Thermodynamics filled in class notes_Part_18

# Thermodynamics filled in class notes_Part_18 - 2.5. BRAYTON...

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Unformatted text preview: 2.5. BRAYTON 43 Now state three has T 3 = 1400 K . Recall that 2 → 3 involves heat addition in a combustion chamber. Now calculate T 4 s for the ideal turbine. Recall that the expansion is to the same pressure as the compressor inlet so that P 3 /P 4 = 10. The isentropic relations give parenleftbigg T 4 s T 3 parenrightbigg k/ ( k − 1) = P 4 P 3 , (2.226) T 4 s = T 3 parenleftbigg P 4 P 3 parenrightbigg ( k − 1) /k , (2.227) = (1400 K ) parenleftbigg 1 10 parenrightbigg (1 . 4 − 1) / 1 . 4 , (2.228) = 725 . 126 K. (2.229) Now account for the actual behavior in the turbine: η t = T 3 − T 4 T 3 − T 4 s , (2.230) T 4 = T 3 − η t ( T 3 − T 4 s ) , (2.231) = (1400 K ) − (0 . 8)((1400 K ) − (725 . 126 K )) , (2.232) = 860 . 101 K. (2.233) Now calculate the thermal efficiency of the actual cycle. η = w net q H = q H − q L q H = 1 − q L q H = 1 − c P ( T 4 − T 1 ) c P ( T 3 − T 2 ) = 1 − T 4 − T 1 T 3 − T 2 , (2.234) = 1 − 860 . 101 K − 300 K 1400 K −...
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## This note was uploaded on 11/26/2011 for the course EGN 3381 taught by Professor Park-sou during the Fall '11 term at FSU.

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Thermodynamics filled in class notes_Part_18 - 2.5. BRAYTON...

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