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

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
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,...

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...

Carbon dioxide (CO2) gas is compressed at steady state from 0.8
bar and 17 °C to 3.5 bar with a compressor drawing 10 kW of power.
The CO2 flows through the compressor at a rate of 0.1 m3/s through
an inlet orifice that is 200 cm2. The gas leaves the compressor at
a velocity of 12 m/s. Heat loss from the compressor to the
surroundings is roughly 2% of the power fed to the compressor. In
addition to the Give,...

Air enters a compressor operating at steady state at 15.4
lbf/in^2, 80°F with a volumetric flow rate of 424 ft^3/min and
exits at 176.4 lbf/in^2, 260°F. Heat transfer occurs at a rate of
6800 Btu/h from the compressor to its surroundings. Assuming the
ideal gas model for air and neglecting kinetic and potential energy
effects, determine the power input, in hp.

1) A nozzle is a device for increasing the velocity of a
steadily flowing stream of fluid. At the inlet to a certain nozzle
the enthalpy of the fluid is 3025 kJ/kg and the velocity is 60 m/s.
At the exit from the nozzle the enthalpy is 2790 kJ/kg. The nozzle
is horizontal and there is negligible heat loss from
it.
(i) Find the velocity at the nozzle exit.
(ii) If the inlet area is 0.1 m2 and specific volume...

A vapor-compression refrigeration cycle operates at steady state
with Refrigerant 134a as the working fluid. Saturated vapor enters
the compressor at 2 bar, and saturated liquid exits the condenser
at 8 bar. The isentropic compressor efficiency is 80%. The mass
flow rate of refrigerant is 7 kg/min. Determine: (a) the compressor
power, in kW, (b) the refrigeration capacity, in tons, (1 ton =
3.5168 kW) and, (c) the coefficient of performance, (d) rate of
entropy production in kW/K, for the...

A horizontal steady-state turbine is being designed to serve as
an energy source for a small electrical generator. (assume its
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1037 kW. The inlet to the turbine is steam at T1 = 600 0 C and P1 =
10 bar, with a mass flow rate of 2.5 kg/s. The inlet pipe is 10 cm
in diameter. The conditions at the turbine exit are T2 = 400 0 C
and P2...

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