A numerical study on heat transfer and friction factor characteristics of laminar flow in a circular tube fitted with center-cleared twisted tape

Guo, Jian; Fan, Aiwu; Zhang, Xiaoyu; Liu, Wei

doi:10.1016/j.ijthermalsci.2011.02.010

Cited by 255 publications

(62 citation statements)

References 24 publications

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“…4. An axial location of 0.866m is considered because this location is near the exit of the domains, and in an induced domain the flow across its cross-sections which have the same type of cut are the same as the flow is approaching the end of the domain [23].…”

Section: Flow Field 81mentioning

confidence: 99%

“…Through the numerical study carried out by Guo et al [23], they observed that centre-cleared twisted tape is a promising technique for heat transfer enhancement. Their results revealed that the thermal performance of a tube with centre-cleared twisted tape has an improvement over that of a plain tube, and that the thermal performance of the tube with centre-cleared twisted tape can be enhanced by 7% -20% compared with those with plain twisted tape.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

Oni

Paul

2016

Applied Thermal Engineering

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An investigation was carried out to analyse numerically heat transfer and flow characteristics of water through a circular tube induced with different twisted tapes. The aim is to know which of the tube designs gives the best performance when compared with a plain tube. Turbulent flow was considered, the walls of the tubes were under uniform wall heat flux, Reynolds number was between 5000 and 20000, and RNG κ-ε model was selected for the simulations. The shape of cuts on the tapes has effects on the performance of the induced tubes. The tube fitted with alternate-axis triangular cut twisted tape has the best performance as its Nusselt number and friction factor are 1.63 -2.18 and 2.60 -3.15 times respectively that of the tube fitted with plain twisted tape while its thermal performance factor is 1.35 -1.43 times that of the tube with plain twisted tape. New correlations were developed for the Nusselt number and friction factors, and reveal that the Nusselt number obtained from the new correlation agrees well with the correlation proposed by Thianpong et al. with a discrepancy of 2.21%. For the friction factor, the discrepancy is 3.01%.

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Section: Flow Field 81mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

Oni

Paul

2016

Applied Thermal Engineering

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“…When all diffusors were compared, Nusselt numbers are also increasing with increasing Reynolds number. This is because of the formation of turbulence in the tube and the resulting increase in the number of Nu (Guo, Fan, Zhang and Liu, 2011). In Fig.…”

Section: Flow In Tubes Having Diffusorsmentioning

confidence: 93%

Experimental InvestigationOf The Effect Of Turbulators On Heat Transfer In Horizontal Tubes

Karagöz¹,

Abdi²,

Ömeroğlu³

2017

AKU-J. Sci. Eng.

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The interest in increasing heat transfer is growing in line with industrial development. In relation to the cooling and heating systems, in particular in industrial-type boilers, the heating boilers and heat exchangers, the use of inserts to enhance heat transfer is quite common. During the design of the heat exchanger while increasing heat transfer, the friction hence the pressure loss will increase as well. As a matter of course, the cost of increased energy consumption for pumping fluid in tubes should be compensated with the reduction in cost of the device. In this experimental study, turbulence creating flaps have been placed into the tubes and compared to the empty tube. Experiments have been carried out using three springs and three twisted tapes having different pitches, and five different Reynolds numbers. The effects on the friction factor and on the number of Nusselt were investigated. Yatay Borulardaki Isı Transferine Türbülatörlerin Etkilerinin Deneysel Olarak Incelenmesi AnahtarkelimelerTürbülatör; Isı transferi; Basınçdüşümü; Yatayboru ÖzetIsı transferini artırmaya olan ilgi endüstriyel gelişme doğrultusunda artmaktadır. Soğutma ve ısıtma sistemleri ile ilişkili, özellikle endüstriyel tip kazanlar, ısıtma kazanları ve ısı eşanjörlerinde, ısı transferini artırmak için türbülatörlerin kullanımı oldukça yaygındır. Eşanjör tasarımında ısı transferini arttırırken , sürtünme dolayısıyla basınç kaybı da artar. Doğal olarak, borulardaki sıvıyı pompalamak için artan enerji tüketiminin maliyeti, cihazın maliyetindeki düşüş ile telafi edilmelidir. Bu deneysel çalışmada türbülans oluşturan kanatlar, tüplere yerleştirildi ve boş tüp ile karşılaştırıldı. Deneyler, farklı aralıklara sahip üç yay ve üç bükülmüş levha ile beş farklı Reynold sayısını kullanarak gerçekleştirildi. Sürtünme faktörü ve Nusselt sayısına etkileri araştırıldı.. © AfyonKocatepeÜniversitesi

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“…The energy equation and k-ε model (second order equation) with enhanced wall treatment were used for modeling the turbulent flow in the analysis. The turbulence model is explained in [16][17][18] and summarized in Table 2 without further explanation. Boundary conditions and material properties were specified as derived from Kini, et al [7][8][9][10][11][12][13][14].…”

Section: Numerical Model and Boundary Conditionsmentioning

confidence: 99%

Effect of V-shaped Ribs on Internal Cooling of Gas Turbine Blades

Kamat

Shenoy

Kini

2017

J. Eng. Technol. Sci.

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Abstract. Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet tem[1perature. The rotor inlet temperatures in most gas turbines are far higher than the melting point of the blade material. Hence the turbine blades need to be cooled. In this work, simulations were carried out with the leading edge of gas turbine blade being internally cooled by coolant passages with V-shaped ribs at angles of 30°, 45° or 60° and at three aspect ratios (1:1, 1:2 and 2:3). The trailing edge of the blade was cooled by cylindrical and triangular pin-fin perforations in staggered and inline arrangements. Numerical analyses were carried out for each configuration of the cooling passages. The best cooling passages for leading edge and trailing edge were deduced by comparing the results of these analyses. It was found that using V-shaped ribs and fins induces a swirling flow, which in turn increases the velocity gradient and hence produces an improvement in heat transfer. The results show that under real time flow conditions, the application of V-shaped ribs and pin-fin perforations is a very promising technique for improving blade life.

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A numerical study on heat transfer and friction factor characteristics of laminar flow in a circular tube fitted with center-cleared twisted tape

Cited by 255 publications

References 24 publications

Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

Experimental InvestigationOf The Effect Of Turbulators On Heat Transfer In Horizontal Tubes

Effect of V-shaped Ribs on Internal Cooling of Gas Turbine Blades

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