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Air at 30 °C and 120 kPa enters a compressor operating at steady state
$1.00Air at 30 °C and 120 kPa enters a compressor operating at steady state and exits at 250 °C and 620 kPa. Stray heat transfer and kinetic and potential energy effects are negligible.
Determine the:
a. Temperature in degrees K at the exit of the compressor if the compressor operates
isentropically, i.e. T2s
Ans. 484.6 K
b. Isentropic compressor efficiency Ans. 82.5%Water at 20 bar, 400 degree C enters a turbine…
$1.00Water at 20 bar, 400 degree C enters a turbine operating at steady state and exits at 1.5 bar. Stray heat transfer and kinetic and potential energy effects are negligible. A hard-to-read data sheet indicates that the quality at the turbine exit is 98%. Can this quality value be correct? If no. what could the quality be? If yes. determine the power developed by the turbine, in kJ per kq of water flowing. Ans: No. 98.33% minimum
A turbine is operated at steady state generating…
$1.00A turbine is operated at steady state generating the power of 2626 kW. Water vapor at 6 MPa, 600°C enters it and expands to 10 kPa. The mass flow rate is 2 kg/s. Stray heat transfer and kinetic and potential energy effects are negligible.
Determine (a) the quality at the exit, (b) the isentropic turbine efficiency and (c) the rate of entropy production within the turbine, in kW/K
A car driving along a highway at a speed of 22.9 m/s strays onto the shoulder
$0.00A car driving along a highway at a speed of 22.9 m/s strays onto the shoulder. Evenly spaced parallel grooves called “rumble strips” are carved into the pavement of the shoulder. Rolling over the rumble strips causes the car’s wheels to oscillate up and down at a frequency of 87.0 Hz. How far apart are the centers of adjacent rumble-strip grooves?
mPlease provide explanation and answer.
Determine the power developed by the turbine
$1.00Water at 20 bar, 400°C enters a turbine operating at steady state and exits at 1.5 bar. Stray heat transfer and kiniteic and potential energy effects are negligible. A hard-to-read data sheet indicates that the quality at the turbine exit is 98%. Can this quality value be correct? If no, explain. If yes, determine the power developed by the turbine, in KJ per kg of water flowing.
Air modeled as an ideal gas enters a turbine operating at steady state
$1.00Air modeled as an ideal gas enters a turbine operating at steady state at 1040 K, 278 kPa and exits and 120 kPa. The mass flow rate is 5.5 kg/s, and the power developed is 1120kW. Stray heat transfer and kinetic and potential energy effects are negligible. Determine (a) the temperature of the air at the turbine exit, in K, and (b) the isentropic turbine efficiency.
Would it be possible to pump 68 kg of water in one minute
$1.00A 25-hp pump operating at steady state receives liquid water at 50?C, 1.5 MPa. The pressure of the water at the pump exit is 15 MPa. Stray heat transfer and changes in kinetic and potential energy are negligible. Would it be possible to pump 68 kg of water in one minute? If so,determine the isentropic efficiency of the pump having that mass flow rate. If not, what is the maximum mass flow rate achievable with this pump?
Steam enters a turbine operating at steady state at a pressure of 1000
$1.00Steam enters a turbine operating at steady state at a pressure of 1000 lbf/in2 and a temperature of 1100°F, and exits at a pressure of 4.0 lbf/in2 as a saturated liquid-vapor mixture with a quality of 0.96. Stray heat transfer from the turbine to the surroundings occurs. The ambient temperature is 90°F. Measurements indicate that the magnitude of the rate of the stray heat transfer is 3% of the turbine power. The mass flow rate of water through the turbine is 10 lbm/s.
(a) Calculate the turbine power (Btu/s).
(b) For an enlarged control volume that includes the turbine and enough of the surroundings so that the boundary temperature is 90°F, calculate the rate of entropy production (Btu/s-°R).Please show work. Final answer for A) 4620 Btu/s; (B) 1.31 Btu/s·R
EGR 334 Homework solutions HW Set 26
$7.00EGR 334 HW Set 26
Problem 6: 80
A gas flows through a 1-inlet, 1-outlet control volume operating at steady state. Heat transfer at the rate Qdotcv takes place only at a location on the boundary where the temperature is Tb. For each of the following cases, determine whether the specific entropy of the gas at the exit is greater than, equal to, or less than the specific entropy of the gas at the inlet.
- a) no internal irreversibilities, Qdotcv = 0
- b) no internal irreversibilities, Qdotcv < 0
- c) no internal irreversibilities, Qdotcv > 0
- d) no internal irreversibilities, Qdotcv >= 0
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EGR 334 HW Set 26
Problem 6:86
By injecting liquid water into superheated steam, the desuperheater shown has a saturated vapor stream at its exit. Steady state operating data are provided in the accompanying table. Stray heat transfer and all kinetic and potential energy effect are negligible. a) Locate states 1, 2, nd 3 on a sketch on the T-s diagram. b) Determine the rate of entropy production within the desuperheater in kW/K.
State p(MPa) T(deg C) v(m3/kg) u(kJ/kg) h(kJ/kg) s(kJ/kg-K) 1 2.7 40 0.0010066 167.2 169.9 0.5714 2 2.7 300 0.09101 2757.0 3002.8 6.6001 3 2.5 sat. vapor 0.07998 2603.1 2803.1 6.2575 —————————————————————————————————————–
EGR 334 HW Set 26
Problem 6:91
Steam at 240 deg C and 700 kPa enters an open feedwater heater operating at steady state with a mass flow rate of 0.5 kg/s. A separate stream of liquid water enters at 45 deg C, 700 kPa with a mass flow rate of 4 kg/s. A single mixed stream exits at 700 kPa and temperature T. Stray heat transfer and KE and PE can be ignored. Determine
- a) T, in deg C and
- b) the rate of entropy production within the feedwater heater in kW/K.
- c) Locate the three principal states on a sketch of the T-s diagram.
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EGR 334 HW Set 26
Problem 6: 111
The figure show data for a portion of the ducting in a ventilation system operating at steady state. The ducts are well insulated and the pressure is very nearly 1 atm throughout. Assuming the ideal gas law for air with cp = 0.24 Btu/lb-R and ignoring KE and PE, determine
- a) the temperature of the air at the exit in deg F.
- b) the exit diameter in ft
- c) the rate of entropy production within the duct in Btu/min-R.
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