The Flow Calculations in the High Temperature Heat Exchanger With the Manufacturing Geometrical Effects

Computational simulations of a flow in the high temperature offset strip-fin heat exchanger to study the manufacturing geometrical effects (MGE) were conducted. The considered heat exchanger design is used in the cooling cycle in advanced nuclear reactors for hydrogen production by the sulfur iodine thermo-chemical cycle. The study is conducted with helium gas and molten salt as the working fluids with two different channel flow surfaces: fins with roundings on their bases (manufacturing geometrical effects (MGE)) and fins without roundings on their bases. The pre-processor GAMBIT is used to generate a computational mesh, and the CFD software package FLUENT (parallel version), that is based on the finite volume method is used to perform numerical simulations. Because the Reynolds number for the helium side is about 3000, two different models were used for the calculations: laminar model and k-ω turbulence model (for transition flow). The Reynolds number for the molten salt side is less than 100; therefore the laminar flow model was used for these calculations. The results show that manufacturing geometrical effects influence very strongly pressure drop and are negligibly small for temperature and heat transfer.