Numerical simulation of conjugate heat transfer in a tube bank of a subsea cooler based on buoyancy effects

Abstract

The contribution deals with a model of passive heat exchanger based on the buoyancy effects aimed at subsea processing of natural gas produced. 3D unsteady external buoyancy-induced seawater flow through a staggered tube bundle at Gr = 3 x 105 was simulated using the full Navier-Stokes equations with no turbulence model in combination with the unsteady RANS modelling of internal natural gas flow at Re = 8x105 and simulation of heat conduction through the steel pipe wall. Evolution of internal and external flow and temperature fields as well as variations in the heat output from row to row are predicted. It was found that the conjugate problem formulation resulted in dramatic changes in draft flow characteristics and external heat transfer coefficient values as compared with the simplified formulation based on the isothermal pipe wall assumption.