Table 2 Summarises the most important twisted tape investigations that began in laminar flow
From: Assessment of twist tape thermal performance in heat transfer passive augmentation technique
Author | Working fluid | NRe | NPr | Twist tape geometry | Remark |
|---|---|---|---|---|---|
Hong and Bergles [36] | Water, ethylene glycol | Water—NRe, 83–2460; Ethylene Glycol- NRe, 13–390 | Water—NPr, 3–7 Ethylene Glycol-NPr, 84–192 | Full length twist tapes | Friction is affected by tape twist when at high NRe |
| Â | Â | Â | Â | Â | Nusselt is 9 times that tube without twist tapes |
Saha et al. [38] | – | NRe 45–1150 | NPr 205–518 | Twisted tapes regularly spaced with twisted tapes ratio 2.5–5 | In terms of thermo-hydraulic efficiency, pinching twisted tape outperforms connecting thin rod |
Agarwal and Raja Rao [83] | Viscus fluid (Servothe rm oil) | NRe 70–4000 | NPr 195–375 | Twisted tapes inserts with twist ratio 2.41–4.84 | The friction factor increased by 3.13–9.71% |
Ray and Date [37] | Water | NRe 100–3000 | NPr < 500 | Full-length twisted tape have width equal to side of duct | Square ducts have better hydrothermal efficiency than circular ducts |
Klaczak [41] | Water | NRe 110–1500 | – | Twisted tape insert (in air cooled vertical copper pipe) with twist ratio 1.62–5.26 | When the pitch of twisted-tapes was the lowest, effectiveness was at its peak |
Kapatkar et al. [84] | Water | NRe 200–2000 | – | Twisted tapes with twist ratio 5.2–3.4 | Stainless steel, insulated, and aluminium strengthen NNu |
Wang and Sunden [39] | Water, Ethylene glycol | NRe 300–30,000 | Water NPr-3 to6.5 Ethylene glycol NPr- 68–100 | Twisted tapes with twist ratio 3,4.6 and 6 | In the absence of pressure drop, twist tapes outperformed wirecoil inserts |
Sarma et al. [85] | – | NRe 300–3000 | NPr 3–400 | Twisted tape Twisted ratio of 2.5 | Due to the twisted tape, eddy viscosity becomes more powerful than kinematic viscosity |
Khalil et al. [86] | Water | NRe 690–2195 | NPr 2.9–3.55 | Triangular cut Twist tapes with twist ratio 2.77and width (1.5, 3, 4.5) | The pumping power and overall enhancement ratio are directly proportional to NNu |
Chang et al. [87] | Air | NRe 1000–40,000 | – | Broken twisted tapes insert with twist ratio 1, 1.5, 2, 2.5 or ∞ | This paper looks at heat transfer coefficients, pressure drop factors, and thermal efficiency |
Chang et al. [88] | polytetraf luoroethy lene | NRe 1500–14,000 | – | Single, twin And Triple twisted tapes | When laminar and turbulent flow were present, single and triple twist tape were successful |
Sivashanmugam and Suresh [89] | Water | NRe 2700–13,500 | – | Helical screw- tape insert with increasing and decreasing order | The heat transfer coefficient and friction factor increased with the twist ratio of 1.95, resulting in a high NNu |
Durga prasad and Deepak [90] | Al2O3/ Water Nanofluid | NRe 3000 to30000 | – | Trapezoidal cut(H/D = 5) twisted tape with twist ratio between 5 and 20 | Nano fluids have a higher heat transfer efficiency than water |
Eiamsa-Ard et al. [91] | Water | NRe 3700–21,000 | – | Twin counter twisted tapes and twin co- twisted tapes with twist ratio 2.4,3, 3.5 and 4 | Twin counter-twisted tapes outperform twin co-twisted tapes in terms of performance |