电容器用铌粉和钽粉制备技术的进展

综述了铌粉和钽粉的现行生产工艺及几种新的还原方法，介绍了金属热还原反应中的电化学反应机理。钽粉的现行生产工艺几乎都用亨特法，铌粉则大部分采用铝热还原法生产。通过对亨特法还原条件、稀释剂组成等各种工艺参数的改进，已经可以制备纯度高、形态可控的金属钽粉。铌粉新还原方法的研究主要包括金属预成形热还原法、镁等蒸气还原预成形氧化物粉末的方法、镁或钠的蒸气还原氯化物蒸气的气相还原法、以液氨为介质在低温液相中均相还原铌或钽的氯化物的方法、反应媒介熔盐在强搅拌条件下的液体镁热还原金属氧化物的方法等。     

基于扁管的蒸发式冷凝器管外传热传质特性研究

强化蒸发式冷凝器管外传热传质可有效降低系统能耗，利用Fluent软件，结合自编译程序及组分输运模型对扁管蒸发式冷凝器管外传热传质过程建模，选取了等周长圆管模型进行比较，研究了二者传热传质性能的差异。通过研究管外液膜厚度及速度，以及管外温度分布和含湿量的变化规律，对比了扁管和圆管的平均表面传热系数，结果表明扁管的平均表面传热系数于圆管提升了9.04%。模拟了风速从1.5 m·s^-1变化至3 m·s^-1以及喷淋密度从0.15 kg·m^-1·s^-1增加至0.3 kg·m^-1·s^-1时对扁管式蒸发式冷凝器换热的影响，得到随着风速及喷淋密度的增加其平均表面传热系数分别增加了5.68%和30.26%。对扁管式蒸发式冷凝器管外的传热传质特性的研究为其应用提供了理论指导。     

试析补偿电容器引起的6KV电动机低电压保护的拒动

对在供电系统短时停电的情况下由补偿电容器引起的不允许自起动的6kV电动机低电压保护拒动的原因进行了分析，提出了解决这一问题的方法和建议。     

聚光器薄膜附着力机理与制备工艺的探讨

研究太阳能聚光器薄膜在制备过程中附着力存在的有关问题。阐述薄膜在生长过程中影响薄膜附着力的各种因素，针对其相关因素作了具体的理论分析，并在真空镀膜实验的基础上，探讨了提高蒸发镀膜附着力的具体方法。     

The impact of fouling on performance evaluation of evaporative coolers and condensers

Fouling of evaporative cooler and condenser tubes is one of the most important factors affecting their thermal performance, which reduces effectiveness and heat transfer capability with time. In this paper, the experimental data on fouling reported in the literature are used to develop a fouling model for this class of heat exchangers. The model predicts the decrease in heat transfer rate with the growth of fouling. A detailed model of evaporative coolers and condensers, in conjunction with the fouling model, is used to study the effect of fouling on the thermal performance of these heat exchangers at different air inlet wet bulb temperatures. The results demonstrate that fouling of tubes reduces gains in performance resulting from decreasing values of air inlet wet bulb temperature. It is found that the maximum decrease in effectiveness due to fouling is about 55 and 78% for the evaporative coolers and condensers, respectively, investigated in this study. For the evaporative cooler, the value of process fluid outlet temperature T_p,out varies by 0.66% only at the clean condition for the ambient wet bulb temperatures considered. Copyright © 2005 John Wiley & Sons, Ltd.     

Generalized method of pressure drop and tube length calculation with boiling and condensing refrigerants within the entire zone of saturation

A simple and universal method of pressure drop and horizontal tube length calculation with boiling and condensing refrigerants within the entire saturation zone ranging from critical point down to the lowest temperatures, is proposed. The method can be applied for the calculation ofevaporators and condensers operating in conventional and non-conventional refrigeration, air conditioning and heat pump system, as well as in similar cases. By introducing a two-phase flow factor, β, and a liquid/vapour gradient ratio, θ, the correlation given by Müller-Steinhagen and Heck can be rearranged to a siple dimensionless form which leads to a family of universal curves that enable any dry-saturated vapour flow gradient to be transformed into an actual two-phase flow gradient, or vice versa, at any temperature and liquid/vapour mixture quality within the entire saturation zone of refrigerants. Determination of θ is a key factor in the accuracy of the calculation. Appropriate correlations and diagrams for predicting τ are presented in terms of corresponding states principle. Some practical advice and numerical examples of evaporators and condensers calculation are given.     

Optimization of a reactive distillation process with intermediate condensers for silane production

This work presents a reactive distillation column for the catalytic disproportionation of trichlorosilane to silane which includes three consecutive reversible reactions. This reaction system is however characterized by a large distinction in the boiling points of the components, which make the reactive distillation extremely favored. Nevertheless, the normal reactive distillation column possesses the shortage of high refrigeration requirement. By removing heat at temperature higher than that at the condenser a superstructure representation, rigorous simulations, and optimization problems were combined to derive optimal reactive distillation columns which can realize heat integration between stages and utilities at several refrigeration conditions. An iterative simulation-optimization procedure was proposed to consider temperature changes in stages due to heat integration. The results showed that the installation of two inter-condensers results in the best option with economic savings up to 56%.     

火力发电厂空冷凝汽器的腐蚀与防护

随着国内直接空冷机组的大量投入运行,空冷凝汽器的腐蚀问题日益突出。通过分析腐蚀情况和现有防腐蚀方法存在的局限性,提出了需要解决的问题和技术方向。     

国华台电凝汽器及低加水位测量改造

针对国华台电凝汽器及低加水位计经常出现的测量不准的问题进行了分析,提出一种新的差压式水位测量方案,对电厂的凝汽器及低加水位计的改造有很好的借鉴。