Thermal stress analysis of a Water-Molten Salt Heat Exchanger: Computational Fluid Dynamics with Fluid-Structure Interaction
Translated title
Thermal stress analysis of a Water-Molten Salt Heat Exchanger
Author
Naider, Jakub
Term
4. semester
Education
Publication year
2023
Submitted on
2023-05-31
Pages
71
Abstract
A CFD analysis has been performed for the simulation of a molten sodium hydroxide heat exchanger. Two different designs were investigated: Double pipe and U-tube heat exchangers for 3 different pressures (1,2 and 5 [bar]) of the working fluid, which was water. Then the FEM analysis of Thermal stress was performed. The simulations ran with the assumption that stress induced by constrained expansion is covered by the heat exchanger design apart from one for the atmospheric pressure for the U-tube heat exchanger. In this simulation, it was assumed that the baffle is pressed on the heat exchanger tubes and any expansion of the tubes is constrained by the baffle. Additionally, the Factor of Safety for each simulation was computed in order to find out, if the stress exceeds the tensile yield strength and thus the elastic range. The comparison between each of the scenarios revealed that considering the same properties and boundary conditions Double pipe HX produces higher amounts of thermal stress, but still keeps the levels of Factor of Safety at an acceptable level. Moreover, it has been found that it is necessary to apply safety measures to the expansion of the pipes as the Factor of Safety for a case with constrained expansion was less than 1 and thus elastic range was exceeded and the pipes are irreversibly damaged
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