Influence of system buoyancy and hydraulic diameter on turbulent mixed convection in a rectangular duct

2021 ◽  
Vol 176 ◽  
pp. 121411
Author(s):  
Myeong-Seon Chae ◽  
Bum-Jin Chung
Keyword(s):  
Mixed Convection ◽  
Hydraulic Diameter ◽  
Rectangular Duct

scholarly journals MHD Mixed Convection Micropolar Fluid Flow through a Rectangular Duct

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mekonnen Shiferaw Ayano ◽  
Stephen T. Sikwila ◽  
Stanford Shateyi
Keyword(s):  
Magnetic Field ◽  
Differential Equations ◽  
Mixed Convection ◽  
Applied Magnetic Field ◽  
Flow Reversal ◽  
Convection Flow ◽  
Temperature Profiles ◽  
Rectangular Duct ◽  
Micropolar Fluid Flow ◽  
Flow Through

Mixed convection flow through a rectangular duct with at least one of the sides of the walls of the rectangle being isothermal under the influence of transversely applied magnetic field has been analyzed numerically in this study. The governing differential equations of the problem have been transformed into a system of nondimensional differential equations and then solved numerically. The dimensionless velocity, microrotation components, and temperature profiles are displayed graphically showing the effects of various values of the parameters present in the problem. The results showed that the flow field is notably influenced by the considered parameters. It is found that increasing the aspect ratio increases flow reversal, commencement of the flow reversal is observed after some critical value, and the applied magnetic field increases the flow reversal in addition to flow retardation. The microrotation components flow in opposite direction; also it is found that one component of the microrotation will show no rotational effect around the center of the duct.

Heat Transfer Characteristics of a Non-Rotating Two-Pass Rectangular Duct With Various Guide Vanes in the Tip Turn Region

2011 ◽  
Author(s):  
Dong Myeong Lee ◽  
Jun Su Park ◽  
Dong Hyun Lee ◽  
Beom Soo Kim ◽  
Hyung Hee Cho
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Hydraulic Diameter ◽  
Rectangular Duct ◽  
Transfer Coefficients ◽  
Enhanced Heat Transfer ◽  
Guide Vanes ◽  
High Heat Transfer ◽  
Naphthalene Sublimation Technique ◽  
Blade Tip

The present study investigated convective heat transfer inside a two-pass rectangular duct with guide vanes in the turning region. The objective was to determine the effect of the guide vanes on blade tip cooling. The duct had a hydraulic diameter (Dh) of 26.67 mm and an aspect ratio (AR) of 5. The duct inlet width was 80 mm, and the distance between the tip of the divider and the tip wall of the duct was also 80 mm. Various guide vane configurations were used in the turning region. The Reynolds number (Re), based on the hydraulic diameter, was held constant at 10,000. The naphthalene sublimation technique was used to determine the detailed local heat transfer coefficients, using the heat and mass transfer analogy. The results indicated that guide vanes in the turning region enhanced heat transfer in the blade tip region. The guide vane on the second-pass side of the turning region had higher heat transfer than the guide vane on the first-pass side. Strong secondary flow enhanced heat transfer in the blade tip region. Dean vortices induced by the guide vanes pushed the high-momentum core flow towards the tip wall, and heat transfer was increased in the turning region, but decreased in the second passage. Consequently, a guide vane on the second-pass side of the turning region generates high heat transfer rates on the tip surface, and can also increase the thermal performance factor in a two-pass duct.

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