Effect of fluid thermal properties on the heat transfer characteristics in a double-pipe helical heat exchanger

Rennie, Timothy J.; Raghavan, Vijaya

doi:10.1016/j.ijthermalsci.2006.02.004

Cited by 25 publications

(11 citation statements)

References 19 publications

(28 reference statements)

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“…In various numerical studies reported (Rennie and Raghavan, 2006a,b;Kumar et al, 2006) on heat transfer in a double pipe heat exchanger, constant properties of the heating/cooling medium were considered. In a later work by Rennie and Raghavan (2006b), the effect of change of Prandtl number on heat transfer was studied. Two studies were performed by them; in the first one, they have considered three Prandtl numbers obtained by changing the thermal conductivity of the fluid.…”

Section: Effect Of Property Values On Cfd Modelling Of Heat Transfer mentioning

confidence: 99%

“…In the present analysis, we consider the transport and thermal properties of the heat exchange medium (both hot and cold fluids) to be dependent on the temperature; rather than studying the influence of Pr alone as reported by Rennie and Raghavan (2006b). The plots of density, viscosity, thermal conductivity and specific heat of water are given in Fig.…”

Section: Effect Of Property Values On Cfd Modelling Of Heat Transfer mentioning

confidence: 99%

See 1 more Smart Citation

Experimental and CFD estimation of heat transfer in helically coiled heat exchangers

Jayakumar

Mahajani

Mandal

et al. 2008

Chemical Engineering Research and Design

371

115

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Section: Effect Of Property Values On Cfd Modelling Of Heat Transfer mentioning

confidence: 99%

Section: Effect Of Property Values On Cfd Modelling Of Heat Transfer mentioning

confidence: 99%

Experimental and CFD estimation of heat transfer in helically coiled heat exchangers

Jayakumar

Mahajani

Mandal

et al. 2008

Chemical Engineering Research and Design

371

115

View full text Add to dashboard Cite

“…Therefore, it is important to research and understand the effects of the properties, and how the flow rates and geometry can affect the heat transfer characteristics in industrial application [21] The variation in temperature along the flowpath affects their properties and causes changes in the convective heat transfer coefficient. Density, viscosity, thermal conductivity, and specific heat are temperature-sensitive properties [25].…”

Section: Boundary Conditionsmentioning

confidence: 99%

Comparison and validation of turbulence models in the numerical study of heat exchangers

2015

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This study aims to validate numerical models for heat exchangers developed with the commercial package ANSYS®, comparing the results with data published in the literature. The methodology was based on the identification of programs, languages, mathematical models, and numerical models used by other researchers. Geometries were developed with SolidEdge® and DesignModeler®, discretization meshes with Meshing®, and subsequent configuration of standard k-ɛ and k-ω models with Fluent® and CFX®. For internal flow in concentric smooth straight tube exchangers, we recreated the predicted results with Nusselts varying between 100 and 250 and Reynolds regimes between 12*10 3 and 38*10 3 . The study of internal flow in the curved corrugated tube exhibited considerable approximation to the results predicted by Zachar's numerical correlation with Nusselt numbers in the range of 15-70 for Dean variations between 1*10 2 and 11*10 2 in laminar flow. Likewise, we validated the study of external flow in twisted curved tubes. Finally, Nusselt variations between 60 and 275 for Dean variations between 1*10 3 and 9*10 3 were modeled for completely developed laminar, transitional, and turbulent flow. The study shows the increase of heat flux associated with the change in the geometry of heat exchangers. It also demonstrates how numerical computer models can recreate realistic process conditions and thermo-fluid simulation by appropriately configuring systems.

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“…(r, θ, z) are the cylindrical coordinate system and v r , v θ , v z are the corresponding velocity components. Neglecting viscous dissipation and axial conduction, the governing equations for a steady, incompressible, fully developed laminar flow can be written in the cylindrical coordinate system as (Rennie and Raghavan, 2006). …”

Section: Introductionmentioning

confidence: 99%

Effects of temperature-dependent viscosity on fluid flow and heat transfer in a helical rectangular duct with a finite pitch

Wang

Liu

et al. 2014

Braz. J. Chem. Eng.

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-An incompressible fully developed laminar flow in a helical rectangular duct having finite pitch and curvature with temperature-dependent viscosity under heating condition is studied in this work. Both the cases of one wall heated and four walls heated are studied. The cross-sectional dimensions of the rectangular duct are 2a and 2b. The aspect ratio η= 2b 2a is 0.5. Water is used as the fluid and Reynolds number (Re) is varied in the range of 100 to 400. The secondary flow with temperature-dependent viscosity is enhanced markedly as compared to constant viscosity. An additional pair of vortices is obtained near the center of the outer wall at Re=400 for the model of four walls heated with temperature-dependent viscosity, y, while for constant viscosity, the appearance of two additional vortices near the outer wall cannot be found. Besides, the axial velocity decreases and the temperature increases at the central region of the rectangular duct when the temperature-dependent viscosity is considered. Due to the decrease of the viscosity near the walls, the friction factor obtained with temperature-dependent viscosity is lower than that of constant viscosity, while the convective heat transfer for temperature-dependent viscosity is significantly enhanced owing to the strengthened secondary flow. Especially for four heated walls, the effects of viscosity variation on the flow resistance and heat transfer are more significant.

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Effect of fluid thermal properties on the heat transfer characteristics in a double-pipe helical heat exchanger

Cited by 25 publications

References 19 publications

Experimental and CFD estimation of heat transfer in helically coiled heat exchangers

Experimental and CFD estimation of heat transfer in helically coiled heat exchangers

Comparison and validation of turbulence models in the numerical study of heat exchangers

Effects of temperature-dependent viscosity on fluid flow and heat transfer in a helical rectangular duct with a finite pitch

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