Consider 100 kg/s of steam expanding in a turbine. The inlet to the turbine is at 15 MPa, 500 degrees C. The steam expands to 0.01 MPa. The exit entropy is 6.200 kJ/(kg.K). Though the turbine is well insulated, at a place where the temperature is 127 degrees C, a loss of insulation leads to a heat loss of 8 MW.
8 answers
What's the question?
1.What is the entropy production rate (in kW/K)?
2.If the process is possible, what is the outlet dryness fraction?
3.if the process is possible, what is the power output of the turbine, in MW?
2.If the process is possible, what is the outlet dryness fraction?
3.if the process is possible, what is the power output of the turbine, in MW?
1)
m(s2-s1) = dQ/T + S_gen
m(s2-s1) = (-8*10^6W)/(127+273) +S_gen
find s1 at P=15MPa and T1=500+273.2
(super heated water vapor)
s2=6.200 KJ/kg-K
you will need to interpolate to find s1:
plug all values in to find s_gen, the entropy production rate
3) apply first law:
-Q_L - W = m*(h2-h1)
Q_L = 8MW
find h2 and h1 in charts in back of book
then solve for W
m(s2-s1) = dQ/T + S_gen
m(s2-s1) = (-8*10^6W)/(127+273) +S_gen
find s1 at P=15MPa and T1=500+273.2
(super heated water vapor)
s2=6.200 KJ/kg-K
you will need to interpolate to find s1:
plug all values in to find s_gen, the entropy production rate
3) apply first law:
-Q_L - W = m*(h2-h1)
Q_L = 8MW
find h2 and h1 in charts in back of book
then solve for W
plzzz give the answer onlyyyy
Follow those steps. 90% of the work is done for you already..
Consider 2 kg of an ideal gas (R=300 J/(kg.K) and Cp=1000 J/(kgK)) contained in a piston cylinder arrangement. The cylinder has a small valve at the end opposite to the piston.The cylinder walls are not adiabatic and allow heat transfer. The initial pressure and volumeare 0.1 MPa and 2 m^3. At time t=0, the gas starts leaking extremely slowly (at theconstant rate of 0.001 kg/s) through the valve (the opening of the valve can be assumed to be controlled to allow a constant leak rate) while the piston is allowed to move. The piston can be considered frictionless. The leakage stops at t=1000s. The whole process can be considered to take place quasistatically with local equilibrium being achieved instantly within the cylinder.The pressure and temperature of the gas do not change during this process.
Answer the following questions.
4A. What is the final volume of the gas (in m3) ?
4B. What is the heat transfer during the process (in joule)?
4C. What is the change in the specific entropy of the gas in the cylinder(in J/(kg.K))?
4D. What is the entropy production rate, in kW/K?
Answer the following questions.
4A. What is the final volume of the gas (in m3) ?
4B. What is the heat transfer during the process (in joule)?
4C. What is the change in the specific entropy of the gas in the cylinder(in J/(kg.K))?
4D. What is the entropy production rate, in kW/K?
Can some one send the answer
Q NO 4A. ANS IS 1
Q NO 4B. ANS IS 0
Q NO 4C. ANS IS 0
Q NO 4D. ANS IS 0
Q NO 4B. ANS IS 0
Q NO 4C. ANS IS 0
Q NO 4D. ANS IS 0
0 answers