MEC  511:    

Thermodynamics  and  Fluids  

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Compulsory   Text   2:     Fundamentals   of   Engineering   Thermodynamics,   7th   Edition;   M.   J.  Moran,  H.  N.  Shapiro,  D.  D.  Boettner  and  M.  B.  Bailey;  Wiley,  2011.  (Sold  as  a  custom  ebook  covering   chapters   1-­‐5.   Students   may   purchase   an   access   code   through   the   Ryerson  Bookstore  and  then  download  a  PDF  file).  

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Course  Content    

Chapters   Sections   Hours   Thermodynamics-­‐Topic,  Description  

1 1.1-1.7 3 Introduction: Open, closed, isolated systems; property, state, and process; extensive and intensive properties; SI and US systems of units; pressure units; temperature measurement and units.

2 2.1-2.6 3 First Law of Thermodynamics: Work, kinetic, and potential energy; conservation of energy; power, evaluating work, polytropic processes; energy balance; processes for closed systems; energy analysis of cycles; power, refrigeration, and heat pump cycles.

3 3.1-3.6, 3.8.1

3 Evaluating Properties - Vapours: Steam tables and properties; saturation tables; superheat tables.

3 3.9-10, 3.12-13.1, 3.14.2, 3.15

3 Evaluating Properties – Gases: Ideal gas law; internal energy, enthalpy, and specific heats; ideal gas law and constant specific heats; polytropic gas processes.

4 4.1-4.10 4 Control Volume Analysis Using Energy: conservation of mass; conservation of energy; analyzing control volumes at steady state.

5 5.1-10 3 Second Law of Thermodynamics: Reversible and irreversible processes; internally reversible process; Second law and thermodynamic cycles; power cycle, refrigeration and heat pump applications; Carnot cycle for vapours and gases.

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Laboratory  Sessions  

Lab Title Room

1 Measurement of Dynamic Viscosity. KHE-31

2 The Venturi Flow Meter. KHE-31

3 Steam Pressure/Temperature Relationship. KHE27-29

4 Steam Quality Measurement. KHE27-29

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Chapter  1:  Introductory  Concepts  and  Definitions      

1.1  Using  Thermodynamics    

1.2  Defining  Systems    

1.3  Describing  Systems  and  Their  Behavior    

1.4  Measuring  Mass,  Length,  Time,  and  Force    

1.5  Two  Measurable  Properties:  Specific  Volume  and  Pressure    

1.6  Measuring  Temperature    

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1.1  Using  Thermodynamics    

The  word  thermodynamics  comes  from  the  Greek  words  Therme  (heat)  and  dynamis  (force)  .    The  formal  study  of    Thermodynamics  began  in  the  early  nineteenth    century  through  consideration  of  motive    power  of  heat.  

Thermodynamics  in    

Physics  

Engineering  Science  

Properties  of  matter  

Interaction  of  systems  and  their    environment  

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Engineers   to  achieve  improved  designs  and  better  performance  

increase  in  the  output  of  some  desired  product  

 a  reduced  input  of  a  scarce  resource  

a  reduction  in  total  costs  

a  lesser  environmental  impact  

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1.2  Defining  Systems      In  thermodynamics  the  term  system    is  used  to  identify  the  subject  of  the  analysis.  Once  the  system  is  defined  and  the  relevant  interactions  with  other  systems  are  identified,  one  or  more  physical  laws  or  relations  are  applied.  

 study  a  quantity  of  matter  contained  within  a  closed,  rigid-­‐walled  tank.  

considering  something  such  as  a  pipeline  through  which  natural  gas  flows.  

 Everything  external  to  the  system  is  considered  to  be  part  of  the  system’s  surroundings.    The  system  is  distinguished  from  its  surroundings  by  a  specified  boundary,    which  may  be  at  rest  or  in  motion.  

Examples    

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Type  of  Systems    

Closed  Systems       Control  Volumes  

 fixed  quantity  of  matter    control  volume  is  a  region  of  space  through  which  mass  may  flow  

isolated  system  

 does  not  interact  in  any  way  with  its  surroundings  

 The  term  control  mass    is  sometimes  used  in  place  of  closed  system,  and  the      term  open  system    is  used  interchangeably  with  control  volume.      When  the  terms  control  mass  and  control  volume  are  used,  the  system    boundary  is  often  referred  to  as  a  control  surface  .  

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1.3  Describing  Systems  and  Their  Behavior    

MACROSCOPIC  AND  MICROSCOPIC  VIEWS  OF  THERMODYNAMICS  

 applications  :    lasers,  plasmas,  high-­‐speed  gas  flows,  chemical  kinetics,  very  low  temperatures  (cryogenics).  

macroscopic  approach     gross  or    overall  behavior  

microscopic  approach    statistical    thermodynamics  

structure  of  matter  

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PROPERTY,  STATE,  AND  PROCESS  

   

 The  word  state    refers  to  the  condition  of  a  system  as  described  by  its  properties.  

