Numerical computations on flow and heat transfer characteristics of a helically coiled heat exchanger using different turbulence models

This study investigates the thermal-hydraulic characteristics of helically coiled tube heat exchangers applied in high temperature gas reactors. In the heat exchanger, the high-temperature helium and the low-temperature water flow through the shell side and the coiled tube, respectively. Three turbulence models are incorporated with Navier-Stokes equations in the numerical simulations: realizable k-ɛ, low-Reynolds k-ɛ and Reynolds stress. Existing experimental data on the Nusselt (Nu) number validate the present CFD simulations using these turbulence models.