Plate Heat Exchanger with Diffuser Ducts with Gas Heat-Transfer Agents

Numerical modeling of flow and heat transfer in heat exchangers with diffuser ducts with gas heat-transfer agents was carried out. Plate heat exchangers with small duct expansion angles that do not cause flow separation are considered. Due to enhancement of heat transfer in expanding ducts with an increase in the expansion angle, the heat transfer power increases in comparison with heat exchangers with a constant duct cross section. It is shown that when using air as a “cold” heat carrier, the heat transfer power increases with the growth of the heat capacity of “hot” gas heat-transfer agents. The calculations used a three-parameter RANS turbulence model supplemented by a turbulent heat flux equation.