Comparison between the heat transfer coefficient for rough
plate and that obtained from rough surface micro channel [14]
under the similar roughness is shown in Fig. 7. The trend of rough
plate data is similar to that of rough surface micro channel.
However, heat transfer coefficient of rough plate is higher than
rough surface micro channel about 3.71 times. Based on the data
in this study, the Nusselt number correlation for water flowing
through the plate heat exchanger with rough surfaces is presented
for practical applications.It is found that the mean absolute deviation between measured
results and proposed correlation is 1.21%.