Numerical investigation of heat transfer and aerodynamics of single drop-shaped tubes

Flow and heat transfer from a single drop-shaped and circular tubes in crossflow is studied numerically for the Reynolds numbers varying from 1.5·10 3 to 26.5·10 3 . These tubes have axis ratios of L/D = 1, 1.5, 2, 2.5, 3, 3.5, and 4, when L/D = 1, the tube is circular. The distribution of local coefficients of heat transfer α, pressure C p , and friction C f over a half of the tube surface is presented. The maximum value of C f gradually increases with the increase of L/D. Simulated results agree well with those available in the literature. Correlations of the average Nusselt number and a friction factor in terms of the Reynolds numbers and axis ratios for the studied tubes were proposed. Drop-shaped tubes have a lower pumping power to provide the same heat transfer compared to a circular one under the same operating conditions. The thermo-hydrodynamic characteristics of the drop-shaped tube with L/D = 4 are better as compared to other studied tubes.