scholarly journals Turbulent Axisymmetric Non-Isothermal Flow of The Hitec Molten Salt with Temperature Dependent Properties: A Numerical Investigation

2021 ◽  
Vol 86 (2) ◽  
pp. 1-14
Author(s):  
Ahmed I. ElShafei ◽  
Amr Guaily ◽  
Mohammed A. Boraey
Keyword(s):  
Heat Flux ◽  
Reynolds Number ◽  
Surface Heat Flux ◽  
Independent Study ◽  
Surface Heat ◽  
Temperature Dependent ◽  
Hydraulic Behavior ◽  
Wide Range ◽  
Small Change ◽  
Temperature Dependent Properties

This study aims to investigate the Hitec molten salt’s thermal-hydraulic behavior in a smooth round pipe under broad ranges of surface heat flux and Reynolds number (q = 104 – 105 W/m2, Re = 104 – 105). Mesh independent study was performed to ensure the robustness of the model to achieve accurate solutions. Presentation of temperature, pressure and thermophysical properties for multiple cases are presented and discussed. Temperature gradient decreases at high Reynolds number leading to small change in thermo-physical properties. While pressure seems not to be affected by the change in the applied surface heat flux, it increasess linearly across the pipe with the increase in Reynolds number. This analysis aims to provide better understanding of the thermal-hydraulic behavior for fluids with temperature dependent properties for a wide range of Re and surface heat flux.

scholarly journals Experimental Study of Forced- Convection from Horizontal Rectangular Fins Array into Air Duct

2019 ◽  
Vol 15 (1) ◽  
pp. 35-45
Author(s):  
Saad Najeeb Shehab
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Flow Velocity ◽  
Forced Convection ◽  
Surface Heat Flux ◽  
Rectangular Cross Section ◽  
Air Flow ◽  
Surface Heat ◽  
Wide Range ◽  
Air Flow Velocity

    In this work, an experimental study has been done to expect the heat characteristics and performance of the forced-convection from a heated horizontal rectangular fins array to air inside a rectangular cross-section duct. Three several configurations of rectangular fins array have been employed. One configuration without notches and perforations (solid) and two configurations with combination of rectangular-notches and circular-perforations for two various area removal percentages from fins namely 18% notches-9% perforations and 9% notches-18% perforations are utilized.  The rectangular fins dimensions and fins number are kept constant. The fins array is heated electrically from the base plate with five different magnitudes of power-inputs. Five several air flow velocity into a duct are utilized. The influence of fin geometry, air flow velocity, Reynolds number and the surface heat flux on the heat-performance of forced heat convection have been simulated and studied experimentally. The experimental data indicates that the combination of 18% rectangular-notched and 9% circular-perforated rectangular fins array gave best forced heat performance in terms of average heat transfer coefficient about (25% - 45%) and (7% - 20%) compared than solid and 9% notches with18% perforations fins array respectively. Five empirical correlations to predict the average Nusselt number for the 18% notches with 9% perforations rectangular fins array at wide range of surface heat flux are deduced. The present data are compared with previous works and a good closeness in behavior is noticed.

The Measurement of Surface Heat Flux Using the Peltier Effect

1989 ◽  
Vol 111 (3) ◽  
pp. 798-803 ◽  
Author(s):  
E. C. Shewen ◽  
K. G. T. Hollands ◽  
G. D. Raithby
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Physical Models ◽  
Peltier Effect ◽  
Absolute Accuracy ◽  
Measuring Surface ◽  
Wide Range

Calorimetric methods for measuring surface heat flux use Joulean heating to keep the surface isothermal. This limits them to measuring the heat flux of surfaces that are hotter than their surroundings. Presented in this paper is a method whereby reversible Peltier effect heat transfer is used to maintain this isothermality, making it suitable for surfaces that are either hotter or colder than the surroundings. The paper outlines the theory for the method and describes physical models that have been constructed, calibrated, and tested. The tested physical models were found capable of measuring heat fluxes with an absolute accuracy of 1 percent over a wide range of temperature (5–50°C) and heat flux (15–500 W/m2), while maintaining isothermality to within 0.03 K. A drawback of the method is that it appears to be suited only for measuring the heat flux from thick metallic plates.

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