Momentum, Heat, and Mass Transfer Analogy for Turbulent Flow in

10

Parenthetically, a trial and error application of model 2-4 by Hughmark was said to suggest a division between the resistance within t h e wall region (given by Equation 4) and the boundary layer region of y + = 0.45. Hence, it appears that the mean approach distance A + used in model 2d must be less than or equal to 0.45. I n contrast, experimental data by Popovich and Hummel suggest a mean approach distance of h+ equal to 5.05. In conclusion, models 1 and 2 apparently underpredict experimental heat and mass transfer data for large values of the Schmidt number due to the assumption that no external mixing takes place. I n regard to model 2A, it is felt that Hughmark’s formulation is unduly artificial. Further, some question arises concerning the ability of the model to correlate experimental data for fluids with high values of the Schmidt number.

RANDOM

3 rc.

1

UNIFORM

0.I

Nomenclature

I I

0.I

10

”+I

I It

A=[A+, Js,

s