1) Air enters the return air duct in a climate control system operating at steady state with a volumetric flow rate of 60 m3/min at a temperature of 22oC and a pressure of 1.2 bar. Outside air at -13oC is mixed with the return air producing a stream that enters the heating unit of the climate control system. The ratio of the mass flow rate of outside air to return air is 0.15. Assuming no heat transfer in the mixing process, neglecting kinetic and potential energy effects, and assuming ideal gas behavior, determine the temperature of the air entering the heating unit, in oC, and the corresponding mass flow rate, in kg/min.
2) Carbon dioxide (CO2) enters a well-insulated nozzle with negligible velocity at 330 K and 8 bar. The gas exits the nozzle with a velocity of 263.6 m/s at 4.424 bar through an exit area of 7 cm2. Assume the carbon dioxide is an ideal gas with a constant specific heat ratio of k = cp/cv = 1.26 and neglect potential energy effects. For steady state operation, determine the mass flow rate, in kg/s.