Effect of Apex Angle on the Flow and Heat Transfer in Triangular Porous Ducts With Iso-Flux Boundary Conditions

2011 ◽  
Author(s):  
S. Negin Mortazavi ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Boundary Conditions ◽  
Integral Method ◽  
Apex Angle ◽  
Triangular Channel ◽  
Flow And Heat Transfer ◽  
Temperature Distributions ◽  
Flux Boundary Conditions

This study presents an analysis of fully developed laminar flow in a porous triangular channel. The flow is assumed to have constant properties and the porous channel is an isotropic matrix. Very accurate analytical solutions are presented by Galerkin Integral method for iso-flux boundary conditions. In this paper, the effect of apex angle in the triangular channel is shown on the velocity and temperature distributions along with the friction factor fRe, and the Nusselt number NuH.

A Heat Transfer in Iso-Thermal Triangular Channel Filled With Porous Media

2012 ◽  
Author(s):  
S. Negin Mortazavi ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Nusselt Number ◽  
Temperature Distribution ◽  
Boundary Conditions ◽  
Forced Convection ◽  
Constant Temperature ◽  
Analytical Solutions ◽  
Apex Angle ◽  
Triangular Channel

This study presents an analysis of forced convection in a porous triangular channel. The flow is laminar, fully developed and assumed to have constant properties. The porous channel has an isotropic matrix and the boundary conditions are fixed with a constant temperature. In this paper, accurate analytical solutions are presented to determine the effects of apex angle and porous media properties on the temperature distribution in a triangular channel along with the Nusselt number NuT.

Effect of Porous Media Properties on Heat Transfer in Triangular Porous Duct

2012 ◽  
Author(s):  
S. Negin Mortazavi ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Nusselt Number ◽  
Temperature Distribution ◽  
Boundary Conditions ◽  
Analytical Solutions ◽  
Series Solution ◽  
Apex Angle ◽  
Average Temperature ◽  
Triangular Channel

This study presents an analysis of forced convection in a porous triangular channel. The flow is laminar, fully developed and assumed to have constant properties. The porous channel has an isotropic matrix and the boundary conditions are fixed with constant temperature. In this paper, accurate analytical solutions are presented to determine the effects of apex angle and porous media properties on the velocity and temperature distribution in a triangular channel along with the friction factor fRe, and Nusselt number NuT. The presentaion includes numerical features of the exact series solution using Brinkman’s model. Numerical results for dimensionless average temperature and velocity are presented for various porosities, permeabilities and apex angles.

scholarly journals Experimental Study on Liquid Flow and Heat Transfer in Rough Microchannels

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Xuan Zhang ◽  
Taocheng Zhao ◽  
Suchen Wu ◽  
Feng Yao
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Cross Section ◽  
Liquid Flow ◽  
Flow And Heat Transfer ◽  
Section Shape ◽  
Poiseuille Number

Although roughness is negligible for laminar flow through tubes in classic fluid mechanics, the surface roughness may play an important role in microscale fluid flow due to the large ratio of surface area to volume. To further verify the influence of rough surfaces on microscale liquid flow and heat transfer, a performance test system of heat transfer and liquid flow was designed and built, and a series of experimental examinations are conducted, in which the microchannel material is stainless steel and the working medium is methanol. The results indicate that the surface roughness plays a significant role in the process of laminar flow and heat transfer in microchannels. In microchannels with roughness characteristics, the Poiseuille number of liquid laminar flow relies not only on the cross section shape of the rough microchannels but also on the Reynolds number of liquid flow. The Poiseuille number of liquid laminar flow in rough microchannels increases with increasing Reynolds number. In addition, the Nusselt number of liquid laminar heat transfer is related not only to the cross section shape of a rough microchannel but also to the Reynolds number of liquid flow, and the Nusselt number increases with increasing Reynolds number.

Flow and Heat Transfer in Ducts of Arbitrary Shape With Arbitrary Thermal Boundary Conditions

1966 ◽  
Vol 88 (4) ◽  
pp. 351-357 ◽  
Author(s):  
E. M. Sparrow ◽  
A. Haji-Sheikh
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Cross Section ◽  
Arbitrary Cross Section ◽  
Space Technology ◽  
Closed Form Solutions ◽  
Thermal Boundary Conditions ◽  
Flow And Heat Transfer ◽  
Temperature Distributions ◽  
Circular Segment

A computation-oriented method of analysis is presented for determining closed-form solutions for fully developed laminar flow and heat transfer in ducts of arbitrary cross section. The analytical method can accommodate both uniform and circumferentially varying thermal boundary conditions. The solutions provide information for local quantities such as the velocity and the temperature distributions as well as for overall quantities such as the friction factor and the Nusselt number. As an application of the method, solutions are presented for flow and for heat transfer in ducts of circular-segment cross section, a configuration that is of current interest in space technology.

