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.

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?

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?

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

plzzz give the answer onlyyyy

Follow those steps. 90% of the work is done for you already..

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

To solve this problem, we need to use the steam tables to find the properties of steam at the inlet and exit conditions, and then apply the first law of thermodynamics to calculate the heat loss.

1. Find the properties of steam at the inlet conditions:
Using either the saturated or superheated steam tables, we can find the properties of steam at a pressure of 15 MPa and a temperature of 500 degrees C. Look up the specific enthalpy (h) and specific entropy (s) values.

2. Find the properties of steam at the exit conditions:
Similar to step 1, use the steam tables to find the properties of steam at a pressure of 0.01 MPa. Look up the specific enthalpy (h) and specific entropy (s) values.

3. Apply the first law of thermodynamics (energy balance):
The first law of thermodynamics states that the change in internal energy (ΔU) of a system equals the heat transfer (Q) into the system minus the work done (W) by the system. In this case, since the turbine is well insulated, Q = 0.

Therefore, ΔU = -W.
The change in internal energy can be calculated using the specific enthalpy values obtained in steps 1 and 2.

4. Calculate the heat loss:
Since the turbine is insulated except for the region where the heat loss occurs, the heat loss can be expressed as thermal efficiency (η) times the energy input to the turbine (here 100 kg/s * ΔU).

Therefore, Heat loss = (1 - η) * Energy input to the turbine.

Plug in the value of the heat loss (8 MW) and solve for the energy input to the turbine.

5. Calculate the thermal efficiency:
The thermal efficiency of the turbine can be calculated using the first law of thermodynamics and the properties of steam at the inlet and exit. Thermal efficiency = (W / Energy input to the turbine).

Plug in the values of work done calculated in step 3 and the energy input to the turbine obtained in step 4, and solve for the thermal efficiency.

Now that we have a step-by-step approach to solving the problem, you can follow these steps to find the answers.