 A  process  is  a  transformation  from  one  state  to  another.  

 A  system  is  said  to  be  at  steady  state    if  none  of  its  properties  changes  with  time.  

 property     macroscopic  characteristic  of  a  system  

mass,  volume,  energy,  pressure,  and  temperature    

is  a  sequence  of  processes  that  begins  and  ends  at  the  same  state.    At  the  conclusion  of  a  cycle  all  properties  have  the  same  values    they  had  at  the  beginning.  

thermodynamic  cycle    

For  example,  steam  circulating  through  an  electrical  power  plant  executes  a  cycle.  

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 A  quantity  is  a  property  if  its  change  in  value  between  two  states  is  independent  of  the  process.  

EXTENSIVE  AND  INTENSIVE  PROPERTIES  

Examples  are    Mass,  volume,  energy.  

extensive     its  value  for  an  overall  system  is  the  sum  of  its  values  for  the  parts  into  which  the  system  is  divided.  

Intensive     Their  values  are  independent  of  the  size  or  extent  of  a  system  and  may  vary  from  place  to  place  within  the  system  at  any  moment.    

Specific  volume,  pressure,  and  temperature  

PHASE  AND  PURE  SUBSTANCE  

 phase     a  quantity  of  matter  that  is  homogeneous  throughout  in  both  chemical  composition  and  physical  structure.  

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Homogeneity  in  physical  structure  means  that  the  matter  is  all  solid,    or  all  liquid,    or  all  vapor    (or  equivalently  all  gas  ).    

A  system  can  contain  one  or  more  phases.    

For  example,  a  system  of  liquid  water  and  water  vapor  (steam)  contains  two    phases.  

For  example,  if  liquid  water  and  water  vapor  form  a  system  with  two  phases,  the  system  can  be  regarded  as  a  pure  substance  because  each  phase  has  the  same  composition.  

pure  substance     is  one  that  is  uniform  and  invariable  in  chemical  composition.    

Equilibrium  

 balance  of  forces      balance  of  other  influences.    mechanical,  thermal,  phase,  and  chemical  

equilibrium.  

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1.5  Two  Measurable  Properties:  Specific  Volume  and  Pressure    

Specific  volume  

ρ = lim (mV)

V→ "VDensity  for  a    continuum  

 where  V  ’    is  the  smallest  volume  for  which  a  definite  value  of  the  ratio  exists.  

m = ρ dVV∫

 The  specific  volume            is  defined  as  the  reciprocal  of  the  density  

v = 1ρ

m3

kg!

"#

$

%&

v

This  is  the  specific  volume  on  mass  basis  

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 specific  volume  on  a  molar  basis  in  terms  of    kmol(kilomole)  

n = mM

n,  the  number  of  kilomoles  of  a  substance  m,  mass  in  kg  M,  molecular  weight  in  kg/kmol  

 To  signal  that  a  property  is  on  a  molar  basis,  a  bar  is  used  over  its  symbol.  Thus,              signifies  the  volume  per  kmol.  The  units  used  for                  are  m3  /kmol.  

vv

v =M v

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Pressure  

p = lim (FnormalA

)A→ "A

1 pascal =1N m2

1kpa =103 N m2

1bar =105 N m2

1Mpa=106 N m2

1  standard  atmosphere  (  1  atm)=    1.01325×105 N m2

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1.6  Measuring  Temperature    

To  measure  and  to  quantify  the  hotness  and  coolness  of  body  we    use  thermometers  and  temperature  scale.        

1.6.1  Thermal  Equilibrium  When  two  systems  with  different  temperatures  reaches  a  condition  in    which  there  is    no  thermal  interaction  between  them  then  we  have    Thermal  equilibrium  

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When  a  system  undergoes  a  process  while  it  enclosed  by  an  adiabatic  wall,  it    experiences  no  thermal  interaction  with  its  surrounding.  This  process  called    adiabatic  process.    

 A  process  that  occurs  at  constant  temperature  is  an  isothermal  process.  

zeroth  law  of  thermodynamics  when  two  bodies  are  in  thermal  equilibrium    with  a  third  body,  they  are  in  thermal  equilibrium  with  one  another.      

 Thermometers    Any  body  with  at  least  one  measurable  property  that  changes  as  its  temperature  changes  can  be  used  as  a  thermometer.  Such  a  property  is  called  a  thermometric  property.  

 liquid-­‐in-­‐glass  thermometer    thermocouples  

 Kelvin  Scale  

 Celsius  Scale  T oC( ) = T K( )− 273.15

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END  OF  CHAPTER      1