TRANSPORT PROPERTIES OF DICHLORODIFLUOROMETHANE IN THE TEMPERATURE RANGE OF 280-450 K

Thermal conductivity of research grade pure dichlorodifluoromethane is measured in the temperature range 280-450?K employing the thermal conductivity column method. These data are compared with the most probable recommended values based on several data sets which scatter appreciably from each other. The molecular kinetic theory in conjunction with the Lennard-Jones (12-6) potential is employed to predict all the three transport properties of this gas. The inter-relations between the kinetic theory expressions for the viscosity and diffusion coefficients, which are essentially independent of the choice of intermolecular potential, are also used to predict these two properties.     

TRANSPORT PROPERTIES OF DICHLORODIFLUOROMETHANE IN THE TEMPERATURE RANGE OF 280-450 K

Thermal conductivity of research grade pure dichlorodifluoromethane is measured in the temperature range 280-450 K employing the thermal conductivity column method. These data are compared with the most probable recommended values based on several data sets which scatter appreciably from each other. The molecular kinetic theory in conjunction with the Lennard-Jones (12-6) potential is employed to predict all the three transport properties of this gas. The inter-relations between the kinetic theory expressions for the viscosity and diffusion coefficients, which are essentially independent of the choice of intermolecular potential, are also used to predict these two properties.     

氮化铝的室温热导率

本文导出了氮化铝室温热导率的一般表达式，对提高氮化铝陶瓷材料室温热导率的途径作了讨论。     

EXPERIMENTAL MEASUREMENTS OF FOAMING TENDENCIES IN AQUEOUS GAS SWEETENING SOLUTIONS CONTAINING MDEA OVER A TEMPERATURE RANGE OF 297-358K AND A PRESSURE RANGE OF 101-500KPA

This work presents experimental measurements of foaming tendencies and break times for 50 wt% aqueous solutions of MDEA in contact with nitrogen, methane, and ethane gases from atmospheric pressure to 500 kPa and temperatures from 297 to 358 K. The effect of various contaminants including methanol, HEP (1,4- bis-2-hydroxyethyl piperazine), hexane, and carboxylic acids ranging from formic to dodecanoic acid was investigated. Only those systems containing carboxylic acids heavier than valeric acid exhibited foaming. Foaming tendency in systems containing carboxylic acids was worsened by the addition of methanol and HEP, although the difference was moderate. Foaming was shown to be worse at lower pressure and at higher temperature. Foaming in MDEA systems was shown to be substantially worse than that measured previously by McCarthy and Trebble (1996) for aqueous systems of DEA.     

液体的导热系数与蒸发潜热及温度间的关系

提出了流体导热系数的自由体积模型,用方阱流体的分子动力学模拟结果验证了模型,获得满意的结果.将所得模型结合统计力学理论,导出了液体的导热系数与蒸发潜热间的关系,对40种有代表性的物质(569个点)的关联,误差仅为1.78%,最后得到关联导热系数与温度的两参数模型,对40种物质的关联结果表明,所得模型适用于直到临界点附近的宽广的温度范围,优于被认为较成功的Jamieson的两参数经验式.     

TEMPERATURE MEASUREMENT ERROR BY RADIAL INSERTION OF THERMOCOUPLE IN THERMAL CONDUCTIVITY MEASURING DEVICE

To measure the temperature of the inner part of a material, an axially inserted thermocouple is often used. But, when the measurement by an axially inserted thermocouple is difficult, we must insert the thermocouple radially. In the case of radial insertion, a measuring error usually exists. To know the true temperature by the method of radial insertion of a thermocouple, we must conduct numerical calculations.

In this report, numerical calculations have been conducted for the temperature measuring error by radial insertion of thermocouple in a gas thermal conductivity measuring device.^2-5     

TEMPERATURE MEASUREMENT ERROR BY RADIAL INSERTION OF THERMOCOUPLE IN THERMAL CONDUCTIVITY MEASURING DEVICE

To measure the temperature of the inner part of a material, an axially inserted thermocouple is often used. But, when the measurement by an axially inserted thermocouple is difficult, we must insert the thermocouple radially. In the case of radial insertion, a measuring error usually exists. To know the true temperature by the method of radial insertion of a thermocouple, we must conduct numerical calculations.

In this report, numerical calculations have been conducted for the temperature measuring error by radial insertion of thermocouple in a gas thermal conductivity measuring device.^2-5     

岩矿棉隔热材料导热系数与密度及温度的关系

用稳态法研究岩矿棉隔热材料热系数与密度及温度的关系，结果表明，在一定的工艺条件下，对于化学组成稳定确定的岩矿棉隔热材料，在一个大气压及确定的温度下，在８０－１００ｋｇ／ｍ＾３的密度范围将出现导热系数最小值；其导热系数随着温度的增加而非线性地增大，并从理论上提高其经济性的途径，这为陶瓷窑炉保温结构的热设计提供了科学依据。     

THE THERMAL CONDUCTIVITY OF SOME REFRACTORIES1

The problem of measuring the thermal conductivity of materials up to high temperatures has been studied, especially in regard to the sources of error. This investigation has shown that many of the previous determinations of thermal conductivity may have had little precision due to a lack of appreciation of the errors involved. The values of thermal conductivity for a number of refractories are given, as obtained by a new type of apparatus designed to eliminate to a considerable extent the errors of measurement. However, it is believed that these values may have an error as high as ± 25 % for the better heat conductors; so there is still much work to be done in developing a method for measuring thermal conductivity with the precision usual in other physical measurements.     

