密度站偿饱和蒸汽流量测量系统

本文提出一种具有流体密度变化补偿的饱和蒸汽微机流量测量系统。     

饱和蒸汽压的测试线路

1984年为兰州西固石油站制作了一台经过改进的油脂饱和蒸汽压测定仪.主要在测量控制线路和温度控制方面作了较大改进.研制出了用晶体管线路代替电子管线路的测量线路.不仅仅在实验精度上,而且在体积和功耗上都优于1963年研制成功的真空油脂饱和蒸汽压测定仪.在第一部分,介绍了这台仪器的测量原理.没有采用悬摆法,而是采用蒸发速度法来测量油脂的饱和蒸汽压.蒸发速度法是先测出一组较高温度下的饱和油蒸汽的蒸发速度,然后推算任意温度下油的饱和蒸汽压的一种实验万法.第二部分介绍了测试装置.着重介绍了测量控制线路以及对邻苯二甲酸二丁脂的测试结果.并与1984年研制成功的微机测控油蒸汽压的实验结果作了比较.最后对实验结果进行了讨论和分析.     

弯管流量计在饱和蒸汽测量中干度的影响

弯管流量计测量饱和蒸汽流量时,饱和蒸汽的干度变化对测量准确度影响很大,如采用固定干度补偿,测量结果与真实值比会有较大误差。文章依据现场实例,结合弯管流量计测量过程,进行了详细的分析和说明。     

密度补偿饱和蒸汽流量测量系统

本文提出一种具有流体密度变化补偿的饱和蒸汽微机流量测量系统。论述了微机流量测量数据处理公式，给出了系统硬件、软件程序框图。该系统测量流量精度可达1％。有效地补偿了由于流体压力变化引起密度变化的影响。     

用涡街流量计测量饱和蒸汽时存在的问题和解决方法

用涡街流量计测量饱和蒸汽时存在的问题和解决方法徐文尚（山东矿业学院济南分院，济南２５０８３１）涡街流量计在测量饱和蒸汽质量流量时，因压力波动、干度变化、振动、压差过大等因素影响着正确测量。本文根据实践给出了解决上述问题的方法。一、存在的问题工业现场常...     

用涡街流量计测量蒸汽时的误差分析

本文介绍用涡街流量计测量蒸汽时的误差分析,包括蒸汽计量的系统介绍,蒸汽计量的系统管路安装情况及蒸汽计量的误差分析等.     

称重式蒸汽干度测量装置的设计

在工业生产和生活中,蒸汽干度是不可忽视的重要物理参数.现有的蒸汽干度测量方法有探针法、电容法、热线法、节流法、凝结法、蒸汽空气混合法和加热法等,采用这些方法的测量仪器或装置不是价格昂贵,就是装置复杂且测量精度低.在现有基础上对蒸汽干度测量方法进行了研究,设计了一种称重式蒸汽干度测量装置,介绍了测量装置的测量原理、组成和工作原理、使用方法及性能.     

如何提高饱和蒸汽计量系统测量精度

饱和蒸汽是重要的二次能源，蒸汽流量的计量是流量计量的难点。本文阐述了蒸汽流量计量的特点，讲解了测量分析，并提出了提高蒸汽流量计量精度的方法。     

蒸汽计量存在的问题及解决办法

蒸汽流量测量难度较大,因为蒸汽是比较特殊的介质,随着工况（如温度、压力）的变化,单相性质的过热蒸汽经常会转变成为饱和蒸汽,形成汽液两相流介质。目前,能准确测量汽液两相流介质的流量计量仪表几乎没有,解决两相流计量问题的办法是加强蒸汽管道的保温措施.     

过热蒸汽变为饱和状态时的流量计量误差分析

蒸汽流量测量是节能及过程控制的重要检测环节.随着蒸汽价格的大幅度上涨,准确地计量蒸汽流量对于企业加强经济核算、节约能源、降低成本具有重要的意义.由于蒸汽输送管线长短不一,用量不均衡,过热蒸汽往往在到达用户端时热力参数变化较大,甚至已变为饱和蒸汽,使原设计流量计量装置产生较大的计量误差.本文通过理论分析和实验,对这种情况下产生的误差进行了确认,并提出了修正方法.     

竖直矩形通道内不凝性气体对凝结换热特性的影响

本文以去离子水为工质,实验研究了竖直矩形窄通道内少量残余不凝性气体对蒸汽凝结换热特性的影响。采用热阻分离法得到凝结侧换热表面传热系数,分析了不凝性气体的含量、冷却水质量流速、进口温度和热流密度对蒸汽凝结侧表面传热系数的影响。结果表明:当热流密度为1.668 kW/m~2,即蒸汽质量流速较小时,2%体积分数的不凝性气体使凝结侧表面传热系数下降了33%,但当热流密度为3.887 kW/m~2,蒸汽质量流速较大时,2%体积分数的不凝性气体仅使凝结侧表面传热系数降低了14%,此外,凝结换热表面传热系数随冷水质量流速和不凝性气体分数的增加而变小,随冷水进口温度和热流密度的增加而变大。     

Relaxation properties of non-equilibrium wet steam flows

Internal relaxation processes in wet steam flows through channels and nozzles are analysed basing on derived general equations describing non-equilibrium wet steam processes. Characteristic relaxation distances for single-deviation processes are determined and their application is discussed. As a synthetic intensity measure of complex multi-parameter processes a concept of entropy relaxation distance is introduced. Calculation methods of wet steam relaxation processes and thermodynamic loss determination are presented.     

Systematic Errors in Measuring the Energy of Wet Steam with Dry-Steam Meters

Systematic errors are considered in measuring mass flow rate, specific enthalpy, thermal power, and energy for wet steam by means of meters intended for dry saturated steam.     

