Development of a microwave-type densimeter for slush hydrogen

Slush hydrogen is a two-phase solid–liquid cryogenic fluid consisting of solid hydrogen particles in liquid hydrogen, various applications for which are anticipated, including fuel for reusable space shuttles. The authors of the current study have measured the density of slush hydrogen by using the phase shift that takes place when microwaves are propagated through slush hydrogen, i.e., using the change in the specific dielectric constant. This new technique, unlike the conventional method using a waveguide and horn antenna, features a coaxial cable and patch antenna that can be used at cryogenic temperatures, leading to the development of a slush hydrogen densimeter with a high accuracy of within ±0.5%.     

Development of density and mass flow rate measurement technologies for slush hydrogen

Slush hydrogen is a two-phase solid-liquid cryogenic fluid consisting of solid hydrogen particles in liquid hydrogen. Compared to liquid hydrogen, the density is about 16% greater at a solid mass ratio (solid fraction) of 50%, and the cryogenic heat capacity (enthalpy) is about 18% higher. Various applications are anticipated, including fuel for reusable space shuttles, coolant for cold neutron generation, as well as the transport and storage of hydrogen as a clean energy source. At a solid fraction of within 50%, piped transport can be conducted in the same way as for normal fluids. This paper reports on the slush hydrogen technology in terms of the measurement of the density and the mass flow rate.     

喷嘴流量计与真空滴管流量计的研究

本文对机械真空泵测试中常用的几种流量计进行了讨论,尤其对喷嘴流量计从测量原理上进行了探讨,研究了减少测量误差的措施.着重对滴管流量计量程向小流量方向拓展进行了深入的研究,提出了真空滴管式流量计的设想,完善了结构设置和操作规程,总结了真空滴管式流量计的特点.     

A low-cost noncontact capacitance-type level transducer for a conducting liquid

In this paper, an attempt has been made to design a low-cost noncontact capacitance-type level sensor for a conducting liquid. The sensor is in the form of a uniform circular cylinder made of insulating material like glass, ceramic, plastic, etc. The sensor is connected with the metallic- or nonmetallic-type liquid storage tank, in which the conducting liquid column is taken as one electrode, and a noninductively wound short-circuited outside coil is taken as the other electrode of a variable capacitor. The change in capacitance due to the change of liquid level is measured by a modified linear operational-amplifier-based De' Sauty bridge network with adjustable bridge sensitivity. The bridge output after amplification and rectification may be used to drive a direct current indicator calibrated in level. The studies have been made with high-density polyethylene and glass tube sensors separately in both metallic and nonmetallic storage tanks with tap water as the conducting liquid, and the experimental results of the static characteristics of the level sensors with percentage error from linearity are presented in the paper. These results are found to have good linearity and repeatability within acceptable limits.     

光纤流量计初探

基于光纤的性能优势和光纤传感器的发展前景，文章利用光的强度受流量调制的特性，在传统涡街流量传感器基础上，设计了一种光纤流量计。文章阐述了光纤微弯损耗机理和光纤涡街流量传感器的工作原理，在此基础上提出了光纤涡街流量计系统设计模型，并进行了光纤涡街流量计的稳定性分析。     

液体流量仪表在线校准方法研究

针对液体流量仪表无法离线送检的情况,利用便携式超声流量计准确度高、安装方便的特点,提出一种基于使用中检验思想的液体流量仪表在线校准方法.重点介绍了便携式超声流量计用于液体流量仪表在线校准的技术要求、测量过程和计算方法,并结合实例对该方法进行了分析和验证.最后指出该方法可以为液体流量仪表在线检测提供解决办法,从而为液体流量仪表的在线量值溯源提供了一条可参考的途径.     

Design of a magnetic flowmeter for conductive fluids

The operation of a magnetic flowmeter for conductive fluids is analyzed and the magnetic, and electric fields in it are described as solutions of boundary value problems. Finite-element methods are utilized to solve the problems, and solutions are presented for a variety of flow profiles and inner tube conductivities. The method gives an insight into both the phenomenon involved and the effects of the geometry and the material characteristics on the accuracy and sensitivity of the flowmeter     

Raising the accuracy of a constriction-type flowmeter

Translated from Izmeritel'naya Tekhnika, No. 4, pp. 30–31, April, 1990.     

Calibration of a jet flowmeter on a substitute liquid

Measurement Techniques -     

Synthesis of a simulation model for an electromagnetic flowmeter

The principles of constructing a simulation model for an electromagnetic flowmeter are considered by means of which it is possible to carry out research into the metrological characteristics of instruments. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 38–43, May, 2006.     

Rational choice of the constriction of a flowmeter

The solution of the urgent problem of choosing the type of constriction in flowmeters with a variable pressure drop in industrial instruments for measuring the flow rate of liquids, gases and vapors is considered. Ten criteria are established by which the constriction must be chosen, numerical characteristics are given, and recommendations are made on the rational area of application of each type of constriction. Translated from Izmeritel'naya Tekhnika, No. 9, pp. 33–35, September, 1996     

氮浆在水平圆管中流动压降的数值模拟

氮浆因其密度高、温度低、热容大等特性,可作为高温超导器件等的潜在冷却剂.氮浆的流动特性(尤其是压降)是其在应用中很重要的特征参数.建立了氮浆在水平圆管中流动时压降的二维计算模型,并应用双流体模型、Syamlal-O'Brien曳力模型的CFD模拟方法,对系统中跟流动压降相关的关键因素进行了分析,得出了固氮体积分数、氮浆流速、管道直径和固氮颗粒大小等参数对氮浆液固两相流在水平圆管内流动压降的影响情况.     

A reference model for a flowmeter magnetic field for a computing experiment

A reference model is considered for a magnetic field intended for checking programs and algorithms defining the electromagnetic field in an electromagnetic flowmeter measurement channel. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 39–41, April, 2007.     

Metrological certification of a piston flowmeter for natural gas flows

The results of metrological certification of piston flowmeter RPDU-41pg for natural gas flows are examined.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 28–30, November, 1995.