Measurements of Particle Velocity and Concentration for Dilute Swirling Gas-Solid Flow in a Vertical Pipe

Experimental studies concerning the characterization of a dilute swirling gas-solid flow were carried out in a vertical pipe with a height of 12 m and an inner diameter of 80 mm. Polyethylene pellets, with mean diameter of 3.2 mm, were used as test particles. The initial swirl number varied from 0.0 to 0.94, the mean gas velocity varied from 9 to 25 m/s, and the solid-gas ratio varied from 0.2 to 0.7. In this study, the particle velocity and concentration profiles were measured by the photographic image technique for both nonswirling (axial) and swirling gas-solid flows. It was found that the particle velocity of the swirling flow is lower than that of the axial flow in the range of high gas velocity; however, high particle velocity in the former flow can be obtained in the range of low gas velocity. The particle velocity profiles, on the other hand, were found to be nearly uniform in both the swirling and axial flows. The particle concentration profiles in the swirling flow exhibited symmetric distributions with respect to the pipe axis, and a higher particle concentration appeared in the vicinity of the wall located in the acceleration region.

gas-solid two-phase flow particle concentration particle velocity pipeline swirling flow     

速度、压力场对铝液侵蚀模具的影响

为了探明压铸生产过程中熔融铝合金速度、压力场对模具侵蚀过程的影响及其作用机理,本文设计动态侵蚀试验,通过计算流体动力学仿真软件计算旋转试样圆周区域速度场和压力场分布状态,观察试样表面的宏观形貌并利用SEM、EDS作元素微量分析。结果显示:试样前端与尾端区域速度最大,前端与远端之间压力场最大;流体压力场对试样侵蚀的影响属压应力作用,促进原子间的扩散,加快金属间化合物生成的速度,加剧试样表面的侵蚀程度;流体速度场对试样侵蚀的影响属切应力作用,导致生成并附着于试样表面的金属化合物层剥离,造成深坑状的腐蚀形貌。     

Measurements of Creep Internal Stress Based on Constant Strain Rate and Its Application to Engineering

This research is carried out on the basis of Constant Strain Rate （CSR） to measure creep internal stress. Measurements of creep internal stress are conducted on the material test machine by using the CSR method. A mathematical model of creep internal stress is also proposed and its application is presented in this paper.     

基于超声传播时间法的水轮机流量测量不确定度

流量是水轮机绝对效率评价的关键要素,不确定度是评定流量的重要指标。对比了典型的水轮机流量测量方法,针对其中超声传播时间法的不确定度评定问题展开了研究。采用全站仪建立精确的管道三维模型,并通过测量探头与管道的相对位置关系,实现了几何参数的校准,获得了良好的不确定度水平;结合对超声传播时间量和流量积分的合理估计,给出了超大口径流量测量不确定度评定方法,对超大口径流量计不确定度评定提供了有益的补充。     

Measurement of the Component-by-Component Flow Rate of a Gas-Liquid Medium by the Thermal Method

Measurement Techniques - The issue of the measurement of a gas-liquid medium by the mass component-by-component flow rate is examined. A thermal method is proposed for measurement of the...     

表面粗糙度比较样块测量的不确定度分析计算

分析了表面粗糙度比较样块Ra测量结果的不确定度来源并作了举例进行分析计算。     

微槽平板热管的流动分析

通过建立微槽平板热管的数学模型,得到了热管内部毛细流动和传热的数据,分析了热管在多种工况下工作特性的变化规律,考察了汽液界面上的剪切作用对热管传热量的影响,并且进一步在理论上预测了该型热管的毛细和沸腾极限。     

Reliability of Measurements of the Natural Gas Flow Rate and Volume in Gas Distribution Organizations

The proposed new approach to the procedure for measuring the flow rate and volume of gas under standard conditions in gas distribution organizations increases the reliability of the measurements. It is based on identical transformations of the Clapeyron-Mendeveleev equation, with modifications, and takes into account the composition of the natural gas and the recommendations of Federal Law No. 69-FZ (article 19) of March 31, 1999, about natural gas certification by Gosstandart of the Russian Federation. Use of the modified Clapeyron–Mendeleev equation is shown to changes the form of the transformation functions of various primary measuring transducers (turbine, rotary, vortex, ultrasonic, etc.) under the conditions of actual measurements.     

