ISSN Online: 2377-424X
ISBN Print: 0-89116-559-2
International Heat Transfer Conference 8
COMBINED FREE AND FORCED CONVECTION IN A VERTICAL AND INCLINED CYLINDRICAL ANNULUS
Résumé
An experimental investigation is reported of superposed free and forced convection in an internally heated concentric annulus in vertical, inclined and horizontal position. Both upflow and downflow are considered in the concentric annulus having an equivalent diameter of 16 mm and a heated core of 1 m length. Reynolds number ranges from 350 to 20 000, Grashof number from 105 to 108, and Prandtl number from 2.3 to 75. The results show an increase of Nusselt number in the regime of laminar flow and combined convection. As the annulus inclination deviates from vertical, the Nusselt number changes. Characteristic values of Rayleigh and Reynolds numbers describe this effect. In the case of turbulent flow Nusselt number decreases with ratio of Grashof-to-Reynolds number and with angle of inclination. The measured heat transfer data are also presented in form of correlation equations.