Developing flow of FC-72 in a uniformly heated horizontal cylindrical pipe was studied in the regime of transitional mixed convection. Heat transfer coefficients were measured at 6 cross sections along the heated length, with 60 azimuthal positions being monitored at each section. Tests were conducted at 6 different flow rates and 3 imposed heat fluxes. A significantly different thermo-fluid-dynamic behaviour was observed between top and bottom of the pipe. A single Nusselt number correlation was proposed for the entire heat transfer surface, best fitting the 5760 experimental points with only 7 parameters. The conceptual evolution to the final expression of the correlation is shown. The maximum deviation from the measurements is 17.5%, with a 3% average.
Transitional Mixed Convection in the Entrance Region of a Horizontal Pipe
TESTI, DANIELE
2008-01-01
Abstract
Developing flow of FC-72 in a uniformly heated horizontal cylindrical pipe was studied in the regime of transitional mixed convection. Heat transfer coefficients were measured at 6 cross sections along the heated length, with 60 azimuthal positions being monitored at each section. Tests were conducted at 6 different flow rates and 3 imposed heat fluxes. A significantly different thermo-fluid-dynamic behaviour was observed between top and bottom of the pipe. A single Nusselt number correlation was proposed for the entire heat transfer surface, best fitting the 5760 experimental points with only 7 parameters. The conceptual evolution to the final expression of the correlation is shown. The maximum deviation from the measurements is 17.5%, with a 3% average.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
