Some Remarks on the Helical-Cartesian Coordinate System and Its Applications

Xu, Zhong-Guang; Fan, Dah‐Nien

doi:10.1115/1.3242607

Cited by 2 publications

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“…Similar expected enhancement was not observed for higher twist ratios (5-20) studied by author. Later Xu & Fan (1986) suggested correction in the viscous dissipation term used by Masilyah & Nandakumar (1981a, b). Chang et al (1988) used numerical method to study laminar flow in a twisted elliptic tube for large twist ratios (H = 21, 53, 106).…”

Section: Introductionmentioning

confidence: 99%

Laminar flow heat transfer studies in a twisted square duct for constant wall heat flux boundary condition

Bhadouriya

Agrawal

Prabhu

2015

Sadhana

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The problem of fluid flow and heat transfer was studied for flow inside twisted duct of square cross-section. Three-dimensional numerical solutions were obtained for steady fully developed laminar flow and for uniform wall heat flux boundary conditions using commercially available software. Reynolds number range considered was 100-3000. Twist ratio used are 2.5, 5, 10 and 20. Fluids considered are in Prandtl number range of 0.7-20. Product of friction factor and Reynolds number is found to be a function of Reynolds number and maximum values are observed for a twist ratio of 2.5 and Reynolds number of 3000. Maximum Nusselt number is observed for the same values along with Prandtl number of 20. Correlations for friction factor and Nusselt number are developed involving swirl parameter. Local distribution of friction factor ratio and Nusselt number across a cross-section is presented. Based on constant pumping power criteria, enhancement factor is defined to compare twisted ducts with straight ducts. Selection of twisted square duct is presented in terms of enhancement factor. It is found that twisted duct performs well in the laminar region for range of parameters studied. Heat transfer enhancement for Reynolds number of 3000 and Prandtl number of 0.7 for twist ratio of 2.5, 5, 10, and 20 is 20%, 17.8%, 16.1% and 13.7%, respectively. The results are significant because it will contribute to development of energy efficient compact size heat exchangers.

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Section: Introductionmentioning

confidence: 99%

Laminar flow heat transfer studies in a twisted square duct for constant wall heat flux boundary condition

Bhadouriya

Agrawal

Prabhu

2015

Sadhana

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Experimental and Numerical Study of Turbulent Heat Transfer in Twisted Square Ducts

Wang

Tao

Wang

et al. 2001

Journal of Heat Transfer

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This paper describes the experimental and numerical study of three mildly twisted square ducts (twisted uniform cross section square duct, twisted divergent square duct and twisted convergent square duct). Experiments are conducted for air with uniform heat flux condition. Measurements are also conducted for a straight untwisted square duct for comparison purpose. Numerical simulations are performed for three-dimensional and fully elliptic flow and heat transfer by using a body-fitted finite volume method and standard k−ε turbulence model. Both experimental and numerical results show that the twisting brings about a special variation pattern of the spanwise distribution of the local heat transfer coefficient, while the divergent and convergent shapes lead to different axial local heat transfer distributions. Based on the test data, the thermal performance comparisons are made under three constraints (identical mass flow rate, identical pumping power and identical pressure drop) with straight untwisted square duct as a reference. Comparisons show that the twisted divergent duct can always enhance heat transfer, the twisted convergent duct always deteriorates heat transfer, and the twisted constant cross section duct is somewhat in between.

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Some Remarks on the Helical-Cartesian Coordinate System and Its Applications

Cited by 2 publications

References 0 publications

Laminar flow heat transfer studies in a twisted square duct for constant wall heat flux boundary condition

Laminar flow heat transfer studies in a twisted square duct for constant wall heat flux boundary condition

Experimental and Numerical Study of Turbulent Heat Transfer in Twisted Square Ducts

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