深冷文献消息(国内部分)

20 0 35 10 1　低温氦气体轴承透平膨胀机的设计侯　予等　《低温工程》　 2 0 0 3　№ 3　 7～ 11,162 0 0 35 10 2　涡流管热力学方法的研究曹　勇等　《低温工程》　 2 0 0 3　№ 3　 12～ 162 0 0 35 10 3　脉管制冷机工作过程数值模拟的Lax Wendroff算法研究张　力　《低温工程》　 2 0 0 3　№ 3　 17～ 2 32 0 0 35 10 4　氦氢混合制冷工质的爆炸极限试验孙爱国等　《低温工程》　 2 0 0 3　№ 3　 31～ 33,5 9对不同配比的氦氢混合气进行爆炸试验 ,分别得到了它们的爆炸极限。结果表明 :氦气对氢气虽然具有一定的阻燃作用 ,但当样…     

采用二元混合工质的脉管制冷机实验研究

首次在８０Ｋ温区脉管制冷机中采用混合工质进行了实验研究,实验结果表明,在其它运行参数不变的情况下,在氦氢二元混合工质中,当氢的摩尔浓度为２０％时,可获得比纯质氦高的制冷量。     

二元混合工质脉管制冷特性研究

从制冷工质角度，在理论上分析了采用混合工质代替纯质氦以提高脉管制冷机在８０Ｋ温区制冷性能的可能性。初步的分析得到了两组二元混合工质对，一组在８０Ｋ温区附近依旧保持气态，如氦－氖，氦，－氢，氢－氖，另一组在８０Ｋ温区附近处于气液两相，如氦－氮，氢－氮，氖－氮，其中，氮气的摩尔组分小于１０Ｔ。     

气体工业名词术语

高纯气体（ＨｉｇｈＰｕｒｉｔｙＧａｓｅｓ）通常指利用现代提纯技术能达到的某个等级纯度的气体。对于不同类别的气体，纯度指标不同，例如对于氮、氢、氩、氦而言，通常指纯度等于或高于９９．９９９％的为高纯气体；而对于氧气，纯度为９９．９９％即可称高纯氧；对于碳氢化合物，纯度为９９．９９％的即可认为是高纯气体。高纯气体应用领域极宽，在半导体工业，高纯氮、氢、氩、氦可作为运载气、保护气和配制混合气的底气。医用气体（ＭｅｄｉｃａｌＧａｓｅｓ）用于医学诊断和生命救助的气体称医用气体。医用气体包括２０余类，其中主…     

保护气在浮法玻璃生产中的应用

为了保证浮法玻璃质量,防止锡槽内高温锡氧化,必须在窑龄有效期内不断输入按一定比例混合的高纯度氮、氢保护气。对氮、氢气源系统设计了有符合高纯气质量标准的应急供气系统。实践证明,在保证安装质量,严格管道清洗吹扫前提下,采用无缝钢管连续输送氧含量<1×10~(-6)的氮、氢混合气是可行的。     

新型替代制冷剂HFC-32爆炸极限影响因素研究

本文利用可燃性气体爆炸极限测定实验台研究了温度、相对湿度、阻燃剂对HFC-32爆炸极限的影响。结果表明:在-5~55℃范围之内,升高温度会促使HFC-32爆炸上限逐渐增大,其爆炸下限逐渐减少,拓宽了HFC-32的爆炸区间;当相对湿度低于60%时,增大相对湿度会导致HFC-32爆炸下限稍微增大,其爆炸上限稍微减少,当相对湿度由60%逐渐增至87%时,其爆炸上限急剧减少,直至爆炸极限范围消失;添加CF_3I或HFC-134a阻燃剂可促使HFC-32爆炸极限范围减少,而且CF_3I的阻燃效果优于HFC-134a,当CF_3I/HFC-32体积比由0增至1或HFC-134a/HFC-32体积比由0增至10时,两种混合气的爆炸范围最终都减少为0。研究结果为抑制HFC-32燃烧提供了重要的理论依据。     

N_2/CO_2混合气体对丙酮爆炸极限的影响

为了研究N2、CO_2及其混合气体对丙酮爆炸极限的影响,使用爆炸极限测试仪,将气体按一定比例进行混合,从最佳抑爆浓度和抑爆效果两个方面进行分析.结果表明:N2,N2/CO_2体积比为2∶1,1∶1,1∶2混合气体,CO_2对丙酮的爆炸均有抑制作用且最佳抑爆浓度分别为49%,47%,44%,43%,42%;N2/CO_2混合气体中CO_2的含量越高,对丙酮的抑爆效果越好;不同比例的混合气体对丙酮爆炸上限和下限的影响可近似认为是线性变化的;随着N_2,CO_2及其混合气体含量的增加,丙酮的爆炸极限范围减小,丙酮爆炸的危险性降低;当惰性气体增加到一定浓度时,丙酮的爆炸上限和下限重合,其爆炸极限范围可以据此确定.     

