III.  Flow with liquid spray injection (steady).

3.1-Physical Problem Description

The probem geometry and flow conditions in this chapter are as describe in the first point, except that the flow is no longer isothermal and the incoming air is at a temperature of 350 K. The additionnal physical complexity comes from the fact that a water spray is injected at the inlet to increase the concentration of the water vapour in the air stream. The amount of liquid injected is 6.09 10^-6 kg/s. The phisical properties of the liquid
and the initial droplet diameter, temperature and velocity are as follows :

 Density (kg/m3) Specific heat J/(kg K) Latent heat of vaporisation (J/kg) Pressure of saturation (Pa) Surface tension coefficient (M/m) Diameter (m) Initial temperature (K) Initial velocity (m/s) 995 4179 24.25 E5 4858 0.072 4.0 E-5 305 (-10.,10.,0.)

3.2-Modelling strategy

The following modelling strategy model is adopted :

• The total number of droplets entering the domain is 182.703 per second. These are grouped into 30 parcels with identical initial conditions.
• Droplets rebound perfectly when they hit a wall.
• The standard turbulence model for Lagrangian flow is used.
• Gravity efffects are neglected.
• Droplets exchange momentum, heat and mass with the continuous phase.
• The effect of evaporated droplet mass on the density of the continuous phase is assumed to be neglected.
3.3-Computing and results.

Here are some results :

fig 1 : Trajectories of particles with liquid spray injection location (red ball)

fig  2 : Vapour concentration & plot tracks

fig 3 :  Vapour concentration at z= 0.4

fig 4 :  Vapour concentration at z= 0.8