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On a reduced equation for gaseous diffusivity
Author(s) -
Ramamurthy A. V.,
Narsimhan G.
Publication year - 1970
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450480313
Subject(s) - thermal diffusivity , thermodynamics , binary number , chemistry , analytical chemistry (journal) , physics , mathematics , chromatography , arithmetic
The application of the theorem of corresponding states to the HBS equation for binary diffusivity has resulted in the formulation of the following two generalized equations T ≤ 1.875( T CA T CB ) 1/2 D AB (1 + α) 2 ṁ M r ṁ T CB 3/13 ṁ P CA 1/3 / T CA 1.07 = 3.65 × 10 −4 ṁ T RA 2 /( Z CA ) 2/3 ṁ P RAT ≥ 1.875 ( T CA T CB ) 1/2 D AB (1 + α) 2 ṁ M r ṁ T CB 1/12 ṁ P CA 1/3 / T CA 0.92 = 6.45 × 10 −4 ṁ T RA 5/3 /( Z CA ) 2/3 ṁ P RA A critical diffusivity ( D c ) AB has been defined based on the above equation ( D c ) AB = T CA (5/6 + n )/ T CB n ṁ P CA 1/3 ṁ M r (1 + α) 2 This equation has a form similar to one defined by Reid and Sherwood. After testing the two equations with diffusivity data for 25 systems, it is found that the average error of prediction is about ± 5.0%. The error of prediction with the second equation is only 3.0%. The diffusivity equations have been shown to provide a satisfactory “reference substance” technique for estimation of binary diffusivity data.