Turbulent convection in round tube equipped with propeller type swirl generators

Experimental and numerical study on heat transfer enhancement in a channel with Z-shaped baffles

“…Therefore, many engineering techniques have been developed for enhancing the rate of convective heat transfer from the channel surface for decades. Periodic flow interruption generated by ribs [1], baffles [2][3][4], grooves [5], helical or twisted tape [6,7], propeller [8] and winglets [9] is an extensively used means for augmentation of heat transfer in the heat exchangers. The rib/baffles increase not only the degree of heat transfer coefficients by restarting the thermal boundary layer after flow reattachment between rib/baffles but also the pressure drop due to the decreasing flow area effects.…”

Prediction of heat transfer and flow characteristics in helically coiled tubes using artificial neural networks

“…Heat transfer processes are widely used in a variety of industrial applications and heat transfer enhancement (HTE) methods are subject of many recent investigations [1][2][3]. Hence, reliable prediction methods are absolutely essential for design appropriate industrial equipments such as heat exchangers.…”

Heat transfer characteristics and friction of turbulent swirling air flow through abrupt expansion

“…Due to the enlargement in the diameter of the pipe, ∆P may have a negative or positive value according to the investigated independent parameters. The enhancement efficiency η is defined as the ratio of the heat transfer coefficient for the inserted tube h m to that for plain tube h o at same pumping power and it may be more than unity according to ref [19].…”

“…They found that; using more than one propeller vane gave results better than using a full length twisted strips. They also found that Nusselt number and efficiency increased with vane angle decreasing, except for Eiamsa-ard et al [19] who found that the efficiency and the heat transfer increased with vane angle increase. Numerical studies for turbulent swirling flow characteristic through sudden pipe expansion were done by Vanierschot and Bulck [20], who found that the reattachment length for swirling flow through sudden expansion depends on the swirl number, expansion ratio and the reattachment length at zero swirls.…”