# Adiabatic mixing of airstreams

1. Jan 6, 2010

### Appa

I'm having a lot of trouble with an adiabatic mixing process.
This is what I know:
There's an airstream coming from outside and its temperature is T1=5 'C, its relative humidity being $$\varphi$$1= 90% at a rate of 20 m3/min.
Another airstream is coming from inside and its temperature is T2= 25 ´C, relative humidity $$\varphi$$2= 50%, at the rate of 20 m3/min.
The airstreams are mixed in a chamber with the pressure p = 1 bar.
I should find the densities of the first and second mixtures (meaning the airstreams including the water). This I've accomplished, the densities being $$\rho$$1=1.249 kg/m3 and $$\rho$$2= 1.162 kg/m3. I've also found the mass rates for the water in both streams; $$^{.}$$mw1= 2.0 g/s and m$$^{.}$$w2= 3.8 g/s.

What I havent been able to find is this: the specific humidity $$\omega$$3 of the mixed airstreams. I simply don't know what to do: I've tried finding first the specific humidities of the airstreams before mixing and stuff like that, but I just can't get the right result! This is what it should be: $$\omega$$3= 7.36*10-3 kg H2O/kg air.