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Thermal Analysis of Convection and Radiation in Finned Heat Exchanger By
Qusay R. Al-Hagag
ABSTRACT:
The object of this study is to analyze the heat exchanging fins and to show the effects of convection and radiation in heat transfer model on a catalytic reactor. Reactant gas enters the catalytic reactor path and heat transfer in the stainless steel profile is studied. Due to symmetry, one of the walls may used. The temperature of reactor surface and the temperature profile of fin can be estimated by simulation using ANSYS. The temperature profiles of radiation show different aspects. The radiation term did not affect the temperature profile for this reason the radiation can be ignored in the forced convection system. On the other hand, the calculation of natural convection shows similar result to ANSYS result. However, in forced convection, the manual calculation is lower than that of ANSYS. Even though the temperature profile of forced convection has differences between ANSYS and manual calculations, the temperatures at the end of the fin are same. From above, the radiation term is important in natural convection system.
For the effect of material properties, the material is changed from steel AISI 4340 to aluminum. The temperature at the surface of the aluminum wall is 150K higher than that of steel.
Heat exchangers are
commonly used in many fields of industry, which are composed of finned surfaces
for dissipation of heat by convection and conduction. The calculation of heat
transfer of a cooling fin in heat exchanger system is the good practical
application of heat transfer. Such fins are used to increase the cooling area
of system available for heat transfer between metal walls and conducting fluid
such as gases and liquds[1]. In a chemical process, the reactor at hot
temperature is cooled using cooling fins. The coolant is the surrounding air.
Heat transfer in heat exchanger is dominated by convection from the surfaces,
although the conduction within the fin may also influence on the performance. A
convenient method to treat convection cooling is to use heat transfer
coefficients, h[2].
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- Thermal Analysis of Convection and Radiation in Finned Heat Exchanger
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