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电磁流量计具有高精度的特点。但是电磁流量计的励磁频率对液固两相介质的测量具有非常严重的影响,只有选择合适的励磁方式和励磁频率,仪表才能得到满意的测量结果。本文通过对电磁流量计的组成、测量原理、励磁方式进行分析,结合我公司生产的KF20型电磁流量计系统分析了励磁频率对测量精度的影响。 相似文献
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作为一种新型的流量测量仪表,电磁流量计在最近几年里获得了长足的发展,其以自身优良的性能和特点被广泛应用于工业领域中各种导电液体的流量测量,同时在食品、化工以及水处理等行业中各类浆液流量的测量中也有所应用。虽然与其它流量计相比,电磁流量计有着诸多优点,但它也有一定的缺陷,即容易受到外界的干扰。为此,在应用电磁流量计时,必须采取有效的抗干扰措施,这对于确保测量结果的准确性具有非常重要的意义。基于此点,本文就电磁流量计中干扰问题展开探讨。 相似文献
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关于污水处理厂电磁流量计在线检测方法的探讨 总被引:1,自引:0,他引:1
电磁流量计目前大多采用离线检定法,为探知现场使用条件下流量测量的准确性,需对电磁流量计进行在线检测。通过现场试验来说明采用超声波流量计对电磁流量计进行在线检测的可行性,并阐述了提高在线检测准确性的方法和在线检测的应用前景。 相似文献
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电磁流量计是当前我国管道测量的主要工具,得到了广泛应用,想要满足社会发展的客观要求,需要对当前管道式电磁流量计的在线校准要求有一个充分的了解,管道式电磁流量计所具有的测量原理主要是以法拉第电磁感应定律为基础,主要的组成由传感器和转换器,传感器一般会被直接安装到测量的管道上,转换器则是可以通过与传感器的组合连接来构成一体型的电磁流量计,两者间的链接如果是通过屏蔽电缆实现的,就还会被统称为分离型电磁流量计。其在线校准主要是通过电参数法和标准表法来进行的,无论是哪一种校准方式都需要按照地方规范和行业标准来进行,本文对此进行了详细分析,希望能够促进管道式电磁流量计在线校准质量的提升。 相似文献
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从电磁流量计理论出发,建立插入式电磁流量计的物理模型,求出相应的电势、磁势和权函数的分布,并进行了定量计算,分析不同流场下插入式电磁流量计的输出电势差。计算研究表明,如果把电极放置于平均流速点位置,这种流量计可以测得通过管道的流量,电极位置偏差所产生的测量相对误差约为1%~2%。 相似文献
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针对水流量标准装置中横板型稳压罐,基于Navier-Stokes方程建立罐体计算流体动力学仿真模型。使用湍流模型、流体体积函数瞬态模型和有限体积法进行离散,并在近壁区采用标准的壁面函数法进行修正,完成横板型稳压罐内部两相流场的数值模拟。数值结果显示空罐充水流态依次经过无水状态-射流-上壅-漫流-稳定状态,同时形成掺气现象和泡状流;气液体积比1:3情况下,满罐充水流场有固定周期的晃荡现象,上侧形成逆时针转动的漩涡气腔,流场湍流粘度较小,分布较均匀,稳定效果最好。 相似文献
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基于时差法的超声水表在中、大口径的水流量测量中,存在超声波信号易受外界干扰以及小流量的测量重复性较差等问题.针对以上问题,本文设计了具有缩径结构的管路模型.其次,通过CFD数值仿真研究了缩径管路模型在低流速下的流场分布情况.最后对本文设计的双声路超声水表样机进行了相关试验.试验结果表明,本文设计的管路模型有效提高了超声... 相似文献
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为了提高搅拌器的搅拌效率和使用寿命,以管坯内置磁场搅拌器为研究对象,用Sn-3.5%Pb合金代替钢液进行实验和数值模拟,借助Fluent和ANSYS软件研究了搅拌器的结构参数和电磁参数对金属液所受电磁力和流动状况的影响规律.结果表明:相比两相绕组,采用三相绕组的电磁搅拌器能效更高;磁轭结构对搅拌器的作用效果影响显著,为提高金属液所受电磁力应使磁轭的齿部尺寸尽量小些,但若尺寸太小会使磁轭饱和,影响磁轭的使用寿命;电流强度越大则金属液内的流速越大,电流强度与金属液流速呈线性变化,而电流频率与金属液流速呈非线性变化,电流强度对金属液流动的影响要大于电流频率. 相似文献
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Numerical simulations in 3-d for porous media models in soil mechanics are a difficult task for the engineering modelling
as well as for the numerical realization. Here, we present a general numerical scheme for the simulation of two-phase models
in combination with an abstract material model via the stress response with a specialized parallel saddle point solver. Therefore,
we give a brief introduction into the theoretical background of the Theory of Porous Media and constitute a two-phase model
consisting of a porous solid skeleton saturated by a viscous pore-fluid. The material behaviour of the skeleton is assumed
to be elasto-viscoplastic. The governing equations are transfered to a weak formulation suitable for the application of the
finite element method. Introducing an abstract formulation in terms of the stress response, we define a clear interface between
the assembling process and the parallel solver modules. We demonstrate the efficiency of this approach by challenging numerical
