Question

A steam turbine has inlet steam pressure p_{1} = 1.4 MPa
absolute. Inlet steam temperature is T_{1} = 400
^{o}C. This corresponds to inlet enthalpy per unit mass of
h1 = 3121 kJ/kg. Exit pressure of the steam is p_{2} = 101
kPa absolute. Exit steam temperature is T_{2} = 100
^{o}C. This corresponds to exit enthalpy per unit mass of
h_{2} = 2676 kJ/kg. Inlet speed of the steam is
V_{1} = 15 m/s and exit speed is V_{2} = 60 m/s.
Axis of the steam turbine is horizontal. Time-rate of heat loss
through the walls of the turbine is Q = 7600 kJ/h. The mass flow
rate of steam through the turbine is 0.5 kg/s.

a) If the power extracted by the turbine is P_{actual} =
200 kW, what is the amount of power loss (expressed in kW) due to
viscous effects?

b) If there would be no viscous losses, what would be the ideal
power, P_{ideal}, extracted by the turbine (in kW)?

c) What is the coefficient of efficiency, ?, of the turbine?

Answer #1

Steam flows steadily through an adiabatic turbine. The inlet
conditions are: 20 MPa, 500°C, 90 m/s and the exit conditions are
20 kPa, 95% quality, and 60 m/s. The mass flow rate of the steam is
15 kg/s. Find:
a) The change in kinetic energy of the steam, (5 points)
b) The power output, and (5 points)
c) The turbine inlet area. (5 points)

Steam at 4.5 MPa and 500 C enters the turbine with a velocity of
60 m/s and its mass flow rate is 5,000 kg/h. The steam leaves the
turbine at a point 3m below the turbine inlet with a velocity of
350 m/s. The heat loss from the turbine is 100,000 kJ/hr and the
shaft work produced is 950hp. A small portion of the exhaust steam
from the turbine is passed through a throttling valve and
discharges at atmospheric pressure....

P2) Steam flows steadily through an adiabatic turbine in a power
plant. The inlet conditions of the steam are 6 MPa, 400 °C and 119
cm2 . The exit conditions are 40 kPa, 92 percent quality, 50 m/s
and 20 kg/s. Determine the power output.

A steam turbine receives steam from two boilers.
One flow is 5 kg/s at 3 MPa, 700°C and the other flow is 15 kg/s
at 800 kPa, 500°C.
The exit state is 10 kPa, with a quality of 96%.
The actual power output is 22MW.
A steam turbine receives steam from two boilers.
One flow is 5 kg/s at 3 MPa, 700°C and the other flow is 15 kg/s
at 800 kPa, 500°C.
The exit state is 10 kPa, with...

13) A turbine, operating under steady-flow
conditions, receives 5000 kg of steam per hour. The steam enters
the turbine at a velocity of 3000 m/min, an elevation of 5 m and a
specific enthalpy of 2787 kJ/kg. It leaves the turbine at a
velocity of 6000 m/min, an elevation of 1 m and a specific enthalpy
of 2259 kJ/kg. Heat losses from the turbine to the surroundings
amount to 16736 kJ/h. Determine the power output of the
turbine.
14) 12 kg...

Steam with pressure 6 MPA and temperature 500 ⁰C expands
in an adiabatic turbine to saturated steam and a pressure of 0,3
MPA. Kinetic energy and potential energy is neglected. Determine
work produced, entropi generated and exergy destroyed for the
turbine. Assume surrounding to 0,1 MPa och 25 ⁰C.

Steam at 6 MPA, 600°C, enters a well-insulated turbine operating
at steady state and exits at 0.1 bar. The isentropic efficiency of
the turbine is 94.7%. Assuming the kinetic and potential energy
effects to be negligible, determine:
(a) Work output, in kJ/kg,
(b) The temperature at the exit of the turbine, in °C, and
(c) The rate of entropy production within the turbine, in kJ/K
per kg of steam flowing through the turbine.
(All steps required – Given/Find/Schematic/Engineering
Model/Analysis)
THANK...

Consider now a turbine(Q=0) that operates with
N2 steam with T1 = 753.15K and P1 = 6 bar and P2 = 1 bar. The
efficiency is 80% and the molar flowrate is (note not mass flow
rate) is 200 mol/s. The inlet velocity is 30 m/s and the exit
velocity is 120 m/s. The inlet is 6 m above the base of the turbine
and the exit is 2 m above the base.
a. Determine the output of the turbine...

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...

Steam enters an adiabatic turbine at 140 bar and 560 C and
leaves at 10 kPa. At the exit, the pressure and quality are 50 KPa
and .90, respectively. Determine the power produced (kW) by the
turbine if the mass flow rate is 1.63 kg/s.

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