Thermodynamics filled in class notes_Part_17

# Thermodynamics filled in class notes_Part_17 - 2.5. BRAYTON...

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Unformatted text preview: 2.5. BRAYTON 41 For the cycle, the first law holds that w net = q net = q H − q L . (2.201) One notes for an isobaric control volume combustor that dE cv dt bracehtipupleft bracehtipdownrightbracehtipdownleft bracehtipupright =0 = ˙ Q cv − ˙ W cv bracehtipupleftbracehtipdownrightbracehtipdownleftbracehtipupright =0 + ˙ mh in − ˙ mh out . (2.202) So ˙ Q cv = ˙ m ( h out − h in ) , (2.203) ˙ Q cv ˙ m = h out − h in , (2.204) q = h out − h in , (2.205) q = c P ( T out − T in ) . (2.206) So the thermal efficiency is 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 1 parenleftBig T 4 T 1 − 1 parenrightBig T 2 parenleftBig T 3 T 2 − 1 parenrightBig . (2.207) Now because of the definition of the process, one also has P 3 P 4 = P 2 P 1 . (2.208) And because 1 → 2 and 3 → 4 are isentropic, one has P 2 P 1 = parenleftbigg T 2 T 1 parenrightbigg k/ ( k − 1) = P 3 P 4 = parenleftbigg T 3 T 4 parenrightbigg 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_17 - 2.5. BRAYTON...

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