For
the temperatures of 110 and 121.1 ◦C the average heat transfer
coefficients were not significantly different from each other
(p > 0.05 for the Tukey test), but the steam temperature of 132.2
caused a significant (p < 0.05 for the Tukey test) increase in the
average heat transfer coefficient (Fig. 2(c)). For an L/D ratio of
250 the effects of increasing flow rate and steam temperature
were more pronounced because most of the heat was transferred
in the first section of the heat exchanger.