我国产量1990年估计在12～14万台,其中95%以上为玻璃锥管浮子流量计.     

浮子流量传感器线性度的研究

浮子流量传感器中存在的非线性问题是影响浮子流量计测量精度的一个重要因素,为了解决这个问题,作者深入研究了浮子流量传感器的特性,利用最小二乘法拟合数据,分析浮子高度和流量之间的非线性关系.理论和实验研究结果表明,针对目前应用的短管型浮子流量计流量和浮子高度之间存在明显的非线性关系,并且发现在其他条件相同的情况下浮子行程的增加即锥管锥角的减小对浮子流量传感器线性度的改善具有重要的作用.     

核电站浮子流量计的卡涩机理及应对研究

在核电站项目建设的调试及运营期间,调试及运行人员报告部分金属管浮子流量计在运行时存在卡涩情况。为应对浮子流量计卡涩的问题,基于对浮子流量计测量原理的分析,结合现场故障流量计的拆解情况进行卡涩故障的机制推演,完整分析了浮子流量计卡涩故障的环境工况因素和自身结构条件,并得出卡涩故障是管道内未吹扫干净的铁磁性杂质和浮子流量计运行机制共同作用所致的结论。根据故障机制的各作用环节提出了针对性的解决方案。在此基础上,对浮子流量计厂家提出的解决方案进行了分析,并对后续核电项目选型使用金属管浮子流量计提出了避免卡涩故障的具体应对措施。该研究结果可用于指导核电站流量测量方案的制订,对浮子流量计的设计改进和研发方向有启示作用。     

数字式金属浮子流量计

该数字式金属浮子流量计的流量传感器由一个上大下小的锥管和可在锥管中上下移动的内嵌磁钢的浮子构成，浮子随来流速度的变化而改变其在锥管中的浮动位置，通过磁路耦合将浮子的直线位移转换成转换器旋转轴的角位移，再经角位移传感器检测出转轴的旋转角度信号，由智能单元完成流量计算、刻度换算并输出信号。本成果的关键部件（即机电转换单元）为鲁棒性良好的电容式角位移传感器、经CFD仿真实验和变物性实验优化的流量传感器以及可进行流量智能化计算、刻度自动换算的信号处理器，     

SPR生物传感器及其对DNA的检测分析

该数字式金属浮子流量计的流量传感器由一个上大下小的锥管和可在锥管中上下移动的内嵌磁钢的浮子构成，浮子随来流速度的变化而改变其在锥管中的浮动位置，通过磁路耦合将浮子的直线位移转换成转换器旋转轴的角位移，再经角位移传感器检测出转轴的旋转角度信号，由智能单元完成流量计算、刻度换算并输出信号。本成果的关键部件（即机电转换单元）为鲁棒性良好的电容式角位移传感器、经CFD仿真实验和变物性实验优化的流量传感器以及可进行流量智能化计算、刻度自动换算的信号处理器，     

“流量测量方法和仪表选用”讲座 第十四讲 浮子流量计的选用（二）

四、应用概况和选用考虑要点1.应用概况按用途选择合适类型,如只要现场指示,首先考虑价廉的玻璃管浮子流量计,如温度、压力不能胜任则选用就地指示金属管浮子流量计;如需要远传输出作流量控制或总量积算,一般首先选用带电信号输出的金属管浮子流量计;如环境气氛有防爆要求的,则可选用气远传仪表或防爆型电远传仪表.     

电远传浮子流量计非线性的产生及其补偿

就玻璃浮子流量计采用差动变压器检测浮子位移,实现电远传的方法进行了介绍,重点介绍了在这种方法下所产生的非线性利用转换器改变反馈电压而获得补偿。补偿后的精确度可达到2.5%。     

Three dimensional numerical simulations of long-span bridge aerodynamics, using block-iterative coupling and DES

The design of long-span bridges often depends on wind tunnel testing of sectional or full aeroelastic models. Some progress has been made to find a computational alternative to replace these physical tests. In this paper, an innovative computational fluid dynamics (CFD) method is presented, where the fluid-structure interaction (FSI) is solved through a self-developed code combined with an ANSYS-CFX solver. Then an improved CFD method based on block-iterative coupling is also proposed. This method can be readily used for two dimensional (2D) and three dimensional (3D) structure modelling. Detached-Eddy simulation for 3D viscous turbulent incompressible flow is applied to the 3D numerical analysis of bridge deck sections. Firstly, 2D numerical simulations of a thin airfoil demonstrate the accuracy of the present CFD method. Secondly, numerical simulations of a U-shape beam with both 2D and 3D modelling are conducted. The comparisons of aerodynamic force coefficients thus obtained with wind tunnel test results well meet the prediction that 3D CFD simulations are more accurate than 2D CFD simulations. Thirdly, 2D and 3D CFD simulations are performed for two generic bridge deck sections to produce their aerodynamic force coefficients and flutter derivatives. The computed values agree well with the available computational and wind tunnel test results. Once again, this demonstrates the accuracy of the proposed 3D CFD simulations. Finally, the 3D based wake flow vision is captured, which shows another advantage of 3D CFD simulations. All the simulation results demonstrate that the proposed 3D CFD method has good accuracy and significant benefits for aerodynamic analysis and computational FSI studies of long-span bridges and other slender structures.     

