AE 3450

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AE 3450

• Thermodynamics and Compressible Flow

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Rules of the Game

• Prerequisites PHYS 2212
• Concept of conservation
• Programming
• Contact info 404-894-3060
• jeff.jagoda_at_ae.gatech.edu
• M. K. Room 320
• www.ae.gatech.edu/jjagoda/

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Rules of the Game

• Questions during class
• after class
• via e-mail
• swing by my office
• Homework prepared individually
• graded
• solutions posted
• no late hand-ins

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Rules of the Game

• Grading
• Homework 15
• 2 Quizes 18 each
• Computer project 15
• Final 34
• Class attendance ..
• GT Honor Code applies.

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Texts

• Gas Dynamics, James John
• Prentice-Hall
• Thermodynamics, Black Hartley
• Harper Collins

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Introduction and Overview

• Thermodynamics
• The study of energy and its relationship to the
  properties of matter.
• How do properties of matter (p, T, ?) change
  when others are modified ?
• Apply to devices that use energy
• Engines Compressors Pumps
• Nozzles Heat pumps Fuel cells
• Determine efficiencies

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Laws of Thermodynamics

• Thermodynamics is based on basic laws derived
  from empirical observations
• First Law - Conservation of energy.
• Energy can be neither created or destroyed.
• Different types of energy (potential kinetic)
  sum to a constant value if isolated.
• Otherwise, energy is transferred as heat or
  work.

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Laws of Thermodynamics

• Second Law introducing entropy
• Tells us which processes are possible
• (entropy must be conserved or increase,
• entropy cannot be destroyed)
• Tells us which way processes can proceed or
  which way it will proceed if left alone
• (e.g., chemical equilibrium, motion with
  friction, heat transfer etc.)

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Control Volume Analysis

• Many engineering problems, especially in
  aerospace engineering deal with flows. To keep
  track of these fluids need a boundary. We then
  keep track of the fluid entering the control
  volume through the control surface.
• Proper choice of control surface makes life
  easier.

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Compressible Flow

• Density changes because of changes in velocity
  (occurs if M gt0.3).
• As a result there is an additional variable that
  changes.
• This creates unexpected results such as the
  acceleration of supersonic flows in an expanding
  duct.
• Mach is ratio between inertial forces and
  compressibility.

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Compressible Flow

• Use of shocks by nature to tie together seemingly
  incompatible flow regimes.
• Study effects of friction on high speed flows.
• Study effect of heating/cooling on high speed
  flows.

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Units

• Get in the habit of including units in all
  calculations.
• You will loose credit if you do not.
• Review units in Black Hartley Sections 1.3-1.5
• Homework 1.4, 1.5, 1.12, 1.35, 1.36