ME300Lecture41

# ME300Lecture41 - Lecture 41 Continue Brayton Cycle...

This preview shows pages 1–6. Sign up to view the full content.

41.1 Lecture 41: Continue Brayton Cycle Irreversibilities of Brayton cycles: Deviation of actual gas-turbine cycles from idealized ones: s 2s 1 C a 2a 1 a 3 4a T s 3 4s w h h w h h w h h w h h Note: T 2 > T 2s if p 2 = p 2s T 4 > T 4s if p 4 = p 4s irreversibilities change mechanical energy to thermal energy through friction.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
41.2 Continue Brayton Cycle Continue irreversibilities of Brayton cycles: Example: T 1 = 22 o C, p 1 = 0.95 bars, r p = p 2 /p 1 = 6, T 3 = 1100 K w C /w T Ideal 0.38 0.44 C = 0.82 and T = 0.85 0.23 0.62 Notes: » The overall efficiency is reduced by 40%! » Gas turbine performance is very sensitive to turbine and compressor efficiencies!
41.3 Continue Brayton Cycle Introduce “regeneration” to boost overall efficiency : » Idea: reclaim “waste” heat normally exhausted to ambient. Regenerative open Brayton cycle: 4 1 fuel q R air 3 5 2 x Exhaust gases Regenerative heat exchanger Combustor w net

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
41.4 Continue Brayton Cycle Continue regenerative Brayton cycle: s T 1 2 4 3 x 5 Reduction in q in Reduction in q out q in = q x 3 q out = q 5 1
41.5

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 18

ME300Lecture41 - Lecture 41 Continue Brayton Cycle...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online