Mathematical development of tube loading in horizontal condensers

Equations were derived by Nusselt for condensation on a vertical bank of horizontal tubes employing several questionable assumptions. His theoretical results indicate that the average condensing coefficient for a tube in an n-tube vertical bank should be n−1/4 times the single-tube coefficient. An empirical modification for turbulence previously suggested by the present author changed the factor to n−1/6. To facilitate further experimental studies and design calculations, precise equations are developed for condensate loading for the different common tube layouts bounded by a circle. These equations use a generalized factor n−1/s where a value of s/4 > 1.0 becomes an index of turbulence.