Among molten salts, alkali carbonates are important and expected to many kinds of industrial applications for high temperature use. So, their thermophysical properties are required for analysis of energy-related researches and designs. We have developed a measuring method of specific heats of both solid and molten phases, and latent heat of fusion. Previously, we reported the measurements on Li2CO3, Na2CO3, K2CO3 and their eutectic mixtures. In present study, the properties of single salts, Rb2CO3 and Cs2CO3, and of seven kinds of ternary eutectic salts containing alkali carbonates were obtained. Melting temperatures of these ternary salts were ranging from 670K to 890K. Most of the data of specific heats and heats of fusion of the molten salts presented here were not found in any other literature.
Total emittance behavior of thermal radiation is investigated experimentally on ash deposit layers in a power-plant boiler system far lowquality coal powder combustion. The total emittances are measured at 570-1270K. The deposit layers of more than 1mm in thickness are found to be diffuse and opaque for the infrared radiation. The emittances range from 0.5 to 0.9. The emittances decrease with an increase in temperature, while the pulverized deposit layers which are sintered at higher than 1000K show a clear hysteresis phenomenon of the emittance. The emittances of the sintered layers are much higher than those of the unsintered layers.
A detailed knowledge of the physical properties of molten metals and slags (fluxes, glasses) is required for a clear understanding of any molten metal/slag processing operations. This is especially true for manufacture of materials of higher chemical and physical quality. This paper has served to introduce some equations for predicting densities and viscosities, which are indispensable basic properties, of molten metals and slags at high processing temperatures. More reliable and accurate experimental data for the densities and viscosities of various molten metals and slags are needed so as to test and develop equations and to predict reasonable values for the properties.
This paper describies present situation and some problems about measuring methods of thermal properties of building materials, based on JIS. The actual heat transfer within them may be involve a complex combination of different contributions of radiation, conduction and convection. For such materials, heat transfer property, very ofen wrongly called “thermal conductivity”. This property, in accordance with ISO, should be called “trasnsfer factor”. Measuring methods are Guarded hot plate method, comparison method and heat flow method. Building construction is assembled with some materials. The total amount of heat transfers from one side of thus constructions to the other for a given temperature difference. There are method such as the Calibrated hot box and the Guarded hot box method. The standard sample should be needed to measure exactly the heat flow rate. Japan Testing Center for Construction Materials has proposed a kind of standerd materials, silicone rubber, but it needs to other kind of standerd materials, especially for low thermal conductivity materials.
The multilayer insulator (MLI) for superconducting devices has been studied. The structure of cryostat, materials of MLI, calculation methods of insulator performance, and some experimental results are refered. Facters which influence insulator performances has been revealed.