Effect of inlet velocity profile on heat transfer in a rotating channel

The effects of the inlet velocity profile on the heat transfer coefficient in rotating smooth and angle ribbed channels were experimentally investigated. The detailed heat transfer coefficient was measured using the transient liquid crystal technique. Reynolds numbers based on the channel hydraulic diameter of 10,000, 20,000, and 30,000 were tested, and the corresponding rotation number ranged from 0.067 to 0.184. Results showed that the Nusselt number ratio decreased as the Reynolds number increased for both channel cases, and the Nusselt number for the trailing surface is the highest for both channel cases. For the smooth channel case, the Nusselt number for the leading surface is higher than that for the stationary surface, while the reverse trend was observed for the ribbed channel. An inlet velocity profile with a higher centerline velocity resulted in higher heat transfer for the smooth channel, but the skewed inlet velocity profile caused higher heat transfer for the ribbed channel.