Keith D.

• Isothermal


  Process where the change in Internal Energy is equal to 0
• Otto Cycle


  Ideal Prototype of the spark – ignition engines, constant volume combustion
• Thermodynamics


  Branch of the physical sciences that treats of various phenomena of energy and the related properties of matter, especially of the laws of transformations of heat into other forms of energy and vice versa
• Density


  Mass per unit volume of a substance
• Polytropic process


  PVn = C
• Constant volume process


  Work done is zero
• Isothermal Process


  Pressure is inversely proportional to the Volume
• Isentropic Process


  S = C, Q = 0, ∆S = 0
• Isobaric Process


  PV diagram is represented by a horizontal line
• Isometric Process


  Non – flow work is equal to 0
• Adiabatic Process


  No heat added or subtracted from the air
• Isentropic Process


  Change in Enthalpy is equal to 0
• Isothermal Process


  Heat is equal to -∫VdP
• Brayton Cycle


  Cycle that a turbojet engine operates on
• Steady flow work


  Equal to -∫VdP if the change in kinetic energy is zero
• Isentropic Process


  Also known as a reversible adiabatic process
• Gas constant for air

  287.08 J/kg K
• Absolute pressure


  Vacuum pressure + standard atmospheric pressure
• Heat flow


  From high temperature to low temperature
• First Law of Thermodynamics

  Energy is neither created nor destroyed
• Enthalpy


  Sum of Internal Energy and Flow Work
• Barometer


  Measures Atmospheric Pressure
• Entropy


  Thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system
• Constant volume system


  Heat = Internal Energy
• Constant pressure system


  Heat = Enthalpy
• Endothermic Process


  Heat is being added to the system
• Work


  Unit is kg m^2/s^2
• Specific volume


  Inverse of density
• Potential Energy


  Depends on elevation
• Internal Energy


  Sum of Potential and Kinetic Energy of the molecules
• Newton's Second Law of Motion

  Force is directly proportional to the product of mass and acceleration
• Sign of heat


  Negative if heat is carried away from the system
• Sign of work


  Positive if work is done by the system
• Charles' Law


  If pressure is held constant, volume varies directly with absolute temperature
• Work done by the system

  Change in internal energy = work done
• Horsepower


  1 hp = 746 W
• Diesel Cycle


  • Isentropic Compression Ratio
  • Cutoff ratio
  • Pressure Ratio at constant volume addition of heat
• Thermal Efficiency


  Fraction of heat supplied to a thermodynamic cycle that is converted into work
• Indicated Horsepower


  Total power actually developed in an engine's cylinder without reference to friction losses
• Carnot Cycle


  Most efficient cycle conceivable