硅湿法磷酸体系中不锈钢的冲刷腐蚀研究

采用动态旋转冲刷腐蚀装置，在含硅湿法磷酸体系中，分别考察了不锈钢316L和904L在冲刷条件下浆体的组成、硅砂含量和硅砂粒度对材料冲刷腐蚀速率的影响，并在不同硅含量下讨论了流速对不锈钢的腐蚀规律。试验结果表明，316L以腐蚀为主，当硅砂质量百分含量达10％时，冲刷作用增强；而904L耐液相腐蚀性能优异，但在流速大于4m/s时，硅砂质量百分含量高于3％，粒度大于200μm时，冲刷腐蚀速度增加明显。     

太钢BOC气体有限公司通过ISO9002质量认证

据《中国冶金报》2000年11月21日杨丽英等报道，太钢BOC气体有限公司于2000年10月12日通过ISO 9002质量体系认证，并同时取得质量体系认证证书。太钢BOC气体有限公司是1996年3月成立的中外合资企业，中英双方各持股50％。太钢BOC此次获证覆盖的产品有氧气、氮气、氩气、氖气、氦气、氪气、氙气、氢气、医用氧、灯泡用氩气等及各种混合气的生产，有效期为3年，从2000年10月12日到2003年10月12日。 (本刊)     

乙醇对金属钯复合膜透氢性能影响的研究

利用化学镀的方法制备了不同厚度的钯膜,着重研究了乙醇水蒸气重整反应气氛下钯膜的透氢性能.实验结果表明:573~623K时,乙醇氢气混合气(Et/H2)气氛对钯膜透氢性能的影响大于乙醇水蒸气混合气(Et/H2O)气氛;623~673K时,Et/H2O气氛对钯膜透氢性能的影响大于Et/H2气氛.当钯膜暴露在H2/N2/Et和H2/N2/Et/H2O气氛下50min后,透氢量分别能恢复至初始值的96%和89%.此外,乙醇水蒸气重整反应气氛中,较大的水醇摩尔比[(10~13)∶1]和较薄的钯膜(2~6μm)有利于抑制钯膜透氢量的下降.     

发射场氦气现场提纯技术

液氢贮箱在加注液氢前首先进行氮气置换 ,合格后再进行氦气置换 ,置换后排出的氮氦混合气混合贮存 ,混合气中He纯度为 91 6 6 % ,其余主要为氮气。结合中心现有条件 ,提出了利用高压低温冷凝法和低温吸附法相结合的方法对回收的氦气进行现场提纯 ,可以生产纯度大于 99 995 %的氦气。     

Empirical correlations for the solubility of pressurant gases in cryogenic propellants

We have analyzed data published by others reporting the solubility of helium in liquid hydrogen, oxygen, and methane, and of nitrogen in liquid oxygen, to develop empirical correlations for the mole fraction of these pressurant gases in the liquid phase as a function of temperature and pressure. The data, compiled and provided by NIST, are from a variety of sources and covers a large range of liquid temperatures and pressures. The correlations were developed to yield accurate estimates of the mole fraction of the pressurant gas in the cryogenic liquid at temperature and pressures of interest to the propulsion community, yet the correlations developed are applicable over a much wider range. The mole fraction solubility of helium in all these liquids is less than 0.3% at the temperatures and pressures used in propulsion systems. When nitrogen is used as a pressurant for liquid oxygen, substantial contamination can result, though the diffusion into the liquid is slow.     

Experimental study of flammability limits of natural gas-air mixture

Flammability limits data are essential for a quantitative risk assessment of explosion hazard associated with the use of combustible gas. The present work is to obtain the fundamental flammability data for prevention of the hazards in the practical applications. Experiments have been conducted in a constant volume combustion bomb, and the fuel considered here is natural gas (NG). The pressure histories in the combustion bomb are recorded and a criterion of 7% pressure rise has been used to judge a flammable mixture. The effects of ethane on NG-air flammability limits have been investigated. By adding diluent (carbon dioxide, nitrogen or their mixture) into NG-air mixture, the dilution effects on the flammability limits have been explored as well, and the results are plotted as functions of diluent ratio.     

