逆流式露点间接蒸发冷却器性能实验研究

本文研发了一种新型逆流式露点间接蒸发冷却器,并对其冷却性能进行实验研究。在焓差实验室内模拟干燥地区、中等湿度地区、高湿地区等多种工况条件,对该冷却器的湿球效率、露点效率、制冷量等进行测试分析。结果表明:在标准干燥工况(干球温度38℃,湿球温度23℃),二次空气/一次空气风量比=1.1条件下,该冷却器湿球效率可达105.6%,露点效率可达76%,制冷量为2.83 kW,干球温度温降可达15.2℃。模拟乌鲁木齐工况与标准干燥环境工况的实验结果表明,露点间接蒸发冷却技术在我国西北炎热干燥地区具有极大的优越性和广阔的应用前景。     

数据中心用露点间接蒸发冷却与机械制冷复合空调的实验研究

为了降低数据中心空调能耗并提高换热效率,本文提出一种应用于数据中心的流道结构为逆流和叉流结合的露点间接蒸发冷却与机械制冷复合空调,并搭建了实验台分别对干燥工况和高湿工况下回风温度为26 ℃和35℃的不同运行模式进行实验测试。实验结果表明:运行湿模式,当数据中心回风温度较低为26 ℃时,干燥工况下机组的湿球效率最高为97％;当数据中心,回风温度较高为35 ℃时,干燥工况下机组的湿球效率约为110％,高湿工况下机组湿球效率为99％;运行混合模式,干燥工况下露点间接蒸发冷却器的湿球效率约为120％,高湿工况下露点间接蒸发冷却器的湿球效率约为110％。由测试结果可知,露点间接蒸发冷却技术在干燥地区更加适用,中等湿度和高湿地区需辅助机械制冷,尤其当回风温度较低时,高湿工况蒸发冷却应用受限,必须辅助机械制冷达到送风要求,回风温度较高时,蒸发冷却可以减少机械制冷的使用时间。     

数据中心空气侧蒸发冷却技术性能及适用性分析

总结了空气侧蒸发冷却技术在数据中心的研究现状,对直接、间接及露点间接蒸发冷却技术的工作原理进行理论分析并对三者在高湿工况下的性能进行测试,结果表明,所测蒸发式冷气机最佳风速在1.8m/s;间接蒸发冷却空调机组最佳二/一次风量比为1.5;露点间接蒸发冷却空调机组最佳二/一次风量比为1.7,并且此时效率可达到96.5％,有...     

露点蒸发冷却装置性能评价指标的研究

本文通过搭建逆流式露点蒸发冷却装置,实验研究了空气入口温度、湿度和风速对露点效率、湿球效率、火用效比等各性能评价指标的影响,提出了能够反映湿通道潜热交换的强弱和装置性能的适用于露点蒸发冷却的评价指标——换热放大系数。研究结果表明:进口温度为33℃、相对湿度为22%时,当风速从1 m/s增至3 m/s,制冷量从29.5 kW增至69.0 kW,换热放大系数呈先增后减的趋势,在风速为1.8 m/s时达到最大值;当入口空气的温、湿度不同,湿球、露点效率的变化规律与温降趋势及制冷效果不一致,不宜作为装置性能的评价指标;当相对湿度为43%、风速为1.3 m/s,进口温度由25℃升至40℃时,换热放大系数由11增至54,变化规律与降温效果一致,能够反映装置冷却性能。在高温低湿工况下,火用效比大、装置节能性能好。     

有冷凝和没有冷凝的板式间接蒸发冷却器性能分析比较

在不同的参数条件下，对一次空气通道有冷凝和没有冷凝的板式间接蒸发冷却过程进行了三维数值模拟。根据间接蒸发冷却过程的热力学特性，定义了间接蒸发冷却器的[火用]效率计算公式。通过对不同的入口速度、浓度以及通道宽度条件下的模拟和计算结果进行分析比较，得到了影响换热效率的因素，并从热力学第二定律的角度对换热器进行了[火用]分析。     

交叉式露点间接蒸发冷却空调机组性能测试研究

为了研究高湿度地区夏季交叉式露点间接蒸发冷却空调机组的性能,2013年7月1-12日在福建省福州市某公司对该空调机组进行了研究,通过测试和计算分析的得出：二一次最佳风量比为1.08,对应湿球效率为91％;最佳风量比下最佳淋水密度625kg/（m·h）;间歇供水时间是制冷15s、通风约为5～6min;最佳风量比和最佳淋水密度下的耗水指标为10.8L/h;制冷量为7.6kW、能效比为15.3.结果表明：交叉式露点间接蒸发冷却空调机组湿球效率接近100％,达到单独使用直接蒸发冷却的效果,而且还不增加空气的合湿量,同时,该机组不仅适合在高湿度地区,在中等湿度地区和干燥地区应用其制冷效果将会更好.     

基于露点板式间接蒸发冷却器空调机组特性的探讨

通过对目前国内外露点间接蒸发冷却技术的发展进行介绍,提出一种基于露点板式间接蒸发冷却器的空调机组—露点间接—直接蒸发冷却空调机组。并对此空调机组的原理和特性进行了分析,结果表明这种空调机组与传统露点间接蒸发冷却器相比,温降幅度大,可以进一步逼近室外空气的露点温度,是露点间接蒸发冷却技术的一个新发展。同时还对这一机组的性能测试提出了一些研究方法。     

间接蒸发冷却板式换热器换热性能的数值模拟

应用计算流体力学(CFD)方法建立了间接蒸发冷却板型换热器内三维层流流动与传热的数学物理模型;对影响蒸发冷却换热器换热性能的主要因素进行了数值计算和预测;通过计算表明,换热器通道间距、空气的迎面风速,以及一次风的干球温度的变化对换热器效率有很大的影响;分析了不同参数时通道内流场、能量场以及换热器效率的变化.     

循环水冷却用蒸发冷却冷水机组性能测试

针对目前工业领域存在的循环水冷却问题,设计采用蒸发冷却冷水机组实现循环水的冷却。该机组由立管间接蒸发冷却器、直接蒸发冷却填料、闭式换热盘管组成。对机组进行风量测试及热水试验,结果表明:机组在高湿度地区运行时,立管间接蒸发冷却器的最佳风量比(二次/一次)为0.79,机组的冷却效率高达65.2%;机组对50℃左右的循环水进行冷却,温降幅度为20℃,降温效果较好。最后针对测试中存在的主要问题提出改进措施。     

露点间接+直接蒸发冷却空调机组节能性分析

介绍露点间接+直接蒸发冷却空调机组节能工况点和一二次风量比以及效率的选择确定,计算机组在不同气候地区能耗和制冷量以及能效比,分析机组的节能性,指出合理的风机风量和风压、水泵流量和扬程以及淋水密度是露点间接+直接蒸发冷却空调机组节能设计的关键环节。为露点间接+直接蒸发冷却空调机组的设计和推广应用提供参考。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.