Intensification of Heat Transfer in Heat Exchangers with Diffuser Channels

The results of studies on the intensification of heat transfer in round and flat continuous diffusers for a number of diffusers’ opening angles are presented. Numerical modeling of heat transfer is carried out using a three-parameter differential RANS turbulence model supplemented with a transfer equation for a turbulent heat flow. It is shown that at the same opening angle in a round diffuser, the friction coefficient, Nusselt number, and turbulence intensity are significantly higher than in a flat diffuser, and these excesses increase with an increase in the opening angle. The possibility of using diffuser channels in plate and round pipe-in-pipe heat exchangers is considered.