Experimental investigation of the auxiliary gas circuit of a diffusion absorption chiller with natural and forced circulation

The auxiliary gas circuit has a significant influence on the cooling capacity and the efficiency of a diffusion absorption chiller. Nevertheless, there are only a few theoretical studies and experimental investigations concerning this topic. The reason is the difficulty to gain measurement data of the volume flow rate and the partial pressures without affecting the natural circulation of the auxiliary gas circuit negatively.This paper presents a detailed experimental investigation of the auxiliary gas circuit. The gas mixture in the circuit mainly consists of the vapour of the refrigerant (ammonia) and the inert gas (helium). A clamp-on ultrasonic flowmeter measures the volume flow rate of the gas mixture and the mole fraction of helium and ammonia continuously. The influence of an increasing volume flow on the mass transfer in the auxiliary gas circuit is shown by using a propeller to force the circulation of the gas mixture.     

Carbon dioxide dilution effect on flammability limits for hydrocarbons

Theoretical models to predict the upper/lower flammability limits of a mixture composed of hydrocarbon and inert carbon dioxide are proposed in this study. It is found theoretically that there are linear relations between the reciprocal of the upper/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon/inert gas mixture. These theoretical linear relations are examined by existing experimental results reported in the literature, which include the cases of methane, propane, ethylene, and propylene. The coefficients of determination (R(2)) of the regression lines are found to be larger than 0.959 for all aforementioned cases. Thus, the proposed models are highly supported by existing experimental results. A preliminary study also shows the conclusions in present work have the possibility to extend to non-hydrocarbon flammable materials or to inert gas other than carbon dioxide. It is coincident that the theoretical model for the lower flammability limit (LFL) in present work is the same as the empirical model conjectured by Kondo et al.     

混合工质脉管制冷的热力学性能预测

提出了用于预测混合工质脉管制冷热力学性能的改进型Brayton制冷循环,建立了制冷系统制冷量和制冷系数COP的理论表达式。在对多种低温流体的预测计算的基础上,提出了具有应用潜力的混合工质对。计算结果表明,如果用10%氮与90%氦的混合工质对代替纯氦,脉管制冷机在80K温度下的制冷系数和制冷量分别可以提高9.5%和6.7%。此外还讨论了其它可能用于80K温区脉管制冷的混合工质对,如氢-氦、氩-氦、氖-氦混合物等。     

Mechanical properties of new high strength ferritic iron alloy for cryogenic service

A new high strength, tough iron alloy for cryogenic service has been developed. The new cryogenic structural material does not show unstable cleavage fracture even at 4.2 K and furthermore strength at ambient temperature is higher than 750 MPa. The alloy shows high notch toughness at lower temperature. The impact energy is 229 J at 77 K and 155 J at 4.2 K, which exceeds that of 9% Ni steel. This result encourages the extensive application of ferritic iron alloys to lower temperature regions below 77 K. This new material can also be used for hydrogen and helium liquefied gas containers.     

Two-phase cryogenic flow meters: Part II – How to realize the two-phase pressure drop method

The pressure drop method to find the mass flow rate of the two-phase helium and hydrogen flows is discussed in this paper. This method is based on a combination of the narrowing device and the RF void fraction sensor described earlier. Advantages of this approach with respect to the calorimetric one are demonstrated and its metrological characteristics for different flow patterns are estimated. The discussed cryogenic technologies and methods may be used for others applications, for example, to solve some tasks in oil-producing industry.     

Solubility and stability of barium arsenate and barium hydrogen arsenate at 25 degrees C

International and European dangerous substances and dangerous goods regulations refer to the standard ISO 10156 (1996). This standard includes a test method and a calculation procedure for the determination of the flammability of gases and gas mixtures in air. The substance indices for the calculation, the so called "Tci values", which characterise the fire potential, are provided as well. These ISO Tci values are derived from explosion diagrams of older literature sources which do not take into account the test method and the test apparatus. However, since the explosion limits are influenced by apparatus parameters, the Tci values and lower explosion limits, given by the ISO tables, are inconsistent with those measured according to the test method of the same standard. In consequence, applying the ISO Tci values can result in wrong classifications. In this paper internationally accepted explosion limit test methods were evaluated and Tci values were derived from explosion diagrams. Therefore, an "open vessel" method with flame propagation criterion was favoured. These values were compared with the Tci values listed in ISO 10156. In most cases, significant deviations were found. A detailed study about the influence of inert gases on flammability is the objective of Part 2.