1 kg / s of steam is compressed in an adiabatic compressor from
200 kPa and 200 ° C to 3000 kPa and 400 ° C. How powerful is the
compressor? is this transformation possible (briefly argue)?
air is compressed in an adiabatic and isentropic compressor from
14 psia and 60F to 210 psia. Determine the outlet temperature [F]
and the work consumed by this compressor per unit mas of air
[Btu/lbm]. Assume constant specific heats at T=100F
Please explain table look ups, thank you!
Refrigerant 134a enters an air conditioner compressor at 4 bar,
20°C, and is compressed at steady state to 12 bar, 80°C. The
volumetric flow rate of the refrigerant entering is 7.5 m3/min. The
work input to the compressor is 112.5 kJ per kg of refrigerant
flowing. Neglecting kinetic and potential energy effects, determine
the magnitude of the heat transfer rate from the compressor, in
kW.
Steam at 400°C and 40 bar flows steadily through an adiabatic
turbine at a volumetric
flowrate of 5,000 m3/h. The steam leaving the turbine at 1 bar is
then cooled at constant
pressure in a condenser to 25°C. The rate of transfer from the
condenser is 50 MW.
Calculate the power output generated by the turbine (MW). Clearly
state assumptions (if
any) and reference state.
Refrigerant-134a enters an adiabatic compressor as saturated
vapor at 160 kPa at a rate of 2.8 m3/min and is
compressed to a pressure of 900 kPa. Determine the minimum power
that must be supplied to the compressor. Use the tables for
R-134a.
The minimum power that must be supplied to the compressor
If the steam is now expanded from 10 bar and 500 degree Celsius
to 0.04 bar with isentropic efficiency of 90%, in what respects
does the ideal gas assumption become invalid. Compare the ideal gas
and steam table results for the exit temperature and the work
output
Steam, initially at 15 bar and 250oC and stored in a rigid
container, is reversibly compressed at constant temperature. During
the compression, the steam receives 400 kJ/kg of work. Determine ??
and the final state of the steam. Thermodynamic data: NIST
Chemistry WebBook (Thermophysical Properties of Fluid Systems)
One mole of an ideal gas (CP/R=7/2), is
compressed in a steady-flow compressor from 2.5 bar and 25°C to 6.5
bar and 120°C. The compressor rejects 0.5 kJ as heat to the
surrounding at 293K.
Calculate:
1. The enthalpy
change of the gas (in kJ)
2. The entropy
change of the gas (in J.mol-1)
3. The work
required for the compression (in kJ)
4. The ideal work
of the process (in kJ)
5. The
thermodynamic efficiency
The lost work (in kJ)
Steam enters an adiabatic turbine steadily at 3 MPa and
400°C and leaves at 50 kPa. If the isentropic efficiency of the
turbine is 66.7%, determine the actual temperature of steam at
turbine exit. The mass flow rate of the steam flowing through the
turbine is 218 kg/min, determine the power output from the turbine.
Plot the T-s diagram.
In a gas turbine plant, air is compressed from 1.01 bar and 15
?C through a pressure ratio of 4. It is then heated to 650 ?C in a
combustion chamber, and expanded back to atmospheric pressure.
Calculate the cycle efficiency and work ratio if a perfect heat
exchanger is employed. The isentropic efficiencies of the turbine
and compressor are 0.85 and 0.80, respectively. ANSWER (0.319,
0.319)