The pressure, temperature and velocity of air flowing in pipe are 5 bar, 500 K and 50m/s, respectively. The specific heats of air at a constant pressure and at constant volume are 1.005 kJ/kgK and 0.718 kJ/kgK, respectively. Neglect potential energy. If the pressure and temperature of the surroundings are 1 bar and 300 K, respectively, the available energy in kJ/kg of he air stream is

Q. Dew point temperature of air at one atmospheric pressure (1.013 bar) is ${18}^{\circ }C$. The air dry bulb temperature is ${30}^{\circ }C$. The saturation pressure of water at ${18}^{\circ }Cand{30}^{\circ }C$ are 0.02062 bar and 0.04241 bar respectively. The specific heat of air and water vapour respectively are 1.005 and 1.88 kJ/kgK and the latent heat of vaporization of water at $0^{\circ }C$ is 2500 kJ/kg. The specific humidity (kg/kg of dry air) and enthalpy (kJ/kg of dry air) of this moist air respectively, are

Q. An air standard Otto cycle has a compression ratio of 8 and temperature and pressure at the begining of compression are ${20}^{0}C$ and 1 bar respectively . The constant volume heat addition is 1800 kJ/kg . Take $C_V$ = 0.718 and y = 1.4 . The maximum pressure for the cycle is :

Q. 1 kg of air is compressed polytropically from 1 bar pressure and temperature of 300 K to a pressure of 6.8 bar and temperature of 370 K.

Assume

$R=0.287kJ/kgK,c_p=1.005kJ/kgK,c_v=0.716kJ/kgK$. If the sink temperature is 293 K the reversible work done by air is _____ $kJ/kg$.

Q. A regenerative Brayton refrigeration working between pressure limit of 1 and 3 bar. The temperature and pressure of air at inlet of compressor is 270 K and 1 bar respectively. Compressed air enters regenerative heat exchanger at temperature of 310 K and exit at a temperature of 280 K. The refrigeration effect is 30 kJ/kg. The effectiveness of heat exchanger is ____.
Assume compression and expansion are isentropic
(Take $\gamma$ for air = 1.4 and $c_p$ for air = 1.005 kJ/kgK)
(Correct upto 3 decimal place)