CHEMATE 151 THERMODYNAMICS

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CHE/MATE 151- THERMODYNAMICS

• CONCEPTS TERMINOLOGY

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FUNDAMENTALS

• UNITS - CRITICAL FACTOR IN ALL CALCULATIONS
• BASIC ARE SI
• NEED CAPABILITIES IN ENGLISH, CGS AND MKS
• PRIMARY VARIABLES
• TEMPERATURE
• PRESSURE
• VOLUME
• MASS
• DERIVED VARIABLES ALL OTHERS
• WORK/ENERGY

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UNIT CONVERSION
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TYPICAL UNIT PREFIXES
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FORMS OF ENERGY

• QUANTITY FOR SYSTEM
• UNITS BTU, JOULES, ft-lbf, Nm
• SPECIFIC ENERGY
• QUANTITY PER UNIT
• UNITS BTU/lb, kJ/kg, J/kg-mole
• RATE
• POWER
• UNITS BTU/HR, JOULE/SEC, WATT, HP

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COMPONENTS IN ENERGY BALANCES

• KINETIC ENERGY
• BASED ON MOMENTUM OF FLUID RELATIVE TO ZERO
  VELOCITY
• POTENTIAL ENERGY
• POTENTIAL ENERGY - BASED ON RELATIVE POSITION

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FORCE CONCEPTS

• UNITS
• NEWTON
• NEWTONS SECOND LAW OF MOTION

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PROPORTIONALITY CONSTANT gc

• gc IS A PROPORTIONALITY CONSTANT
• FOR SI UNITS
• FOR ENGLISH UNITS

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TYPES OF PROCESSES

• STATIC - NO CHANGE IN THE SYSTEM
• TRANSIENT - CHANGE OF FLOWS OF ENERGY OR MASS IN
  THE SYSTEM
• STEADY-STATE - CONSTANT FLOWS OF ENERGY MASS
  WITH CONSTANT SYSTEM PROPERTIES.
• AUTOMOBILE ENGINE ON LEVEL ROAD, WITH CONSTANT
  VELOCITY AND CONSTANT EXTERNAL CONDITIONS.
• MANUFACTURING PROCESS WITH CONSTANT RATES OF
  OPERATION

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FUNDAMENTAL FLUID DYNAMIC CONCEPTS

• STREAMLINES
• FOLLOW PATHS OF NEARLY CONSTANT AXIAL
• NO RADIAL VELOCITY.
• THREE DIMENSIONAL, BUT THE SYSTEM CAN BE
  SIMPLIFIED USING SYMMETRY.
• VELOCITY GRADIENT
• CAN BE DETERMINED BY MOVING NORMAL TO
  STREAMLINES.
• TYPICALLY RANGING FROM ZERO AT CONSTRAINING
  SURFACE TO SOME MAXIMUM VALUE.

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RESULT OF APPLICATION OF FORCE TO A SOLID

• FORCE APPLIED TO AN ELASTIC SOLID
• STRESS (PRESSURE/AREA) RESULTS IN A STRAIN
  (ELONGATION)
• IF THE SYSTEM FOLLOWS HOOKE'S LAW, THEN THE RATIO
  IS YOUNG'S MODULUS

http//www.grantadesign.com/education/sciencenote.
htm
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RESULT OF APPLICATION OF FORCE TO A FLUID

• OCCURS WHEN A FLUID IS SITS BETWEEN A MOVING AND
  STATIONARY PLATE.
• LOWER PLATE WITH AREA "A" IS ACCELERATED WITH
  FORCE "F" TO VELOCITY V.
• AT STEADY-STATE, VELOCITY GRADIENT IS LINEAR IF
  SYSTEM FOLLOWS NEWTON'S LAW OF VISCOSITY.

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NEWTONS LAW OF VISCOSITY

• µ IS THE DYNAMIC VISCOSITY COEFFICIENT TO RELATE
  STRESS AND STRAIN

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FLUID FLOW COMPLICATIONS

• COMPRESSIBLE NON-COMPRESSIBLE FLOW
• TRANSIENT CONDITIONS
• NON-NEWTONIAN FLUIDS
• FLOW REGIMES - LAMINAR, TURBULENT AND TRANSITION

http//www.cfdrc.com/bizareas/aerospace/propulsion
/sim_analysis.html
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MODES OF HEAT TRANSFER

• CONDUCTION - FLUX THROUGH A SOLID
• CONVECTION FLUX THROUGH A FLUID
• RADIATION FLUX FROM A SURFACE

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JOULES EXPERIMENTS

• RELATED WORK AND HEAT
• BOTH ARE FORMS OF ENERGY

http//www.lightandmatter.com/html_books/0sn/ch02/
ch02.html
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INTERNAL ENERGY

• REPRESENTS THE THERMAL CAPACITANCE OF A COMPONENT
• DOES NOT HAVE ABSOLUTE VALUES
• INTERNAL ENERGY VARIABLES ARE
• U INTERNAL ENERGY
• H ENTHALPY
• G GIBBS FREE ENERGY
• A HELMHOLTZ FREE ENERGY

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INTERNAL ENERGY FIRST LAW CONSERVATION OF
ENERGY
http//www.grc.nasa.gov/WWW/K-12/airplane/thermo1.
html
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VARIATION IN INTERNAL ENERGY

• BY PHASE AND ATOMIC STRUCTURE
• BY CHEMICAL PROPERTIES

http//hyperphysics.phy-astr.gsu.edu/hbase/thermo/
inteng.html
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FIRST LAW

• ENERGY IS CONSERVED
• IT IS NOT CREATED OR DESTROYED
• IT TAKES VARIOUS FORMS DUE TO PROCESSING
• YOU CANNOT WIN, YOU CAN ONLY BREAK EVEN.
• CHANGE IN INTERNAL ENERGY HEAT INTO SYSTEM
  WORK DONE TO THE SYSTEM