MEASUREMENT OF THE GASEOUS DIFFUSION COEFFICIENT OF DIETHYL ETHER INTO AIR BY THE STEFAN METHOD
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Accession number;07A0043236
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| Title;MEASUREMENT OF THE GASEOUS DIFFUSION COEFFICIENT OF DIETHYL ETHER INTO AIR BY THE STEFAN METHOD |
| Author;
MATSUNAGA NAOKI
(Takushoku Univ., Fac. of Eng.)
HORI MORIO
(Takushoku Univ., Fac. of Eng.)
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Journal Title;Thermophys Prop
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Journal Code:X0031A
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ISSN:0911-1743
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VOL.27th;NO.;PAGE.101-103(2006)
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| Figure&Table&Reference;FIG.5, REF.8 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;An apparatus has been developed for measuring the diffusion coefficients of vapors into gases by the Stefan method and the diffusion coefficient of diethyl ether (DEE) vapor into air has been measured at 25.DEG.C. and at atmospheric pressure. The aim of the present study is twofold; to determine the diffusion coefficient of the DEE-air system and to find out the optimum experimental conditions. The apparatus is shown in Figure 3. The sample liquid (DEE) was contained in the vertical evaporation tube made of Pyrex (i.d. 4mm, o.d. 6mm, length ca. 250mm). Vapor from the sample liquid meniscus diffused upward in the diffusion path between the meniscus and the open end of the tube. A stream of the sample gas (air) passed over the open end of the evaporation tube and removed the vapor. The diffusion path length L was measured by a travelling telescope. When the vapor concentration at the open end of the tube is effectively zero, the diffusion coefficient of the vapor-gas system can be obtained from the rate of increase in the diffusion path length L due to evaporation loss of the sample liquid with the aid of Eq. (1) (Figure 1). The diffusion coefficient D of the DEE-air system has been measured with L=80, 120 and 160mm. The most probable value of D in this study, obtaind in the air flow rate range Q around 200-900cm'3'min'-1', is 0.91cm'2's'-1' (Figure 4). This value agrees well with our experimental data obtained by the Taylor dispersion method (Figure 5). Although the diffusion path lengths L.GEQ.80mm seem to be suffcient with the present results, the result with L=80mm is found to be unsatisfactory at 30.DEG.C. (data not shown here). The value of L should carefully be determined for each system and each temperature used. The optimum air flow rates Q are rather high. However, a number of studies have been done with low gas flow rates (below 100cm'3'min'-1'). (author abst.) |
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