chap 8 - CHAPTER Entropy 8.1 The Inequality of Clausius...

Info iconThis preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon
CHAPTER Entropy
Background image of page 1

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

View Full DocumentRight Arrow Icon
8.1 The Inequality of Clausius
Background image of page 2
Review Ch. 7 7.6 Two Propositions on Carnot Engine Also called Carnot Principles 1. The efficiency of an irreversible heat engine is always less than that of a reversible one operating between the same two reservoirs. 2.The efficiencies of all reversible engines are the same when operating between the same two reservoirs. ,R e , HL Th v Th Irr Same T and T
Background image of page 3

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

View Full DocumentRight Arrow Icon
Re () , mod LL v HH For a reversible process only QT K K Ther ynamic Temperature Scale 7.9 Thermodynamic Temperature Scale
Background image of page 4
Thermal Efficiency : the fraction of the heat input that is converted to net work output is a measure of the performance of a heat engine  , Re ,max , , Net work ouput Thermal efficiency= Total heat input () 1, ( ) , mod 1 Net out th in LL L th v HH H th th Carnot L H W Q QQ T K T K Ther ynamic Temperature Scale Tk = First Law Efficiency 7.10 The Carnot Heat Engine Carnot Efficiency
Background image of page 5

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

View Full DocumentRight Arrow Icon
The Clausius Inequality For all cyclic processes, Clausius Inequality states : The Clausius Inequality reduces to the Clausius Equality when the system executes a reversible cycle. 0 cycle Q T 0R e 0 Q v T Q Irr T
Background image of page 6
Schematic of a steam power plant Typical Heat Engine 2341 1234 24 13 cycle Q QQQQ T TTTT QQ TT       1 2 3 4 0 0
Background image of page 7

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

View Full DocumentRight Arrow Icon
24 13 cycle HL QQ Q TT T      Re ,Re () , LL v HH Hv Lv For a reversible process only QT K K 0 L v v Q T   
Background image of page 8
24 13 cycle HL QQ Q TT T      ,R e , , , , 11 Th v Th Irr Lv L I r r Hv L I r r L I r r Since More efficient engine rejects less heat The cycle is irreversible if any part is irreversible
Background image of page 9

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

View Full DocumentRight Arrow Icon
,R e , Lv L I r r Since QQ , H vL I r r HL TT  24 13 , 0 cycle Irr Hv L I r r Q T        For an irreversible cyclic process In General, 1,. . 00 sin i in i Q Q for finite number of heat sources or heat ks 
Background image of page 10
1,. . 00 sin i in i cycle Q Q for finite number TT of heat sources or heat ks  It is noted that the above Clausius Inequality was proved using a heat engine, but it can be proved that it is equally valid for a refrigeration system or a heat pump.
Background image of page 11

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

View Full DocumentRight Arrow Icon
Important Conclusion ,R e , ,, R e R e Th v Th Irr net out v net out Irr Hv v Since WW QQ Reversible engine generates maximum amount of work Under the same T H and T L .
Background image of page 12
For a Refrigeration System and Heat Pump ,, R e net in v net in Irr WW Reversible refrigeration system or heat pump requires minimum amount of work Under the same T H and T L .
Background image of page 13

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

View Full DocumentRight Arrow Icon
Image of page 14
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 39

chap 8 - CHAPTER Entropy 8.1 The Inequality of Clausius...

This preview shows document pages 1 - 14. Sign up to view the full document.

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