Question

A two-part compressor operates with steady state conditions. The
exit of the first part of the compressor is also the inlet of the
second part of the compressor. In the first part of the compressor,
air is compressed from 1.5 bar, 350 K to 5.5 bar with a mass flow
rate of 7.2 kg/sec. In the second part of the compressor, air is
compressed from 5.5 bar to 9.5 bar with a mass flow rate of 5.8
kg/sec. Each unit of mass passing from inlet to exit undergoes a
process described by pv^{1.36}=constant. Heat transfer
occurs from the air at a rate of 53.0 kJ/kg of air, to cooling
water circulating in a water jacket enclosing the first part of the
compressor. An additional heat loss from the second part of the
compressor air also occurs to the surroundings in the amount of
91.0 kJ/kg of air. If kinetic energy and potential energy changes
are negeligable, determine the compressor power in kW. Use table
A-22 for ideal gas air properties, assuming that specific heats are
variable with temperature, and are not constant.

Answer #1

n ideal air-standard Brayton cycle operates at steady state with
compressor inlet conditions of 290 K and 95 kPa and a fixed turbine
inlet temperature of 1650 K. For a compressor pressure ratio of 10,
determine:
(a) the exhaust temperature of the cycle, in K.
(b) the back work ratio.
(c) the net work developed per unit mass flowing, in kJ/kg.
(d) the heat addition per unit mass flowing, in kJ/kg.
(e) the thermal efficiency for the cycle.

1. A feedwater heater operating at steady state has two inlets
and one exit. At inlet 1, water vapor enters at p1 = 7 bar, T1 =
200oC with a mass flow rate of 40 kg/s. At inlet 2, liquid water at
p2 = 7 bar, T2 = 40oC, density = 992.260 kg/m3 enters through an
area A2 = 25 cm2. Liquid water at 7 bar with a density of 902.527
kg/m3 exits at exit 3 with a volumetric flow...

a compressor operates at steady state. air enters the
compressor with a mass flow rate of 28800 kg/h at .99 bar and 27C
and exits at 7.5 bar. the compressor operates adiabatically and the
effects of motion and gravity can be ignored. the compressor
isentropic efficiency is 70%. for exergy analysis the reference
state is To=27C Po=.99 bar. use ideal gas model for air (MW=28.97
kg/kmol)
a. determine required power for compressor in kW
b. determine rate of exergy destruction...

Refrigerant 134a enters an insulated compressor operating at
steady state as saturated vapor at -12oC with a
volumetric flow rate of 0.18 m3/s. Refrigerant exits at
9 bar, 70oC. Changes in kinetic and potential energy
from inlet to exit can be ignored.
Determine the volumetric flow rate at the exit, in m3/s,
and the compressor power, in kW.

A
geothermal heat pump is used in winter for space heating by getting
heat from the ground at 15 °C. The working fluid in the heat pump
is R134a. The compressor inlet is at 400 kPa and the compressor
exit is at 2 MPa and 60 C. The mass flow rate of the refrigerant is
0.1 kg / s and the temperature difference in the air flow in the
condenser section is 12 C. The refrigerant is subcooled to 15...

4.58 Air enters a compressor operating at
steady state with a pressure of 14.7 lbf/in^2, a temperature of 808
F, and a volumetric flow rate of 18 ft /s. The air exits the
compressor at a pressure of 90 lbf/in^2 Heat transfer from the
compressor to its surroundings occurs at a rate of 9.7 Btu per lb
of air flowing. The compressor power input is 90 hp. Neglecting
kinetic and potential energy effects and modeling air as an ideal
gas,...

Q1. An ideal jet engine with a compressor, combustion chamber,
turbine and converging nozzle was held stationary during an
experiment to measure thrust in a laboratory. The turbine is used
to drive the compressor. The atmospheric pressure and room
temperature in the laboratory is measured as 102 kPa and 283 K. The
gauge pressure at compressor exit is measured as 0.0781 bar and the
inlet air flow is 10.4414 l/s. The maximum temperature reached in
the jet engine is measured...

Air at 1 bar, 295 K, and a mass flow rate of 0.7 kg/s enters a
compressor operating at steady state and exits at 3 bar. During the
compressing from inlet to exit, the air experiences a polytropic
process as PV^n=constant. m=6, n=1.48.
(1) Determine the power required by the compressor.
(2) Determine the heat transfer between the compressor and the
surrounding.
(s) Determine the rate of exergy destruction. Kinetic and potential
energy effects are negligible. Let T_0 = 300...

Air at 1 bar, 295 K, and a mass flow rate of 0.7 kg/s enters a
compressor operating at steady state and exits at 3 bar. During the
compressing from inlet to exit, the air experiences a polytropic
process as PV^n=constant. m=6, n=1.48
(1) Determine the power required by the compressor.
(2) Determine the heat transfer between the compressor and the
surrounding.
(s) Determine the rate of exergy destruction. Kinetic and potential
energy effects are negligible. Let T_0 = 300...

An air compressor, operated at steady state, compresses air from
1 bar 25oC to 10 bar. At the outlet of the compressor,
the air temperature is 80oC. The compressor transfers
heat to the surroundings at 300kJ for each kg of air passing
through the compressor. The average temperature at which the heat
is transferred is 50oC. Which of the following values is
closest to the specific entropy production of the compressor
process? For air, Cp=1.01 kJ/kgK and R=0.286kJ/kgK. Hints: Air...

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