Slender Tactile Sensor for Contour and Roughness Measurements Within Deep and Narrow Holes

A tactile cantilever sensor is described which was designed for quality assurance of high-aspect ratio microcomponents, e.g., spray holes of diesel injector nozzles. It was constructed as an extremely slender silicon cantilever of 1.5–5 mm in length, 30–200 $~mu$m in width, and 25–50 $mu$ m in height comprising a silicon probing tip at its free end. Close to its clamping, a piezoresistive strain gauge was integrated for signal read-out. The novel sensor was designed to be operated at high scanning speeds offering a millimeter scanning range at a micrometer lateral resolution and a ten nanometers vertical resolution. Cross sensitivity versus temperature and ambient light referred to vertical tip deflection was below 10 nm during a tactile measurement, which was performed under typical tactile probing conditions, i.e., temperature and light intensity variations of 1 K and 0.1 mW/cm $^{2}$, respectively. In form and roughness measurements with calibrated standard artifacts as well as with narrow spray holes of advanced diesel injector nozzles, we demonstrated the potential of slender cantilever sensors for high-aspect-ratio micrometrology.      

空调风管系统的现场漏风量测试

新规范GB50 2 4 3- 97实施后 ,要求对风管进行漏风量测试。文章结合大上海时代广场空调安装工程施工交验时的漏风量测试 ,总结了切实可行的现场漏风量测试方法。     

Method for Monitoring the Longitudinal Relaxation Time of Flowing Liquids Over the Entire Range of Flow Rate Measurements

Measurement Techniques - The problems of monitoring the state of flowing liquids used in various branches of industry, power production, and agriculture are examined. Means of monitoring the state...     

中压配电网单相接地故障精确定位研究与应用

随着对中压配电网供电可靠性要求的不断提高,配电网故障点的准确定位显得尤为重要。本文针对配电网单相接地故障将故障定位的理论方法应用于实际现场中。该理论方法可分两步进行,第一步为故障测距,第二步为故障分支。其中故障测距由行波法确定,故障分支由直流定位法进行确定。并在行波法受到限制或失效时,可采用直流定位法进行弥补,这样通过方法的互补性可以提高故障定位的准确性。最后利用现场数据和ATP仿真验证了此综合方法的可行性。     

SiC材料的低速率浅刻蚀工艺研究

对比研究了SiC材料在CF4+O2混合气体中的ICP刻蚀和RIE刻蚀,获得了刻蚀速率、刻蚀表面粗糙度随刻蚀功率、偏置功率、工作真空、氧含量等工艺条件的变化规律,研究结果表明,通过牺牲一定的刻蚀速率可以获得原子量级的刻蚀表面粗糙度,能够满足SiC微波功率器件研制的要求.     

高精度大流量气体流量标准装置的研制

介绍了由临界流流量计和标准气体涡轮流量计有机组合、优势互补,分别作为传递标准和核查标准组成的气体流量标准装置的构成、工作原理、实现的主要技术指标及采取的主要技术措施。丰富了气体流量标准装置的设计思想,拓展了气体流量量值传递的途径和方法,且具有较好的社会经济效益。     

Pulsating Turbulent Flow of Gas in a Round Pipe

An analysis is performed of the presently available results of experimental and prediction studies into pulsating turbulent flow of liquid in a narrow pipe under conditions when the compressibility is apparent. It is demonstrated that the simulation of such flows in the general case may be performed only numerically, using a model of turbulence that adequately includes the effect of oscillation on turbulent transfer. Use is made of a model of turbulence whose validity is proved by comparing the calculation and experimental results for a wide range of flows. Calculations are performed for a pulsating flow of gas in pipes with isothermal and adiabatic walls, acoustically closed at the outlet, in the frequency range corresponding to the first resonance harmonic. The predicted variations of the heat flux to the wall and of the hydraulic drag, averaged over the oscillation period, as functions of the process parameters such as the Reynolds number of the mean flow and the dimensionless oscillation frequency are discussed.     

无缝钢管内折缺陷的研究

钢管内折缺陷一直是影响无缝厂400轧制作业区生产的主要原因。为了探索内折缺陷成因，从连铸坯、轧卡样、内折缺陷成品试样等进行现场试验并进行性能、低倍组织分析，总结产生钢管内折缺陷的原因。     

Behavior of Isolated Disturbances Superimposed on Laminar Flow in a Rectangular Pipe

An investigation was conducted in a horizontal transparent rectangular pipe to study the behavior, in laminar flow, of an isolated turbulent-like disturbance produced by injecting a quantity of dye into the pipe 39 feet from the entrance. As the resulting mass of colored water moved downstream, time-distance measurements were made for the front of the dye mass and for the rear of the disturbance. The experimental setup, which is described in some detail, permitted reasonable control over the mean flow rate from which Reynolds number was calculated. The utilization of the data unfolded a functional relationship among three quantities: The ratio of the velocity of the rear of the disturbance to the velocity of the front of the dye U_R/U_F; the distance from the origin, X_F; and the Reynolds number R. The similarity of this work to that being done by Lindgren in Stockholm is mentioned.