Chapter 1 Gas Power Cycle

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Gas cycles VS Vapor cycles (cont’d) Vapor cycles : Working fluid exists in the vapor phase during on part of the cycle and in the liquid phase during another part such as in steam power plant cycle and refrigeration cycles The Carnot Cycle and Its Value in Engineering Heat Engine Source, T H Sink, T L Q H Q L W net The 4 processes of the carnot cycle: (Heat Engine) � Reversible Isothermal heat transfer from high temp. reservoir. � Reversible adiabatic expansion. � Reversible Isothermal heat transfer to low temp. reservoir � Reversible adiabatic compression
Example 8.1 Show that the thermal efficiency of a Carnot cycle operating between the temperature limits of T L AND T H is solely a function of these two temperatures. Solution from Wnet QL ηth = = 1− QH QH TH 1 2⎛ δQ ⎞ and S2 − S1 = ∫ ⎜ ⎟ 1 ⎝ T ⎠rev for rev. Isothermal process, T = const. TL 4 1 2 1Q2 then S2 − S1 = Q T ∫ δ = 1 rev T or 1Q2 = T ( S2 − S1) Therefore, QH = TH ( S2 − S1), and QL = TL ( S3 − S4 ) But S1 = S4, and S2 = S3 QL TL ( S3 − S4 ) TL ηth = 1− = 1− = 1− Q T ( S − S ) T H H Actual Gas Cycle 2 1 H T Q H Q L s 1 =s 4 s2 =s 3 � Open Cycle (intake, discharge) � Working fluid is not a pure substance � Heat input by COMBUSTION of a fuel � Involve friction Source: Assoc.Prof.Dr.Sommai Prepream Exhaust gas 2 3 s Fuel + air mixture
Page 1: Chapter 1 Gas Power Cycle Content:
Page 5 and 6: P Mean Effective Pressure, MEP Conc
Page 7 and 8: P Air Standard Otto Cycle Ideal Ott
Page 9 and 10: Example 8.2 An ideal Otto cycle has
Page 11 and 12: 1st law : closed system Ideal gas:
Page 13 and 14: Ideal Brayton Cycle Brayton Cycle c

Chapter 1 Gas Power Cycle

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