A change in the hydraulic diameter due to fouling influences the local heat transfer coefficient h in a heat exchanger with constant m, L, A, and fluid properties as follows: (a) h increases linearly...

A change in the hydraulic diameter due to fouling influences the local heat transfer coefficient h in a heat exchanger with constant m, L, A, and fluid properties as follows:

(a) h increases linearly with an increase in Dh.

(b) h is inversely proportional to Dh.