I need help in 2 questions

1 answer below »

Answered Same Day Dec 25, 2021

Solution

David answered on Dec 25 2021

130 Votes

Solution-1:
Given data:
Water;
Mass flow rate of liquid water, mw = 4.45 X 10
5 kg/hr = 123.6 kg/s
Inlet – Liquid water pressure and temperature, Pw1, Tw1 = 7 Mpa, 285
oC
Outlet – Saturated vapor
Gas stream;
Inlet temperature, Tg1 = 1107
oC
Inlet pressure, Pg1 = 1 atm
Outlet temperature, Tg2 = 547
oC
Specific heat, CP,g = 1.005 kJ/kg-K, Cv,g = 0.718 kJ/kg-K
(a).
Inlet and outlet conditions are given so we can do heat balance to calculate the mass flow rate of the
gas stream
As we can see from thermodynamic table, at pressure of 7 MPa the saturation temperature is 285.9oC
so liquid is saturated liquid at the inlet and at exit it is saturated vapor so pressure will remain constant.
# Temp Pressure Specific Volume Internal Energy Specific Enthalpy Specific Entropy
Quality Phase
2 285 7 0.001348 1253 1262 3.113 Compressed Liquid
Enthalpy of water at inlet, hw1 = 1262 kJ/kg
Similarly, from thermodynamic table at outlet for saturated vapor:
# Temp Pressure Specific Volume Internal Energy Specific Enthalpy Specific Entropy
Quality Phase
4 285.9 7 0.02737 2580 2772 5.813 1 Saturated Vapor
Enthalpy of vapor at outlet, hw2 = 2772 kJ/kg
By heat balance:
Heat taken by the liquid water = Heat given by the gas stream
( ) ( )

( )
( )

( )
( )

(b). Change in entropy for the gas stream;
Pressure of the gas remains constant.
So change in entropy of for an ideal gas is given by the formula;
( (

) (

))
( (

) )

(c). Rate of entropy generation is given by the formula:
Rate of entropy generation = Total change in entropy of water + Total change in entropy of gas

( )

( )

( )

...

SOLUTION.PDF

I need help in 2 questions

Solution

Answer To This Question Is Available To Download

Related Questions & Answers

Submit New Assignment