THE THERMAL CONDUCTIVITY OF CARBORUNDUM REFRACTORIES1

Thermal conductivity measurements up to 1350°C of silicon carbide refractory materials have been made, using the water calorimeter method. Data were secured on furnace walls such as those commonly used in practice and results are believed to be accurate to within about 1%. Conductivity measurements were made on seven carborundum single walls and on eight carborundum-fire-clay composite walls. The relation of the thermal conductivity to temperature, chemical composition, and porosity was investigated, as well as the magnitude of the surface and joint effects. The conductivity of carborundum was found to vary with the quantity of heat energy transmitted through the wall. Tables are given showing the coefficients of thermal conductivity and heat flow through various types of walls with a temperature of 1500°C in the combustion chamber. Temperature gradient charts and heat flow curves for various walls are also given together with the practical application of the results in the design of commercial furnaces.     

热梯度法化学气相渗温度控制

建立了热梯度法化学气相渗工艺（ＣＶＩ） 模型,计算了圆筒炭毡内的温度分布,给出热梯度法ＣＶＩ 工艺沉积温度的控制方法。利用这种方法,采用热梯度法ＣＶＩ 工艺,在１００ ｈ 之内成功地制备出内径１６０ ｍ ｍ 、高３９０ ｍ ｍ 、厚２０ｍ ｍ 的圆筒炭毡增强Ｃ／Ｃ 复合材料,密度达到１ ．６ ｇ／ｃｍ ３ 。     

THERMAL CONDUCTIVITY OF THF CLATHRATE HYDRATE FROM 243 K TO 263 K

Using transient plane source technique, we measured THF hydrate thermal conductivity from 243 K to 263 K. The sample THF solution is over saturated in order to avoid the effect of ice. And also to avoid the effect of crystal anisotropy, the THF hydrate was crushed to measure. In the test temperature value increases with the temperature increasing.     

MEASUREMENT OF THE THERMAL CONDUCTIVITY OF FIRELAY REFRACTORIES*

Thermal conductivity determinations have been made on superduty fire-clay, silica, and kaolin refractories, using the Globar-heated, water calorimeter apparatus previously described. The arrangement, which is satisfactory for insulating firebrick, gives considerable error when firebrick samples are tested. Results obtained by different arrangements of the guard samples and heating elements are shown as well as a final arrangement which gives a satisfactory condition of parallel heat flow.     

液氨温度对高压氨泵及其电机的影响

计算了在不同的液氨温度下高压氨泵的出口压力和电机的电流，并对适当提高入口液氨温度后泵的机封和电机的节约情况进行了估算。     

窑法磷酸旋窑操作温度范围的试验研究

窑法磷酸旋窑操作温度范围的试验研究邱礼有，江礼科（成都科技大学化工系，成都６１００６５）关键词：旋窑，操作温度，熔点，磷矿还原１前言窑法制造磷酸新工艺是７０年代提出来的。它具有不用酸，不用电加热，能充分利用磷和ＣＯ的氧化热，可以用中低品位磷矿制取低成...     

PREDICTION OF THERMAL CONDUCTIVITY AND VISCOSITY FOR SOME FLUIDS IN THE NEAR-CRITICAL REGION

The objective of this work was to develop general, simple and accurate expressions to predict the peculiar behavior of thermal conductivity and viscosity in the near-critical region. Expressions were determined for (a) variation of thermal conductivity as a function of temperature and density or pressure for carbon dioxide, water, and ammonia, and for (b) variation of viscosity as a function of temperature and density or pressure for carbon dioxide, water, and nitrogen. The predicted results based on the developed expressions showed a very good agreement with the available thermal conductivity experimental data and an excellent agreement with the available viscosity experimental data     

合成氨装置电导率监测仪典型故障及处理

介绍合成氨装置冷凝液电导率监测仪的典型故障和现象,从故障现象分析、现场仪表和DCS间的通信应用及故障处理方法等方面进行剖析,阐述现场分析仪表的典型故障处理经验。     

聚合物基复合材料导热模型及其研究进展

本文对聚合物基复合材料的各种导热模型进行了归纳和总结,包括理论性和经验性的模型。模型描述是多方面的,包括粒子填充型、纤维填充型、纤维布增强型等,并做出评价,提出应用过程中的一些建议。