Turbulent mixed convection in heated vertical channel

Abstract

In this paper an investigation of mixed convection from vertical heated channel is undertaken. The aim is to explore the heat transfer enhancement obtained by adding a forced flow, issued from a flat nozzle located in the entry section of a channel, to the up-going fluid along its walls. Combined forced and free convection are studied in order to increase the cooling requirements. The study is conceded for two Rayleigh number. The first case corresponds to two separate boundary layers so the channel acts as two independent plates. For the second case the two boundary layers are attached. Calculations are carried out with air as the working fluid by changing the jet velocity in order to optimize the system to give the maximum heat flow rate over the chimney. The system of governing equations is solved with a finite volumes method and an implicit scheme. The results obtained show that the jet-wall activates the heat transfer, as does the drive of ambient air by the jet.