Laminar convective heat transfer with twisted tape inserts in a tube

CFD Analysis of a Pipe Equipped with Twisted Tape

“…The insertion of this type of turbulator introduces a swirl motion, which increases the kinetic energy of the flow that means it can be defined as pseudo-laminar, as confirmed by Sarma et al [1]. The resolution of the flow field, for low Reynolds numbers, through a two-equations turbulence model (k-ω), provides the same results obtained by using the laminar model.…”

“…The increase in the convective heat transfer coefficient owing to the use of twisted tapes causes the superimposition of five effects [1]. These effects are: the increase in velocity due to the partitioning of the flow, the reduction of the hydraulic diameter, the increase of the flow path due to the presence of the tape, the generation of a secondary flow due to the spin induced by insert and, in the case of good contact between the insert and wall pipe, the fin effect.…”

An Experimental Study on Heat Transfer and Friction Factor of Al2O3 Nanofluid

“…The procedure is repeated with tapes of different twist ratios: 5, 10, and 15. The equation (Sarma et al, 2003) based on theoretical analysis and obtained with a standard deviation of 4% and average deviation of 3% for the estimation of the Nusselt number, is given by:…”

“…Passive enhancement of heat transfer can also be achieved with the use of twisted tape inserts for flows in a tube or duct. Heat transfer enhancements have been determined through experiment and numerical analysis for the flow of single-phase fluids in a tube, which are valid for a wide range of Reynolds number (Smithberg & Landis, 1964;Lopina & Bergles, 1969;Lecjaks, Machac, & Sir, 1987;Sarma, Subramanyam, Kishore, Dharma Rao, & Kakac, 2003). Experiments have determination the heat transfer using twisted tape inserts in a tube with Al 2 O 3 nanofluid at different volume concentrations (Sharma, Sundar, & Sarma, 2009;Sundar & Sharma, 2010).…”

Experimental Investigation on Turbulent Heat Transfer, Nusselt Number and Friction Factor Characteristics of Square Ducts

“…Saha and Langille [15] (2002) reported heat transfer and pressure drop characteristics of laminar flow through circular tube with longitudinal strip inserts under uniform wall heat flux. Sarma [16] (2003) studied Laminar convective heat transfer with twisted tape inserts in a tube, new method is postulated to predict heat transfer coefficients with twisted tape inserts in a tube. Yadav [17] (2009) studied influence of the half length twisted tape insertion on heat transfer and pressure drop characteristics in a U bend double pipe heat exchanger An experimental investigation on turbulent heat transfer and friction loss behaviors of airflow through a constant heat-fluxed channel fitted with different heights of triangular ribs was conducted by Thianpong et al [18] with AR = 10 and height H = 30 mm with three uniform rib heights, e = 4, 6 and 8 mm and one non-uniform rib height e = 4, 6 mm alternately for a single rib pitch p = 40 mm.…”