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The present work determines the appropriate inclination angles for each flat tube aspect ratio to increase the thermohydraulic performance without extending the heat exchange area. Furthermore, the amount of entropy generation was investigated to evaluate the exergy destruction for device configuration. A numerical simulation was performed with an inlet air velocity in a range from 3.5 to 5.0 m/s, flat tube aspect ratios (e) from 0.3 to 0.6, and tube inclination angles (β) from 10 to 50°. Analysis results indicated that the highest thermohydraulic performance of configuration e = 0.4 and e = 0.5 was obtained at β = 20°, and for configuration e = 0.3, it was obtained at β = 10−20°. The best thermohydraulic performance for configuration e = 0.6 was obtained at β = 20−30°. The thermohydraulic performance at optimal inclination angles extended from 1.011 to 1.069. The lowest entropy generation occurred at configurations with β = 50°. Increasing the aspect ratio and tube inclination angle increased the Colburn factor, increased the friction factor, and decreased entropy generation.
Luân et al. (Tue,) studied this question.