Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8071447 | Energy | 2018 | 8 Pages |
Abstract
In this work we show that the shape of the liquid-vapor saturation curve in a Trâsâ diagram (Trâ¯=â¯T/Tc and sââ¯=â¯s/R, with Tc the critical temperature, s the molar entropy and R the gas constant) for a given fluid is mainly governed by the acentric factor, Ï, and the critical molar volume, vc, of the fluid. The study uses as reference the point M where the saturated vapor curve in the Trâsâ diagram changes its concavity, i.e. (d2s*g/dTr2)M=0. By analyzing the data provided by the National Standards and Technology (NIST) program RefProp 9.1 for 121 fluids, we find that, at this point, TMrâ0.81 and the slope ξM*=(ds*g/dTr)M is well correlated with vc, existing a threshold value vc,0â0.22â¯m3â¯kmolâ1 so that ξM*<0 (wet fluid) for vcâ¯<â¯vc,0 and ξM*>0 (dry fluid) for vcâ¯>â¯vc,0. This direct relation between vc and the wet or dry character of a fluid is the main result of the present work. Furthermore, the dimensionless vaporization entropy at the reference point M, ÎvsM*=sM*gâsM*l, increases in a nearly linear way with Ï.
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Physical Sciences and Engineering
Energy
Energy (General)
Authors
J.A. White, S. Velasco,