6. Two air flows are combined to a single flow. One flow is 1 m3/s at 20 oC and the other is 2 m3/s at 200 oC, both at 100 kPa. They mix without any heat transfer to produce an exit flow at 100 kPa. Neglect kinetic energies and find the exit temperature and volume flow rate.

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Explanation:

This is a case of a mix chamber, which is modelled after the First Law of the Thermodynamics:

According to the Principle of Mass Conservation:

Let assume that air behaves as an ideal gas. The density has the following expression:

Densities at inlets are, respectively:

The mass flow at outlet is:

Specific enthalpies depends on temperature only. The required variable for inlet are obtained from property tables:

Specific enthalpy at outlet is:

The exit temperature is:

The density of air at outlet is:

The volume flow rate at outlet is:

come closer and become far apart and become steam/gas