Evolution of the hot gas at the first pass of a fire tube steam boiler

The gas produced by the burner proceeds along the furnace tube and is hosted into the chamber before entering the fire pipes. Gas temperature and speed are key issues to drive the selection of the materials to be used for construction.

The study has been developed with the contribution of Bono Energia, established Italian company making fire tube boilers since 1958.


Aim of the project: modeling of the hot gas fluid dynamics evolving in the reversal chamber.


  • Basing on the boiler geometry, a numerical model is developed including all elements and volumes involved in the phenomenon.
  • Experimental indications about the operating conditions are provided by the customer and are coherently imposed to the model.
  • The thermo-/fluid-dynamics of the gas evolution is modeled and the pressure, temperature and speed inside the reversal chamber are mapped.