Question

Nitrogen expands in a turbine at a rate of 0.17 kg/s. The nitrogen enters the turbine at 750 kPa, 580 K and it exits at 195 kPa, 323 K. The power delivered by the turbine is measured to 38 kW. Neglect potential and kinetic energies. For Nitrogen, Cp = 1039 j/Kg.k

1. Calculate the amount of heat transfer.

2. Determine if the heat is added to the system or lost from the system.

3. Plot the TV diagram showing all the states and numbers on it.

Answer 1

Griven i © 'turbine expansion of Nitrogen, flow rate, in 0.17 kg/s. Pressure, Pi 150 kPa P2 = 195 kPa Temperature, Ti = 580k mo T2= 383k. Power delivered, lat = 38 kW. (p= 1039 g/kgk. Gas constant for Nitrogen, R = 0.896 kJ/reck tunt rart au Solution : steady flow energy equation is, m2 +W. mbi tmg zit ma + Q = mba+mg Z₂+ 2000 2000 kinetii & polintial energies negligible longing ( mhi to = mbath. CPT) (0.17% 1.039 x 580) + @ = (0,17 x 1.0394523) + 38. = 57.051 +38 - 102.44. Q Q = - 7.389 kW.

1. amount of heat bransfera Q = -7.389 KW. a. Heat is lost from the system. Because of regative sign. 3. TV diagram : we know that, PV = MRT MRTI Р. O.17 x0.296x580 Vio 750 V = 0.0389 m/s V2 = MRT2 0.17 x 0.296 *323 P2 195 V2 = 0.0833 m/ Sono andalar Temperatur 58031 20.11. 323K 0.0389 0.0833 volume (m/)