流量装置流量稳定性数值仿真评价方法研究

为了提高装置流量稳定性,提出基于计算流体动力学（ CFD）仿真,采用轴向动量数KU、旋流数KV 和不对称数KA ,分析管路不同截面位置的流场速度特征,利用多个截面位置的特征参数变化,评价装置管路的流量稳定性。对新建水装置流量稳定性进行数值仿真分析与实验测试,得出一致性结论。该方法可以在装置设计阶段,对流量稳定性进行评价,从而优化管路结构,提高装置流量稳定性。     

Mesh deformation using radial basis functions for gradient-based aerodynamic shape optimization

Gradient-based aerodynamic shape optimization using computational fluid dynamics (CFD), and time dependent problems in aeroelasticity, that is, coupled calculations between computational structural mechanics (CSM) and CFD, require repeated deformations of the CFD mesh.An interpolation scheme, based on radial basis functions (RBF), is devised in order to propagate the deformations from the boundaries to the interior of the CFD mesh. This method can lower the computational costs due to the deformation of the mesh, in comparison with the usual Laplace smoothing. Moreover, the algorithm is independent of the mesh connectivities. Therefore, structured and unstructured meshes are equally treated as well as hybrid meshes.The application of this interpolation scheme in problems of aerodynamic shape optimization is also carefully investigated. When the optimization is executed by a gradient-based algorithm the cost function is differentiated with respect to the design parameters in order to obtain the gradient. The gradient is most efficiently and accurately calculated by solving a certain adjoint equation derived from the discretized flow equations. The calculation of the gradient, which is detailed in this presentation, involves the Jacobian matrix of the mesh deformation.Finally, we present the results of an optimization of the ONERA M6 wing at transonic speed using the interpolation algorithm. The results are used for comparison with another technique of mesh deformation. The quality of the mesh obtained by the new algorithm, and the interpolation error, are analyzed with respect to the parameters of the interpolation scheme: the type of RBF, the RBF’s shape parameter, and the sets of control points.     

基于CFD仿真的切向涡轮流量传感器结构优化

为降低切向涡轮流量计的测量下限,以25 mm口径机械式热量表为例,利用计算流体动力学（ CFD）仿真软件对传感器内部三维流场进行研究,提出了提高传感器性能的10种结构改进方案,并通过CFD仿真对优化后的传感器性能进行预测,选择出最佳方案。结果表明：结构参数改进后,测量下限由0.07 m3/h降为0.035 m3/h。     

多块网格划分技术在CFD仿真中的应用

为提高CFD分析中网格划分的计算精度、减少计算时间、加速收敛,针对某手机的三维模型,采用稳态不可压缩层流分析,应用结构化网格和有限体积法进行计算区域和控制方程的离散.对模型设定边界条件并划分3种不同网格形式,比较可知多块网格划分不仅改善原有网格质量,而且能减少模拟计算时间,提高计算精度.     

基于新型智能探头的大气数据系统算法研究

开展了基于一种新型半圆柱形探头的大气数据系统算法研究工作。通过计算流体力学(CFD)软件计算获得了半圆柱形探头本体和探头所在处的局部流场信息,建立了该种大气数据系统的气动模型和系统算法模型,并通过仿真验证了算法模型的精度。该项研究工作对大气数据系统及大气数据系统传感器的设计开发具有较高的借鉴和参考价值。     

反应堆流场分析的数值模拟

运用CFD分析工具对反应堆内的流场分布进行数值模拟,给出反应堆燃料组件入口处流场的速度和流量分配情况.通过对计算结果的比较分析,对核电厂反应堆内的流动特性有比较全面的了解,从而为反应堆堆内构件的设计和优化提供分析依据.结果表明反应堆内流场采用CFD技术进行模拟计算是可行的.     

基于CFD的集装箱船阻力性能优化

基于CFD方法实现船体型线的自动优化。应用船型参数化建模方法分析特征参数,提取设计变量,以兴波阻力最小为目标,分别采用Sobol算法和Tsearch算法实现船体型线的自动优化。将上述方法应用于5 100 TEU集装箱船的型线自动优化,运用Shipflow软件进行CFD数值计算。评估结果表明优化船型在弗劳德数Fr=0.26时总阻力减少3.62%,说明该方法可行。     

An alternative to CFD: piecewise linear models for frequency spectra of flow induced drag in hard disk drives

A method is proposed to estimate the flow-induced drag on the actuator arm inside a hard disk drive. Typically, drag forces and moments on the actuator are computed as part of a computational fluid dynamics (CFD) solution of the flow field in the entire drive. Unidirectional coupling from the flow to the structure is then imposed to determine the structural response of the arm to the flow induced forcing. The methodology proposed here aims to reduce the simulation time associated with the flow calculations by directly estimating the forcing functions. The approach involves fitting a piecewise linear model (PLM) to the forcing frequency spectrum and interpolating or extrapolating the model to provide estimates of the spectrum at different points in the parameter space. A simple guideline for the formulation of such models is the conservation of energy between the CFD and PLM spectrum. Numerical experiments show that the linear models predict the behavior of arm to within 3% accuracy of the full CFD solution. The proposed technique is applied to two parameters: the disk RPM and the radial position of the arm. Clear trends are manifested for both parameters, making it possible to use this method to estimate forcing functions for a range of disk speeds and radial positions of the arm. This technique opens up the possibility of flow related design or optimization, which was previously thought to be prohibitively expensive.     

现场校准气体转子流量计研究

气体转子流量计广泛应用于各行业中气体流量的测量,其准确度关系到生产过程的安全和产品质量,因此需要对现场的转子流量计进行校准。文章就使用标准表法校准过程中碰到的一些问题进行一些讨论。