Experimental study of forced convection from helical coiled tubes with different parameters
2011
Moawed, M.
The forced convection from outside surfaces of helical coiled tubes is studied experimentally with a constant wall heat flux. Ten helical coiled-tubes of different parameters with a range of diameter ratio (D/dₒ) ranged from 7.086 to 16.142 and pitch ratio (P/dₒ) ranged from 1.81 to 3.205 are employed in the present study. The experiments are performed in an open-circuit airflow wind tunnel system operated in suction mode. The experiments covered a range of Reynolds number (Re) of 6.6×10² to 2.3×10³. The experimental results indicated that these parameters (D/dₒ and P/dₒ) have important effects on the average heat transfer coefficient. The average Nusselt number (Nuₘ) increases with the increase of D/dₒ at constant Re and P/dₒ. Also, Nuₘ increases with the increase of P/dₒ at constant Re and D/dₒ. A considerable agreement between the present experimental data and previous work is achieved. The average Nusselt numbers is correlated with Re, D/dₒ and P/dₒ.
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