Thermodynamics filled in class notes_Part_25

Thermodynamics filled in class notes_Part_25 - 2.7 OTTO 57...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

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

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

Unformatted text preview: 2.7. OTTO 57 The thermal efficiency is found as follows: η = w net q H , (2.354) = q H − q L q H , (2.355) = 1 − q L q H , (2.356) = 1 − c v ( T 4 − T 1 ) c v ( T 3 − T 2 ) , (2.357) = 1 − T 4 − T 1 T 3 − T 2 , (2.358) = 1 − T 1 parenleftBig T 4 T 1 − 1 parenrightBig T 2 parenleftBig T 3 T 2 − 1 parenrightBig . (2.359) Now one also has the isentropic relations: T 2 T 1 = parenleftbigg V 1 V 2 parenrightbigg k − 1 , (2.360) T 3 T 4 = parenleftbigg V 4 V 3 parenrightbigg k − 1 . (2.361) But V 4 = V 1 and V 2 = V 3 , so T 3 T 4 = parenleftbigg V 1 V 2 parenrightbigg k − 1 = T 2 T 1 . (2.362) Cross multiplying the temperatures, one finds T 3 T 2 = T 4 T 1 . (2.363) Thus the thermal efficiency reduces to η = 1 − T 1 T 2 . (2.364) In terms of the compression ratio r v = V 1 V 2 , one has η = 1 − r 1 − k v = 1 − 1 r k − 1 v . (2.365) Note if the compression ratio increases, the thermal efficiency increases. High compression ratios introduce detonation in the fuel air mixture. This induces strong pressure waves inratios introduce detonation in the fuel air mixture....
View Full Document

{[ snackBarMessage ]}

Page1 / 2

Thermodynamics filled in class notes_Part_25 - 2.7 OTTO 57...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online