Mass-Transfer Coefficients for Single Cylinders

Several investigators have studied the sublimation from a solid cylinder into air flowing normal to its axis. Additional results on the dissolution of solid cylinders into a turbulent water stream have been reported. Bedingfield and Drew (1950) correlated the available data, evaluating properties at the average film conditions, by 

From equation (2-9), kQP = ky. However, in this problem, k-type coefficients cannot be used because we are not dealing with dilute solutions. Therefore, we must try to relate the results obtained so far with the F coefficient. We know from equation (2-6) that F=ky yBM. The fact that the correlation in equation (2-73) was developed in terms of kG is evidence that the experimental data used were obtained under very dilute conditions for which yBM- 1.0 and F = ky. Then, we may conclude that F = 6.75 x 10 kmol/m2-s, which is only about 3% higher than the value estimated in Example 2.6 (F = 6.52 x 10 4kmol/m2-s) using an analogy between heat and mass transfer. 

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