ISSN Online: 2377-424X
ISBN Print: 0-89116-909-1
International Heat Transfer Conference 9
FLOW RATE PREDICTIONS FOR A THERMOSYPHON LOOP
Sinopsis
A theoretical investigation of steady−state thermosyphoning in a closed−loop comprising two vertical tubes joined by upper and lower plenums has been undertaken. The equations governing two−dimensional developing laminar combined natural and forced convection in the heated and cooled sections were solved, by a finite−difference method, to provide pressure differences required for the thermosyphon problem. Numerical results obtained for water (Pr = 4.3) flows in loops with different source−to−sink elevation differences, at various Grashof numbers, confirm that buoyancy strongly influences the shape of the developing axial velocity profile, and hence the wall friction. The axial variation of the average cross−section temperature causing the buoyant driving force is explained. A comparison of the results, including flow rate predictions, is made with conventional one−dimensional analysis.