Lecture 10

Question 1

What differentiates the entropy balance equation?

Answer 1

It is non-conservative

Question 2

What is a heat reservoir?

Answer 2

A source from which heat can be extracted without changing its temperature,

Question 3

What are the steps of carnot cycle?

Answer 3

1 - 2 : Isothermal expansion
2 - 3: Adiabatic Expansion
3 - 4: Isothermal Compression
4 - 1: Adiabatic Compression

Question 4

What are assumed constants for isothermal and isentropic changes of state?

Answer 4

c_p and c_v

Question 5

What is polytropic formulation of isentropic?

Answer 5

pv^\gamma = const

Question 6

What is polytropic formulation of isothermal?

Answer 6

pv^1 = const

Question 7

What is polytropic formulation of isochoric?

Answer 7

pv^\infty = const

Question 8

What is polytropic formulation of isobaric?

Answer 8

pv^0 = const

Question 9

Is isochoric or isobaric process steeper and why?

Answer 9

Isochoric because c_v < c_p

Question 10

What is enthalpy in in T-s diagram

Answer 10

Total area under box + in bos

Question 11

What is Q out in T-s diagram?

Answer 11

Area under box

Question 12

What is work in t-s diagram?

Answer 12

Area inside box

Question 13

Do T-s Diagrams work well for real fluids?

Answer 13

No

Question 14

What are the steps in the brayton cycle?

Answer 14

1-2: Adiabatic compression
2-3: Isobaric heat in
3-4: Adiabatic expansion
4-1: Isobaric heat out

Question 15

What is net work in brayton cycle?

Answer 15

turbine work + compressor work

Question 16

What is compressor work in brayton cycle?

Answer 16

h_2 - h_1

Question 17

What is turbine work in brayton cycle?

Answer 17

h_4 - h_3

Question 18

When can you read work and heat values from h-s diagram

Answer 18

When they depend only on enthalpy change