Study on Microstructure and Mechanical Properties of Hot Rolled Low Silicon Containing Phosphorus TRIP Steel

The effects of final air cooling temperature on the microstructure and mechanical properties of hot rolled 0.2C-1.9Mn-0.5Si-0.08P TRIP steel were studied by utilizing OM, SEM, TEM and tensile tests. Experimental results showed that in the multiphase microstructure of the investigated steel when the finish rolling temperature was about 820 ℃ and the final air cooling temperature was in the range of 630-700 ℃, the grain size of most of ferrite was finer (about 4 μm) and which had higher dislocation density, t...     

Internal surface protection of gas turbine blade by Si‐aluminide coating

A laboratory‐scale slurry silicoaluminizing process has been developed to apply coating into cooling passageways of a first‐stage gas turbine blade. Analytical techniques for characterizing the coatings comprised optical microscopy, SEM, EDS, and XRD. The results of metallographic examinations demonstrated that acceptable coatings had been formed in almost all of the passageways. The amounts of Al and Si in the topcoat were found to be in the ranges of 24–26 wt% and 4.5–6 wt%, respectively. The heat treated coating consisted largely of β‐NiAl phase as the coating matrix with uniform distribution of <2 µm‐size precipitates. In addition, oxidation and hot corrosion performance of the coatings were investigated by cyclic exposure to 1100 °C and the furnace method using a mixture of sodium sulfate‐40 wt% sodium vanadate‐10 wt% sodium chloride at 780 °C, respectively. It was found that the presence of Si in the coating improves both oxidation and hot corrosion Type II properties.     

Analysis of the energy performance of a ground source heat pump system after five years of operation

GeoCool plant was the result of a EU project whose main purpose was to adapt ground coupled heat pump technology to cooling dominated areas. The execution of this experimental plant was completed at the end of year 2004, starting on February 2005 the regular operation of the air conditioning system. Since then, GeoCool facility has been monitored by a network of sensors characterizing its most relevant parameters. Several aspects of the performance and behaviour of the system during its first operational year were presented on a previous paper. This paper presents the energy performance measurements of GeoCool ground coupled heat pump system acquired during five years of operation as well as the evolution of the return water temperature from the ground as a representative of the ground temperature. The analysis of the experimental results shows that the system energy performance is maintained through the years with no appreciable impact on ground thermal response.     

蒸发冷却技术在大功率模块冷却中的应用

以特殊场合电力电子变流装置中器件的冷却为出发点,详细论述了蒸发冷却技术在一套800kVA变流装置中的应用,给出了其运行原理、实现方法和试验数据。现场调试运行结果表明,该套装置具有体积小、安全可靠、冷却效率高等特点。同时,由于去掉了风机,降低了噪声,而且基于蒸发冷却本身的特点,使得该套装置中的器件(IGBT)壁面温度不受外界环境的影响,保持在45℃左右(可通过改变腔体内部的压力来调节)。整个装置运行取得了较好的冷却效果,满足了特殊场合的需要,从而为大功率器件的冷却提供了一种有效的实现方法,具有较好的应用和推广价值。     

大型空冷汽轮发电机冷却技术的现状与分析

本文分析了空冷技术当前受到重视的原因.通过对国内外空冷汽轮发电机发展状况的分析,指出了国内进一步研究空冷技术的必要性.通过对空冷汽轮发电机冷却原理的介绍,对空冷技术改进的可行性进行了分析.     

LSF-Z型密闭式纯水冷却系统的研制与应用

LSF-Z型密闭式纯水冷却系统主要由电气控制回路、主循环冷却水回路和副循环去离子回路构成。分析了其工作原理及水风换热器、主循环水泵和主过滤器等主要零部件的功能,介绍了该系统出厂前的试验项目及试验内容。通过实际工程应用表明,该系统能够满足高压大功率电力电子装置的冷却要求,保证了电力系统安全稳定地运行。     

DRF-J45型镓单晶炉的开发与设计

当前镓提纯方法大部分采用电解法,电解法生产出的镓晶体纯度不高,常常形成个别杂质元素超标。为了提高其晶体纯度,需采用晶体提拉法来进一步弥补并提升镓晶体提纯工艺方法。从分析镓单晶炉生长的工艺特点出发,简要介绍镓单晶生长设备的设计思想以及新近开发设计的新型镓单晶炉的机械结构及电气控制系统。     

高功率密度数据机房无连续制冷的风险分析

随着高功率密度数据中心的发展,空调系统的持续制冷能力已成为决定高功率密度数据中心能否安全、稳定运行的重要因素之一。本文通过实验对高功率密度数据机房无连续制冷的风险进行了分析,并结合实验结果对高功率密度数据中心的建设提出了一些建议。     

被动冷却系统于混凝土屋顶应用研究进展

在炎热气候条件下,由混凝土结构构成的建筑物往往会有不让人满意的热力学性质,比如说较高的内部温度,特别是没有那些主动的冷却系统。相比于混凝土层屋顶,添加被动冷却系统的屋顶显示了它慢热的时间响应,当热量传递减少时,这是一个理想的性质可以用来控制热的波动。探究多种被动式冷却系统于混凝土建筑的屋顶的应用。     

数据中心集中冷源空调系统设计综述

介绍了数据中心空调系统中集中冷源式空调系统的节能设计要点,包括冷水机组、水泵、冷却塔、蓄冷装置、水系统管路的分类及选型。并根据不同气候条件提出了不同的制冷系统架构的建议。