不锈钢在烟气脱硫系统中的腐蚀行为

火电厂烟气脱硫系统的设备腐蚀问题比较严重,选材较为关键.为此,选用304不锈钢和2205双相不锈钢,考察了其在烟气脱硫模拟介质(死亡绿液)中不同温度和不同浸泡时间的腐蚀行为.结果表明:304不锈钢在死亡绿液中随温度变化腐蚀性很敏感,易发生点蚀,不宜用作烟气脱硫装置及其零部件;2205双相不锈钢在烟气脱硫模拟介质中不同温度和时间范围内都有良好的耐蚀性,可用作烟气脱硫装置及其零部件的材料.     

小型太阳能气泡泵吸收式制冷机研究

本文确定了设计计算参数下小型太阳能气泡泵吸收式制冷机制冷循环中各状态点参数,进行了发生器、冷凝器、蒸发器、吸收器、溶液热交换器的热负荷计算和加热热水、冷水、冷却水、稀溶液等循环介质的流量计算.进行了发生器、冷凝器、蒸发器、吸收器、溶液热交换器等换热设备所需的传热面积计算.根据求得的传热面积确定了各换热设备的传热管数,计算了热水进出口配管、冷却水进口配管、冷媒水进口配管的内径尺寸,为开发小型吸收式制冷机提供了一定的理论和实践基础.     

低温过程的功储法热力学分析

一、基本概念包括深度冷冻在内,任何一个低温循环都是由一系列连续的过程所组成,工作介质在通过它们之后具有较少的内能。在低温状态下的工作介质不仅具有较少的内能,而且具有较低的熵。在一般情况下,低温设备包括压缩机、膨胀机、节流阀和热交换器等部分。在热力学第一定律的基础上,对任何一低温设备都可以写出下列热平衡和物料平衡方程式:     

利用低温排热水热量的双效吸收式制冷机

利用天然气体发动机排气的热量 ,可将水加热至 80～ 93℃。在双效吸收式制冷机中 ,可将这种温度的热水通过一台附加的热交换器加热从低温热交换器出来的稀溶液。由于提高了进入高温热交换器的溶液温度 ,从而减少了高压发生器的燃料消耗。模拟计算和实际试验都证明由于利用了排热水热量 ,在全负荷下燃料消耗可减少 12 % ,而在 60 %负荷下燃料消耗可减少 2 2 %。随着负荷的减少 ,利用排热水热量的效果也愈大     

煤矿锅炉房热交换器比较及选型

本文阐述了现用浮动盘管式热交换器、板式热交换器的使用情况及通过对板式热交换器、浮动盘管式热交换器和螺旋螺纹管热交换器从设备的结构、体积、传热效率、节能等几方面阐述了三者的特点,进行比较分析,为锅炉房热交换器的选型提供了参考依据。     

制氧工问题浅解(二二)

1．问:怎样判断小型制氧机热交换器冻结?答:小型制氧设备热交换器冻结的明显征象是热端温差增大,热交换器前后压差不断增加,高压空气节流阀前的温度升高。这是因为热交换器内的小管被油脂,水份和二氧化碳所堵,使小管内径缩小,换热性能降低而引起的。     

汽车空调暖风机热交换器的优化设计

提高汽车空调性能的主要方式是提高热交换器的换热效率. 由于汽车内部空间的限制,不能单纯依靠增加热交换器体积的方法来提高热效率,因此对热交换器结构优化设计将具有现实意义. 利用Flnent求解和正交设计的方法对汽车暖风机热交换器进行优化设计. Fluent软件可以模拟热交换器的流动和传热过程,正交设计的方法可以建立回归方程,因此可以得到出口温度的数学模型,该模型定量地描述了翅片间距、翅片高度及水管间距对换热效率的影响,优化汽车暖风热交换器的结构,最后通过试验证明了优化设计结果的准确性.优化热交换器的结构参数：翅片间距为1.1 mm,翅片高度为6.9 mm,管距为5.2 mm.根据Fluent模拟仿真得到出口温度的回归方程：Y=307.308+2.333X₁ +0.677X₂+0,561X₃-2.501X₁²,影响出口温度的因素依次为翅片间距、翅片高度和水管间距.Fluent模拟仿真和正交试验设计相结合的方法有助于产品结构分析和优化设计.     

