A CFD-based simulation of fluid flow and heat transfer in the Intermediate Heat Exchanger of sodium-cooled fast reactor

A three-dimensional computational fluid dynamics (CFD)-based simulation for the Intermediate Heat Exchanger (IHX) of a pool-type sodium-cooled fast neutron reactor has been performed in this paper, which investigates the flow-field and temperature distributions of liquid sodium on both primary and secondary sides at full power conditions. Typically, some simplifications are applied to reduce the difficulty of computation and render the problem more tractable. A proposed method is that treat a number of tubes as porous media that replicates the pressure loss and heat transfer characteristics of the detailed model. The heat exchanger model of the ANSYS FLUENT code is used to analyze the heat transfer phenomena inside of the IHX and the resistance coefficients of porous media have been predicted by empirical relationships which vary with height and flow directions. Two separate models, with different size of inlet and outlet area for shell-side sodium, have been developed in this paper. By comparing the results from the different simulations, the model with larger inlet area for primary and non-uniform inlet velocity distribution of secondary sodium satisfies the design requirements with respect to the permissible upper limit of temperature difference and local radial velocity.