Spray and Two-Phase Flames

In many technical applications, liquid fuels play an important role, e.g., for the operation of petrol and diesel engines, turbines or a variety of industrial furnaces. Often these fuels enter the combustion chamber as a spray which then evaporates and mixes with the gaseous oxidizer. However, also for in principle purely gaseous combustion processes the addition of a liquid phase can be important, e.g., to extinguish flames or fires by the addition of liquid water.

Cosilab is able to simulate such spray or two-phase flames.

As one example, the following two figures show computed flamespeeds for a premixed propane-air flame with two different amounts of liquid water added to the fresh, unburnt mixture as a function of the equivalence ratio. In each figure, the parameter is the initial droplet size.

Profiles through a premixed, freely propagating spray flame of a few, selected quantities are shown in the following figure, namely the profiles of liquid-phase and gasphase temperature, the profiles of the massfractions of O, H and OH, and the profiles of liquid-phase and gasphase velocity. The left column of pictures is for an equivalence ratio of unity, the right column for an equivalence ratio of 1.25.