Answer:
Explanation:
Obtain the following properties at 6MPa and 600°C from the table "Superheated water".
Obtain the following properties at 10kPa from the table "saturated water"
Calculate the enthalpy at exit of the turbine using the energy balance equation.
Since, the process is isentropic process 
Use the isentropic relations:
Calculate the enthalpy at isentropic state 2s.
a.)
Calculate the isentropic turbine efficiency.
b.)
Find the quality of the water at state 2
since 
at 10KPa <
<
at 10KPa
Therefore, state 2 is in two-phase region.
Calculate the entropy at state 2.
Calculate the rate of entropy production.
since, Q = 0
Answer:
a) 1253 kJ
b) 714 kJ
c) 946 C
Explanation:
The thermal efficiency is given by this equation
η = L/Q1
Where
η: thermal efficiency
L: useful work
Q1: heat taken from the heat source
Rearranging:
Q1 = L/η
Replacing
Q1 = 539 / 0.43 = 1253 kJ
The first law of thermodynamics states that:
Q = L + ΔU
For a machine working in cycles ΔU is zero between homologous parts of the cycle.
Also we must remember that we count heat entering the system as positiv and heat leaving as negative.
We split the heat on the part that enters and the part that leaves.
Q1 + Q2 = L + 0
Q2 = L - Q1
Q2 = 539 - 1253 = -714 kJ
TO calculate a temperature for the heat sink we must consider this cycle as a Carnot cycle. Then we can use the thermal efficiency equation for the Carnot cycle, this one uses temperatures:
η = 1 - T2/T1
T2/T1 = 1 - η
T2 = (1 - η) * T1
The temperatures must be given in absolute scale (1453 C = 1180 K)
T2 = (1 - 0.43) * 1180 = 673 K
673 K = 946 C
Answer:
False
Explanation:
The government decides the productions.
