Buoyancy effects on opposing laminar flow in a uniformly heated inclined cylinder

Abstract EN

Experiments have been performed to investigate mixed convection heat transfer in the thermal and hydrodynamic entrance region of a uniformly heated inclined tube.

The effects of surface heat flux, Reynolds number, the direction of main flow relative to secondary flow (opposing flow), and angle of tube inclination on the temperature distribution and local Nusselt number along tube were studied.

The study covered Reynolds number range (450≤ Re ≤2008), and heat flux range (95 ≤ q ≤898) W/m2, Rayligt number from 1.1132105 to 3.6982105 and angle of inclination α=0° (Horizontal), α=30°, α=60° (Inclined), α=90° (Vertical).Results show that the heat transfer process improve whenever move angle of inclination from vertical position to horizontal position .

The experimental data were correlated for Num as a function of Ram &Rem for each angle of inclination and then superimposed the angle of inclination α to give a general equation of average Nusselt number at any α in opposing flow.