Heat Transfer in Pipe Flow

2008 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Temperature Distribution ◽  
Laminar Flow ◽  
Pipe Flow ◽  
Simple Procedure ◽  
Internal Flow ◽  
Uniform Heat Flux ◽  
Flux Boundary Conditions

A simple procedure using spreadsheets is presented where the temperature distribution for laminar flow in a circular pipe is determined from the entrance of the pipe up to the fully developed region is calculated numerically. The results are then used to show the different features of internal flow like constancy of Nusselt number. The solution is presented for both isothermal and uniform heat flux boundary conditions and are then compared with available correlations.

Laminar Flow Forced Convection Heat Transfer Behavior of a Phase Change Material Fluid in Microchannels

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Satyanarayana Kondle ◽  
Jorge L. Alvarado ◽  
Charles Marsh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Boundary Conditions ◽  
Phase Change ◽  
Effective Specific Heat ◽  
Transfer Behavior ◽  
Peripheral Temperature ◽  
Change Material

In this paper, a phase change material (PCM) fluid (N-eicosane) is compared with pure water as heat transfer fluid. The heat transfer behavior of PCM fluid under laminar flow conditions (Reynolds number of 700) in circular and rectangular microchannels was studied numerically. In the numerical study, an effective specific heat model was used to take into account the phase change process. Heat transfer results for circular and rectangular microchannels with PCM fluid were obtained under hydrodynamically and thermally fully developed conditions. A PCM fluid in microchannels with aspect ratios of 1 to 2, 1 to 4, and 1 to 8 was found to enhance the thermal behavior of microchannels which can be beneficial in a host of cooling applications. The flow was assumed to be hydrodynamically fully developed at the inlet and thermally developing inside the microchannel. Heat transfer characteristics of PCM slurry flow in microchannels have been studied under three types of wall boundary conditions including constant axial heat flux with constant peripheral temperature (H1), constant heat flux with variable peripheral temperature (H2), and constant wall temperature (T) boundary condition. The fully developed Nusselt number was found to be higher for H1 than for H2 and T boundary conditions for all the geometries. Moreover, Nusselt number also increased with aspect ratio and was sensitive to the variations in effective specific heat.

scholarly journals Uncertainties Analysis on the Prediction of Flow and Heat Transfer of Liquid Sodium with CFD Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhanwei Liu ◽  
Xinyu Li ◽  
Tenglong Cong ◽  
Rui Zhang ◽  
Lingyun Zheng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Coefficient ◽  
Liquid Sodium ◽  
Heat Transfer Characteristics ◽  
Backward Facing Step ◽  
Heating Wall ◽  
Transfer Characteristics ◽  
Cfd Models ◽  
Flow And Heat Transfer

The prediction of flow and heat transfer characteristics of liquid sodium with CFD technology is of significant importance for the design and safety analysis of sodium-cooled fast reactor. The accuracies and uncertainties of the CFD models should be evaluated to improve the confidence of the numerical results. In this work, the uncertainties from the turbulent model, boundary conditions, and physical properties for the flow and heat transfer of liquid sodium were evaluated against the experimental data. The results of uncertainty quantization show that the maximum uncertainties of the Nusselt number and friction coefficient occurred in the transition zone from the inlet to the fully developed region in the circular tube, while they occurred near the reattachment point in the backward-facing step. Furthermore, in backward-facing step flow, the maximum uncertainty of temperature migrated from the heating wall to the geometric center of the channel, while the maximum uncertainty of velocity occurred near the vortex zone. The results of sensitivity analysis illustrate that the Nusselt number was negatively correlated with the thermal conductivity and turbulent Prandtl number, while the friction coefficient was positively correlated with the density and Von Karman constant. This work can be a reference to evaluate the accuracy of the standard k-ε model in predicting the flow and heat transfer characteristics of liquid sodium.

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