某型运输机飞行状态下冷凝器风道性能

以某型运输机蒸发循环制冷系统用冷凝器为研究对象，分析了运输机与直升机、小型通航飞机蒸发循环制冷系统工作环境的区别，应用Star CCM+软件进行了仿真建模，通过对冷凝器风道的流体仿真分析，阐述了飞行状态下引起蒸发循环制冷系统压力故障的原因，在此基础上提出了冷凝器风道优化方案，并应用流体仿真分析的方法，验证了优化方案的有效性，最后在该运输机上进行了试飞验证。     

Rapid degradation characteristics of an air-cooled PEMFC stack

Durability is one of the obstacles to the large-scale commercialization of proton exchange membrane fuel cell (PEMFC) stacks. Understanding its decay behavior is a prerequisite for improving durability. In this study, rapid degradation characteristics of an air-cooled PEMFC stack are investigated. Due to the simultaneous presence of various degradation sources, the maximum power of the PEMFC stack has been reduced by 39.6% after just 74.6 h of operations. Performance degradation characteristics are sought by analyzing the cell voltage, temperature distribution, ion chromatography, and surface morphology of the gas diffusion layer. The result shows that abnormal cell voltage and temperature distribution can reflect the problematic location. The fluoride ion emission rate is 0.111 mg/day, which proves that the membrane has been seriously degraded. Contact angle reduction and impurities attached to the surface of the gas diffusion layer lead to the water management failure. It is also found that the main factor for performance degradation could be different under different current conditions. And more information can be found under higher current conditions during monitoring the decay of PEMFCs. This study helps to deepen the understanding of performance degradation characteristics.     

基于背压和最佳阀位控制的滑压曲线实时优化及应用

针对目前凝汽器背压对滑压值的修正无普适算式可供遵循的问题，通过作图法推理获得了滑压设定值与凝汽器背压及机组负荷之间的二元函数表达式；利用流量变工况计算方法解决最佳综合阀位的确定问题，在满足机组日常运行需求的条件下达到汽轮机高压调阀节流损失最小化；将提出的基于凝汽器背压和机组负荷的二元函数滑压实时优化和基于流量变工况计算的最佳综合阀位控制滑压实时优化方法相结合，将凝汽器背压对滑压值的修正作为粗调，将最佳综合阀位控制对滑压值的修正作为细调，共同实现对滑压设定值的实时调整。在某660 MW超临界机组上的应用表明，该方法能够节约供电煤耗约1.12 g/(kW·h）。     

商用空调室外机冷凝器的布局和设计分析

冷凝器是空调室外机中的重要零部件,根据其结构形式的不同可分为多种不同的类型。商用空调中常用类型为翅片管式冷凝器,它在不同类型的空调室外机中有不同的布局和结构。本文重点分析商用顶出风空调室外机中冷凝器的布局和设计。     

125MW机组循环冷却水系统改造

云浮电厂125 MW发电机组的闭式循环冷却水系统主要由冷却水塔、循环水泵和凝汽器等设备组成。经过多年生产运行,机组真空偏低。针对问题原因进行分析,介绍了通过对循环冷却水系统的改造来解决这一问题。     

制冷剂流路对冷凝器换热特性的影响

对于复杂流路的肋片管换热器进行了换热性能实验，实验用冷凝器流路分别为1～4路，在实验条件下，2路的设计达到了最大的换热量。根据试验结果分析了产生换热性能差异的原因。     

全年供冷的风冷式冷水机组问题分析与解决

风冷式冷水机组在环境温度较低时，可能出现冷量急剧减少等问题。本文对于产生问题的原因进行了分析，提出采用热力膨胀阀并联毛细管和控制冷凝风机开机数量的方法，来维持机组在大的环境温度变化范围内正常工作，给出了具体的控制策略。应用本文方法所设计的冷水机组，已在实际中得到应用，实现了全年正常供冷。     

空气冷凝汽器支架结构体系动力特性测试

对四个不同电厂的空气冷凝汽器支架结构体系进行了现场动力特性测试,通过功率谱和传递函数分析,获得不同结构形式的空气冷凝汽器支架结构的实际动力特性参数,并对实测结构进行有限元模态分析,对比实测结果和理论分析结果,该类结构以空间扭转振动为基本振型。由于结构沿竖向质量和刚度分布不均,造成了钢筋混凝土管柱和钢桁架平台底面连接处以及钢桁架平台顶面与A型架连接处成为结构的薄弱部位,设计时应予以加强。     

使用R407C冷媒的翅片管冷凝器的计算机模拟

本文针对R22的替代工质R407C，采用稳态分布参数法，对翅片管冷凝器进行了计算机模拟：对制冷剂整个流动方向的温度、饱和温度、干度、换热量、压力、管内换热系数进行了模拟计算并加以分析，并以回路为基本单位，比较了回路之间换热情况的差别，为系统的仿真以及使用R407C的翅片管冷凝器的设计打下基础。     

Disinfection of circulating water systems by ultraviolet light and halogenation

Continuous ultraviolet light (u.v.) and chemical disinfection of circulating water systems were evaluated. Direct comparisons of the biocidal effectiveness of u.v. light vs halogenation were tested with Legionella spp and Pseudomonas aeruginosa because of their association with the acquisition of overt clinical disease from water-containing appliances. Findings indicated that six species of Legionella and P. aeruginosa were killed by a moderate level of u.v. radiation. L. pneumophila and other bacteria in a circulating water system were effectively killed by a biocidal u.v. light. However, free chlorine levels needed to kill Legionella, Pseudomonas, and Flavobacterium within 1 min were found to be greater than 4 mg ml^?1. Data from a long-term field trial with u.v. light treatment of evaporative condenser water showed a significant reduction in numbers of bacteria. Ultraviolet disinfection of hospital hydrotherapy whirlpools confirmed the utility of this mode of disinfection under circumstances where chlorination may not be practical for medical reasons. These findings were confirmed during investigations of halogenated or u.v.-treated public hot tub/whirlpools. The effectiveness of routine chemical disinfection for controlling microbial flora in a cooling tower was also evaluated. The 2 month survey indicated that the numbers of bacteria, including Legionella, were not affected by two biocides that were used. The observations made during this investigation support the conclusion that u.v. light disinfection of water-containing systems may be an appropriate alternative or supplement to chemical biocides.