The work is devoted to ensuring the completeness of mixing of gas coolants into a direct-acting heat exchanger by optimizing the geometry of the mixing chamber, in particular the addition of a funnel. Four funnel configurations in the range of 45°-180° are considered. The problem is solved in a stationary formulation by numerical simulation in the OpenFOAM environment. A 14-fold increase in the uniformity of mixing is shown when using a 45° funnel compared to a cylindrical mixing chamber.

Keywords: heat exchanger, mixing heat exchanger, efficiency improvement, outgoing flue gas, numerical modeling, heat recovery