Experimental study of agitator geometry and speed on heat transfer coefficients for both Newtonian and time dependent Power law fluids

2020 ◽  
Vol 56 (12) ◽  
pp. 3167-3175
Author(s):  
S. K. Ansar Ali
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Power Law ◽  
Time Dependent ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Power Law Fluids

scholarly journals Fluid Flow and Heat Transfer in Power-Law Fluids Across Circular Cylinders: Analytical Study

2005 ◽  
Author(s):  
Waqar A. Khan ◽  
Richard J. Culham ◽  
Milan M. Yovanovich
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Integral Equation ◽  
Power Law ◽  
Circular Cylinders ◽  
Integral Approach ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Power Law Fluids ◽  
Power Law Index

An integral approach of the boundary layer analysis is employed for the modeling of fluid flow around and heat transfer from infinite circular cylinders in power-law fluids. The Von Karman-Pohlhausenmethod is used to solve the momentum integral equation whereas the energy integral equation is solved for both isothermal and isoflux boundary conditions. A fourth-order velocity profile in the hydrodynamic boundary layer and a third-order temperature profile in the thermal boundary layer are used to solve both integral equations. Closed form expressions are obtained for the drag and heat transfer coefficients that can be used for a wide range of the power-law index, and generalized Reynolds and Prandtl numbers. It is found that pseudoplastic fluids offer less skin friction and higher heat transfer coefficients than dilatant fluids. As a result, the drag coefficients decrease and the heat transfer increases with the decrease in power-law index. Comparison of the analytical models with available experimental/numerical data proves the applicability of the integral approach for power-law fluids.

scholarly journals Fluid Flow and Heat Transfer in Power-Law Fluids Across Circular Cylinders: Analytical Study

2006 ◽  
Vol 128 (9) ◽  
pp. 870-878 ◽  
Author(s):  
W. A. Khan ◽  
J. R. Culham ◽  
M. M. Yovanovich
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Integral Equation ◽  
Power Law ◽  
Circular Cylinders ◽  
Integral Approach ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Power Law Fluids ◽  
Power Law Index

An integral approach of the boundary layer analysis is employed for the modeling of fluid flow around and heat transfer from infinite circular cylinders in power-law fluids. The Von Karman-Pohlhausen method is used to solve the momentum integral equation whereas the energy integral equation is solved for both isothermal and isoflux boundary conditions. A fourth-order velocity profile in the hydrodynamic boundary layer and a third-order temperature profile in the thermal boundary layer are used to solve both integral equations. Closed form expressions are obtained for the drag and heat transfer coefficients that can be used for a wide range of the power-law index, and generalized Reynolds and Prandtl numbers. It is found that pseudoplastic fluids offer less skin friction and higher heat transfer coefficients than dilatant fluids. As a result, the drag coefficients decrease and the heat transfer increases with the decrease in power-law index. Comparison of the analytical models with available experimental/numerical data proves the applicability of the integral approach for power-law fluids.

An Experimental Study of Free Corrective Heat Transfer in a Parallelogrammic Enclosure

1983 ◽  
Vol 105 (3) ◽  
pp. 433-439 ◽  
Author(s):  
N. Seki ◽  
S. Fukusako ◽  
A. Yamaguchi
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Nusselt Number ◽  
Correlation Equation ◽  
Transformer Oil ◽  
Experimental Measurements ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Prandtl Numbers ◽  
Rayleigh Numbers

Experimental measurements are presented for free convective heat transfer across a parallelogrammic enclosure with the various tilt angles of parallel upper and lower walls insulated. The experiments covered a range of Rayleigh numbers between 3.4 × 104 and 8.6 × 107, and Prandtl numbers between 0.70 and 480. Those also covered the tilt angles of the parallel insulated walls with respect to the horizontal, φ, of 0, ±25, ±45, ±60, and ±70 deg under an aspect ratio of H/W = 1.44. The fluids used were air, transformer oil, and water. It was found that the heat transfer coefficients for φ = −70 deg were decreased to be about 1/18 times those for φ = 0 deg. Experimental results are given as plots of the Nusselt number versus the Rayleigh number. A correlation equation is given for the Nusselt number, Nu, as a function of φ, Pr, and Ra.

scholarly journals Heat Transfer Boundary Conditions in the RELAP5-3D Code

2008 ◽  
Author(s):  
Richard A. Riemke ◽  
Cliff B. Davis ◽  
Richard R. Schultz
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Surface Temperature ◽  
Volume Fraction ◽  
Control Variable ◽  
Time Dependent ◽  
Fluid Temperature ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
General Table

The heat transfer boundary conditions used in the RELAP5-3D computer program have evolved over the years. Currently, RELAP5-3D has the following options for the heat transfer boundary conditions: (a) heat transfer correlation package option, (b) non-convective option (from radiation/conduction enclosure model or symmetry/insulated conditions), and (c) other options (setting the surface temperature to a volume fraction averaged fluid temperature of the boundary volume, obtaining the surface temperature from a control variable, obtaining the surface temperature from a time-dependent general table, obtaining the heat flux from a time-dependent general table, or obtaining heat transfer coefficients from either a time- or temperature-dependent general table). These options will be discussed, including the more recent ones.

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