热交换器冷却板局部穿孔失效分析

通过金相分析及断口观察,对热交换器冷却板局部穿孔失效进行了系统分析.结果表明,机组运行中受介质不断冲刷而产生的不均匀腐蚀疲劳剥落是失效的根本原因.     

基于标准表法的高压环道标准装置设计

天信仪表集团有限公司和德国EEE公司联合设计开发了一套以空气为介质以标准表为传递标准的高压环道标准装置。该装置2014年底取得欧洲VSL证书并开始运行,可以检测20 bar以下气体流量计在不同压力状态下的计量特性,为气体流量计的高压实验提供了依据,也为我们国家高压标准装置的设计提供了参考,是国内第一套由企业自己设计的高压空气环道标准装置。装置主要包括标准表组件、高压风机、热交换器、冷却系统、计算机控制系统、压缩机组件、被检表组件7个部分。冷却系统和热交换器是意大利生产的原装设备,稳定性好,一次检测的温度变化不超过0.1℃。标准表采用并联方式,检测流量为1~2 500 m3/h(工况),检测压力为1~20 bar,检测温度为15~25℃,达到预期性能指标。     

溴化锂吸收式制冷系统溶液热交换器的传热性能研究

以板式溶液热交换器为例，建立物理数学模型。通过对模型的求解，得到溶液热交换器在不同流速下的传热特性。计算结果表明，提高溶液热交换器中的溶液流速可以提高其传热系数，但会导致溶液的进出口温差减小，使溶液间换热不充分。设计溶液热交换器时可根据设计要求与文中计算结果选择不同的溶液流速。     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。     

Surface-charge density and potential of coal-liquid mixtures and control of their stability and fluidity

The preparation conditions of concentrated (>70%) aqueous suspensions of coal were optimized, as were the surface charge density and the surface potential of the coal-water suspensions. The theoretical study showed that (1–3) or (2–3) electrolytes such as Na₂SO₄ or Na₅P₃O₁₀, greatly increase the surface charge density and the surface potential of the coal particles in water. This study has led to the interesting result that thinners and stabilizing agents of concentrated clay suspensions, such as lignosulphonates, tripolyphosphates, polynaphtalene sulphonates, etc., must also be good thinners and stabilizing agents for ground coal-water suspensions. Two parameters were controlled: the stability and the fluidity of the suspensions. A penetrometry technique revealed the importance of the resistance coefficient,C _r that can be used as a criterion for the evaluation of coal-water mixture stability and fluidity. Concentrated coal suspensions (about 75% of solid by weight) were prepared in water by using different additives, for instance sodium tripolyphosphate (NaTPP) and surfactants like lignosulphonates (by coupling of the dispersion and stabilizing effects) with the optimum concentration ratio of these two products equal to 1.9. The stability of the suspensions was then greater than 2 months and the viscosity was 1900 cP.     

SARS传染病数学建模及预测预防控制机理研究

首先，利用疾病传播的一般规律及人口守恒统计法则建立了四类人的SARS传染病数学模型，然后运用数学方法对四类人的SARS传染病数学模型进行分析，得出了其生理意义和预防、控制机理。其次，利用人工神经网络理论建立了SARS的预测模型，以北京市的SARS数据为例进行了预测和分析，预测结果显示该模型简单易行，预测精度高。     

SiH4,Si2H6的制备与分离

用Mg2Si制备SiH4必然伴随产生Si2H6.经二级低温冷凝 ,分子筛吸附和恒温恒压汽化等工艺技术过程,能够对两种气体进行最有效的分离 .并且可以制备Si2H6和总杂质含量≤10×10-6,基磷＜0.2×10-9, 基硼＜0.05×10-9的高纯SiH4.