Heat transfer and pressure drop characteristics of laminar flow in a circular tube fitted with regularly spaced twisted-tape elements

Saha, Sujoy Kumar; Gaitonde, U.N.; Date, A.W.

doi:10.1016/0894-1777(89)90020-4

Cited by 127 publications

(45 citation statements)

References 3 publications

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“…Saha et al [5] reported that the regularly-spaced twisted tape performed better than the full-length twisted tape at high Reynolds numbers. They concluded that the improved structure could reduce the pressure by 40%.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Friction Characteristics of Turbulent Flow through a Circular Tube with Ball Turbulators

et al. 2018

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Abstract:One of the most commonly used methods of heat transfer enhancement is flow turbulization. This effect can be achieved, e.g., by placing special turbulizing elements into the channel. In this paper, the effects of ball turbulators (BTs) on the heat transfer and fluid friction characteristics in a circular tube are investigated through numerical simulation. The Reynolds number (Re) is in the range of 5000-35,000 under a condition of uniform heat-flux. BTs with different diameter ratios (e.g., 0.5, 0.75, and 1) and spacer lengths (40, 51.77, and 62.5 mm) are inserted in the circular tubes. The results show that the heat transfer rates in the tube equipped with BTs are around 1.26-2.01 times that of those in the plain tube. The BTs with a ball diameter ratio of one provide higher friction factors than 0.75 and 0.5 by about 34.6-46.2% and 51.1-63.4%, respectively. A smaller ball diameter ratio is more able to decrease the friction factor. The performance evaluation criterion (PEC) data indicate that the use of a smaller ball diameter ratio (BDR) and a smaller spacer length are preferred. The results also reveal that BTs with a larger diameter ratio and a smaller spacer length yield the highest heat transfer rate as well as the largest pressure loss. Compared with the plain tube, the fluid flow velocity near the tube wall is significantly improved when BTs are used at the same Reynolds number.

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Section: Introductionmentioning

confidence: 99%

Heat Transfer and Friction Characteristics of Turbulent Flow through a Circular Tube with Ball Turbulators

et al. 2018

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“…He found that on the basis of unit pumping power and unit pressure drop half-length twisted tape is more efficient than full length tape. Shaha and Chakraborty [4] found that laminar flow of water (145<Re<1480, 4.5<Pr<5.5, tape ratio 1.92<y<5.0) and pressure drop characteristics in a circular tube fitted with regularly spaced, there is drastic reduction in pressure drop corresponding reduction in heat transfer. Thus it appears that on basis of constant pumping power a large number of turn may yield improved thermo hydraulic performance compared with single turn on twisted tape.…”

Section: Introductionmentioning

confidence: 99%

Review of Heat Transfer Augmentation by Using Twisted Tape Insert in Laminar Region

2017

IJAERD

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“…Patil [8] researched with varying width twisted-tape inserts with both friction factor and Nusselt number is lower than those with full-width twisted tapes. Saha et al [9,10] have implemented regularly spaced twisted-tape elements which are much better than full-length twisted tapes under certain circumstances. Li et al [11] have introduced an optimal multi-layer spacer with non-woven nets in the outer layers and twisted tapes in the middle layer.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Heat Transfer Enhancement through a Circular Duct Fitted With Centre-Trimmed Twisted Tape

Bhattacharyya¹,

Chattopadhyay²,

Bandyopadhyay³

2016

IJHT

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Twisted tape is a widely used technique for heat transfer enhancement. In the present study, the influences of centre-trimmed twisted tapes (CTTT) on heat transfer rate, friction factor and thermal enhancement efficiency were numerically investigated. The centre-trimmed twisted tapes were used as swirl flow generators inside the circular duct. Investigations were performed in the Reynolds number range of 100 -5,000 with four different centre-cleared twin twisted tapes at twist ratio (TR) of H/W = 1.0, 2.0, 3.0 and 4.0. The governing equations are solved with a finite-volume-based numerical method. A three-dimensional non uniform grid was generated, in order to critically examine the flow and heat transfer. Results show that the centre-cleared twin twisted tape causes considerable enhancement of heat transfer when compared with plain twisted tape (TT). The enhancement over standard twisted tape increases with the increase of Reynolds number. The improved parameter is observed in the range of Reynolds number below 800 and also above Re 4000 for all TR, though the best performance is found at TR = 1.0 and 3.0

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Heat transfer and pressure drop characteristics of laminar flow in a circular tube fitted with regularly spaced twisted-tape elements

Cited by 127 publications

References 3 publications

Heat Transfer and Friction Characteristics of Turbulent Flow through a Circular Tube with Ball Turbulators

Heat Transfer and Friction Characteristics of Turbulent Flow through a Circular Tube with Ball Turbulators

Review of Heat Transfer Augmentation by Using Twisted Tape Insert in Laminar Region

Numerical Study on Heat Transfer Enhancement through a Circular Duct Fitted With Centre-Trimmed Twisted Tape

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