In an open cycle gas turbine plant, air enters the compressor at 1 bar and 290 K. The pressure at the exit of compressor is 5 bar. The isentropic efficiencies of the turbine and the compressor are 90% and 85%, respectively. Air fuel ratio is 60:1. The calorific value of the fuel used is 42 MJ/kg and mass flow rate of air is 2 kg/s. Assume air as an ideal gas with specific heat at constant pressure equal to 1.005 kJ/kgK and the specific heat ratio as 1.4. Consider specific heat at constant pressure for fuel also as 1.005 kJ/kgK and specific heat ratio is 1.4. Find the following: 1). Heat supplied by fuel to the plant in kJ/s is a) 1300 b) 1400 c) 1000 d) 900 2). Work required to drive the Compressor in kW is a) 400 b) 309 c) 595 d) 658 3). Actual turbine outlet temperature in Kelvin is a) 672 b) 792 c) 710 d) 590 4). Thermal efficiency of the plant in percentage is a) 21 b) 29 c) 19 d) 39
I'm not sure where these equations are coming from, the summary sheet for this chapter of this specific book denote a completely different set of equations. Can anyone clarify? Specifically, where did he derive (T1/T2) = (P1/P2)^k-1/k. The only thing that's similar in the book is (T2/T1) = (P2/P1)^k-1/k....so, I see that relationships are inverted but normally this professor follows the book pretty closely and never goes rogue. Lastly, the pressure ratio equation is not listed at the end of the chapter as well....so, a little confused.
It is because, in the pump and compressor, the temperature of the fluid increases so the entropy also increases. On the other hand, in turbines, the pressure and the temperature drops, which results in a decrease of entropy!
@@brucewayne3227 It always increases as a whole but of a system can decrease. If what you are saying is true then all refrigerators and all other HVAC appliances are working on the alliens law
@@saqibirshad5126 Not sure I follow - Entropy is always increasing in an actual, real life cycle or system. If you can design a system with entropy decreasing, let me know.
In an open cycle gas turbine plant, air enters the compressor at 1 bar and 290 K. The pressure at the exit of compressor is 5 bar. The isentropic efficiencies of the turbine and the compressor are 90% and 85%, respectively. Air fuel ratio is 60:1. The calorific value of the fuel used is 42 MJ/kg and mass flow rate of air is 2 kg/s. Assume air as an ideal gas with specific heat at constant pressure equal to 1.005 kJ/kgK and the specific heat ratio as 1.4. Consider specific heat at constant pressure for fuel also as 1.005 kJ/kgK and specific heat ratio is 1.4. Find the following:
1). Heat supplied by fuel to the plant in kJ/s is
a) 1300
b) 1400
c) 1000
d) 900
2). Work required to drive the Compressor in kW is
a) 400
b) 309
c) 595
d) 658
3). Actual turbine outlet temperature in Kelvin is
a) 672
b) 792
c) 710
d) 590
4). Thermal efficiency of the plant in percentage is
a) 21
b) 29
c) 19
d) 39
thank you for helping me understand the steps to solve for isentropic efficiency.
Great lecture!
I'm not sure where these equations are coming from, the summary sheet for this chapter of this specific book denote a completely different set of equations. Can anyone clarify? Specifically, where did he derive (T1/T2) = (P1/P2)^k-1/k. The only thing that's similar in the book is (T2/T1) = (P2/P1)^k-1/k....so, I see that relationships are inverted but normally this professor follows the book pretty closely and never goes rogue. Lastly, the pressure ratio equation is not listed at the end of the chapter as well....so, a little confused.
In a previous video he wrote it as (T2/T1) = (P2/P1)^k-1/k so maybe it was an error this time?
@@scott337 Those two are same.
why the entropy rises in pump and compressor and drops in turbine
It is because, in the pump and compressor, the temperature of the fluid increases so the entropy also increases. On the other hand, in turbines, the pressure and the temperature drops, which results in a decrease of entropy!
@@tarashri769 i thought entropy doesn’t decrease. I thought it’s always increasing. Am i wrong?
@@brucewayne3227 It always increases as a whole but of a system can decrease. If what you are saying is true then all refrigerators and all other HVAC appliances are working on the alliens law
@@saqibirshad5126 Not sure I follow - Entropy is always increasing in an actual, real life cycle or system. If you can design a system with entropy decreasing, let me know.
anyone know which book contains the homework he assigns?
Cengel and Boles, "Thermodynamics: An Engineering Approach (8th edition)"