Section: Thermodynamics | Marks: 2
An air-conditioning system consists of an insulated rigid mixing chamber designed to supply air at 24 ℃ to a building. The mixing chamber mixes two air streams: (i) a cold air stream at 10 ℃ and mass flow rate c m&(kg/s), and (ii) a stream of fresh ambient air at 30 ℃ and mass flow rate a m&(kg/s). Assume air to be an ideal gas with constant specific heat ( 1.005 kJ/(kg K), / 1.4 p p v c c c γ = = = ). Neglect change in kinetic and potential energies as compared to change in enthalpy. Under the steady state condition, the ratio of the mass flow rates of the two streams ( / c a m m & &) is
- A. 7 3
- B. 3 7
- C. 2 7
- D. 4 7
Answer: B. 3 7