Question

Refrigerant-134a enters a diffuser steadily as saturated vapour at
600 kPa with a velocity of 160 m/s, and it leaves at 700 kPa and
40°C. The refrigerant is gaining heat at a rate of 2 kJ/s as it
passes through the diffuser : determine

(a- the exit velocity

(b- the mass flow rate of the refrigerant.

If the exit area is twice the inlet area (A2=2A1),

Answer #1

Nitrogen gas at 50 kPa and 7°C enters an adiabatic diffuser
steadily with a velocity of 180 m/s and leaves at 109 kPa and 22°C.
Determine (a) the exit velocity of the nitrogen and (b) the ratio
of the inlet to exit area A1/A2

Nitrogen gas at 60 kPa and 78C enters an adiabatic diffuser
steadily with a velocity of 275 m/s and leaves at 85 kPa and 278C.
Determine (a) the exit velocity of the nitrogen and (b) the ratio
of the inlet to exit area A1/A2. Reconsider Using EES (or other)
software, investigate the effect of the inlet veloc- ity on the
exit velocity and the ratio of the inlet-to-exit area. Let the
inlet velocity vary from 210 to 350 m/s. Plot...

A saturated vapor of refrigerant 134a at 1000 kPa enters a
nozzle with a negligible velocity. It leaves the nozzle at 500 kPa.
What is the maximum velocity it could have, in m/s?
Hint: Remember that a nozzle does an energy
conversion. The maximum velocity occurs when this is being done
with the highest possible efficiency. What did you learn about
entropy when efficiency is at a maximum?

Air
at 10º C and 80kPa enters the diffuser of a jet engine steadily
with a velocity of. 200 m/s. The inlet area of the diffuser is 0.5
m. 2 . The air leaves the diffuser with a velocity that is very
small compared with the inlet velocity. Determine a).the mass flow
rate of the air b).the temperature of the air leaving the
diffuser.

An ice-making machine operates on the ideal vapor-compression
cycle, using R-134a. The refrigerant enters the compressor as
saturated vapor at 140 kPa and leaves the condenser as saturated
liquid at 600 kPa. Water enters the ice machine at 13oC and leaves
as ice at -4oC, while removing heat at 393 kJ per kg of water.
Estimate the mass flow rate of the refrigerant and the power input
to the ice machine for an ice production rate of 7 kg/h.

Steam enters a diffuser at 250°C and 300kPa with an inlet
velocity of 402 m/s. Steam leaves the diffuser at 350°C and 600kPa.
The heat gain in the diffuser is 80 kW. The inlet area of the
diffuser is 820 cm2. Determine the velocity and the
volume flow rate of the steam at the diffuser exit.

An unknown ideal gas enters a 25 cm-diameter pipe steadily at
250 kPa and 47C with a velocity of 5 m/s. The ideal gas gains heat
as it flows and leaves the pipe at 77C and 225 kPa. The gas
constant of the ideal gas is R=0.285 kJ/kg.K. Determine:
a) the volume flow rate at the inlet
b) the mass flow rate
c) the velocity at the exit

Water is used to cool R-134a in the condenser of a heat
exchanger. The refrigerant enters the counter-flow heat exchanger
at 800 kPa, 80 0C and a mass flow rate of 2 kg/s. The refrigerant
exits as a saturated liquid. Cooling water enters the condenser at
500 kPa and 18 0C and leaves the condenser at 30 0C. Determine the
necessary mass flow rate of water. Each fluid is assumed to flow at
constant pressure.

Refrigerant 134a enters a tube at a rate of 0.07 kg/s as
saturated liquid at 70 C and leaves the tube as saturated liquid as
well at -8 C. It loses 10 kW of heat to the surroundings in the
process. If the surroundings are at a temperature 10 C, find the
total entropy generation in this process. Assume steady
conditions

A commercial refrigerator with refrigerant-134a as the working
fluid is used to keep the refrigerated space at −30°C by rejecting
its waste heat to cooling water that enters the condenser at 18°C
at a rate of 0.32 kg/s and leaves at 26°C. The refrigerant enters
the condenser at 1.2 MPa and 65°C and leaves at 42°C. The inlet
state of the compressor is 60 kPa and −34°C and the compressor is
estimated to gain a net heat of 460 W...

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