Heat transfer and turbulent flow friction in a circular tube fitted with conical-nozzle turbulators

On the role of inserts in forced convection heat transfer augmentation

“…With the incorporation of insert, the friction factor experimental results coincide with those of the plain channel. It was observed in some of the previous studies that the friction factor with insert is higher than that of a plain channel [9,[36][37][38][39][40]. The present results are distinct due to the fact that the insert is placed upstream of the test section and the turbulent flow is hydrodynamically fully developed before entering the test section.…”

Thermal performance evaluation of heat exchangers fitted with twisted-ring turbulators

“…It was found that the turbulators considerably enhanced heat transfer and friction factor over those of the plain tube. Heat transfer augmentations attributed to several types of V-nozzle/conical turbulators and snail with/without free-spacing entry were reported by Eiamsa-ard and Promvonge [4,5] and Promvonge and Eiamsa-ard [6][7][8][9]. Kongkaitpaiboon et al [10] evaluated performances of the perforated conical-ring turbulators with different perforation diameters and perforation numbers.…”

Convective Heat Transfer and Thermal Performance in a Circular Tube Heat Exchanger Inserted with U-Shaped Baffle

“…They reported that the heat transfer augmentation is around 57-195% when compared with the smooth circular tube without vortex generator. The selection of the conical-ring to improve the heat exchanger was also reported by many researchers (Yakut and Sahin, 2004a;2004b;Durmus, 2004;Eiamsa-ard and Promvonge, 2006a;2006b;Promvonge and Eiamsa-ard, 2007a;2007b;2007c;2007d;Kongkaitpaiboon et al, 2010b;Ozceyhan et al, 2006;Akansu, 2006;Kiml et al, 2003;2004). They found that the conical-ring in the heat exchanger enhances heat transfer rate and thermal efficiency, but also increases very large pressure loss, especially, at low diameter ratio (low flow area).…”