experiments realized on the Linux Cluster in Chemnitz.
Received 15 February 2002 / Accepted 12 April 2002 相似文献
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特大口径电磁流量计是一种新型的大口径计量仪表。然而它的实施检定是制约其自身发展的关键因素。本讨论了用标准表法检定特大口径流量计的原理,分析了标准流量计的误差修正,以期找到一种用标准表法检定特大口径电磁流量计的理想方法。 相似文献
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Optimization of a Low-Voltage Load Switch for a Smart Meter Based on a Double Response Surface Model
The existing electric energy meter load switches have issues such as a low electrical life, poor resistance to short-circuit currents, high contact point resistivity and severe heating. Research has thus been conducted on the optimization of the electric energy meter built-in load switch mechanism to establish a double response surface model for the electromagnetic attractive force and reed reaction force. The model introduces a niche fitness sorting strategy and a Gaussian mutation mechanism that are based on the standard particle swarm algorithm and form an improved multi-objective particle swarm optimization algorithm in which the static attractive force is regarded as the optimization objective. The multi-objective optimization of the structural parameters of the electromagnetic system and the reed system was carried out, and the optimization results were applied in the devices’ design and implementation. The new structure improves the electromagnetic suction and reed force at the suction position. And the results from simulation show that the proposed method exceeds that of the back propagation neural network method in achieving the optimization goal and the new structure can effectively improve the performance of meter built-in load switch by avoiding the recoil phenomenon. 相似文献
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Thermal dispersion of heated effluent in a lake near nuclear power plant is analysed. Lake Bathymetry is established by data collection at a pre-planned matrix of sample points in the lake. Three-dimensional geometric model of the lake is developed based on the geometric data collected, using a high accuracy GPS and a dead weight based depth meter at respective sample points of the lake matrix. A turbine type digital flow meter is used to measure the velocities at the intake and blow down points of the lake. Numerical analysis of flow and thermal dispersion is carried out using PLIC-VOF two-phase model with the two-equation k-epsilon model for turbulence closure. Numerical results for varying flow and blow down temperature conditions and wind speed are studied. It is observed that the thermal gradients are steeper in the curved area near the blowdown point. Small increase in main inlet (inlet II) velocity suppresses the dispersion of high-temperature contours significantly. Thermal discharge and dispersed temperature is monitored using temperature sensor mounted floating buoy at various locations in the lake. It is established that the thermal dispersion is influenced by wind velocity and the presence of water hyacinth in the lake. 相似文献