软木纤维蒸汽闪爆改性及其形态结构表征

研究采用高压热蒸汽闪爆技术，对软木纤维进行物理改性，通过对闪爆前后纤维素表征分析，结果发现，高压闪爆再生的纤维素形态，聚合度，在稀碱中的溶解度有极大改变，因原纤形态的差异，几种纤维素的闪爆改性的难易程度为，麻，棉，硬木，软木，经过一定压力及温度闪爆可得到在NaOH碱溶液中完全溶解的软木纤维，这一结果可使粘胶工业实现稀碱溶液直接湿纺的技术。     

空分设备配套汽轮机叶轮结垢原因及处理

由于蒸汽中二氧化硅含量超标,造成空分设备配套汽轮机叶轮和流通部件结垢,导致汽轮机负荷下降,影响空分设备的正常运行。采用低压饱和湿蒸汽蒸煮的方法清除垢物,使汽轮机的负荷恢复正常。介绍汽轮机叶轮和通流部件结垢时的参数变化情况和结垢原因的分析过程,阐述蒸煮方法的实施步骤和预防措施。     

Numerical analysis of spontaneously condensing phenomena in nozzle of steam-jet vacuum pump

The primary fluid in a steam-jet vacuum pump is not assumed as a perfect gas as general research in the present study. A mathematic model based on the wet steam model for transonic flow is proposed to investigate the flow behaviours of primary fluid in the nozzle of a steam-jet vacuum pump. The simulation based on a wet steam model was carried out to predict the flow characteristics of primary fluid along the nozzle axis by a commercial computational fluid dynamics (CFD) code (FLUENT6.3). The simulation results showed that there was spontaneous condensation as the supersonic flow passing through the nozzle and the simulation results had a good agreement with the experimental data. It is found from the numerical simulation results that the steam flow characteristics in nozzle are quite different from a wet steam model and a perfect gas assumption: the outlet pressure of the nozzle predicted in the present study is higher than that as the primary fluid assumed as perfect gas, the outlet velocity is about 10% lower than that as the primary fluid assumed as a perfect gas, and the temperature at the outlet of the nozzle is much higher than that as the primary fluid assumed as a perfect gas. The simulation results demonstrate that the thermo-positive process due to steam condensation would hinder the supersonic expanding flow process in nozzle and depress the efficiency of the nozzle which would affect the pumping performance of steam-jet pump.     

Properties of lime stabilised steam-cured blocks for masonry

The paper addresses certain issues pertaining to the technology of lime-stabilised steam-cured blocks used for masonry construction. Properties of lime-stabilised steam-cured blocks using expansive soils and tank bed soils have been examined. Influence of parameters like steam curing period, lime content and fly ash content on wet strength of blocks is studied. Steam curing of lime stabilised blocks at 80°C for about 20 hours at atmospheric pressure leads to considerably higher strengths when compared with curing under wet cloth at ambient temperatures. Clay-fly ash fractions of the mix control the optimum lime content yielding maximum strength. Long-term strength behaviour of steam-cured blocks has been monitored. The results indicate a favourable lime-clay ratio for stable long-term strength. A small-scale steam cured block production system has been designed and implemented to construct a load bearing masonry structure, thus demonstrating the potential of steam-cured block as a material for masonry construction.     

Mit Wärme Kälte erzeugen

A steam jet cooling plant Steam jet cooling plants with water as a medium to be cooled are preferably used to chill down to 0°C and below. Since most industrial enterprises have steam and cooling water supply nets already, steam jet cooling plants can be installed there quite easily. They are characterised by ‐ low investment costs, ‐ robust and simple construction, ‐ immediate response to changes of the required cooling capacity, ‐ very low maintenance and spare parts costs. Under certain conditions even hot water or waste steam (low‐pressure, vacuum or wet steam) can be used as a motive medium. A surplus of steam, perhaps, which occurs during the summer may be used for cooling purposes, easily. Below a steam jet cooling plant for a district cooling system is described which has been installed with the company Energieversorgung Gera GmbH (Gera, Germany). Since then, it has been worked successfully. The maximum chilling capacity is 600 kW (12°C/6°C).     

基于金属磁记忆的热采湿蒸汽发生器炉管缺陷早期检测

对湿蒸汽发生器20G炉管进行了拉伸静载荷实验、疲劳实验及磁记忆信号采集,通过对采集到的磁记忆信号进行分析,得到了20G炉管在不同加载阶段和不同疲劳周期的磁记忆信号变化规律以及金属磁记忆技术定量评估早期缺陷的方法,并应用于油田现场炉管检测.结果表明:金属磁记忆法可以准确表征被测工件的应力集中区;当20G炉管磁场梯度值K大...     

Liquid film and droplet stability consideration as applied to wet steam flow

The state of art and ongoing research concerning the flow of wet steam in large steam turbines is reviewed, particularly from the viewpoint of the behavior of the liquid film deposited upon the stationary blading. New experimental results concerning the non-steady behavior of the film and the resultant wavelet formation patterns under the action of high-velocity low-pressure steam flow are presented. These results are then correlated as a flow regime “map” showing various flow regions in terms of steam velocity (or relative steam-film velocity since film velocity is relatively very small) vs. film flow rate per unit transverse distance. The distribution of liquid droplets shed from the blade trailing edge in the wake are studied as a function of distance downstream, steam velocity, and liquid film flow rate. In addition the droplet size is correlated in terms of critical droplet Weber number and compared with results of previous investigators. High-speed photographs of droplet distortions in a high-velocity air stream are also included.