Process

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Process Cycles

• P M V Subbarao
• Professor
• Mechanical Engineering Department
• I I T Delhi

Mathematical Models for Happening
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Thermodynamic Process

• The path of succession of states through which
  the system passes is called the process.
• Quasi-equilibrium process is a collection of
  changes, in which the deviation from
  thermodynamic equilibrium is infinitesimal.
• All the states the system passes through during a
  quasi-equilibrium process may be considered as
  equilibrium states.

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Development of Low Emission Diesel Engine
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Description of Happening in an Engine Cylinder
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Selection of Instrument for Exact Capture of A
Happening to A System
The characteristic equation of nth order
Pressure Gauge
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Laplace Transformations for Instruments
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Diagnosis of The Happening for Better Emissions
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Process Executed by A Control Volume
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Change of State in A Control Volume
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Thermodynamic Process

• During a quasi-equilibrium or quasi-static
  process, the system remains practically in
  equilibrium at all times.
• Quasi-equilibrium work-producing devices deliver
  the maximum work.
• Theoretical description of processes is possible
  by keeping any one thermodynamic property may be
  held constant.
• Process Property
• isobaric pressure
• isothermal temperature
• isochoric volume
• Adiabatic No Heat Transfer

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Representation of Thermodynamic Processes
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Thermodynamic Cycle

• A process (series of connected processes) with
  identical end states.
• When a system in a given initial state goes
  through a number of different changes of state or
  processes and finally returns to its initial
  state, the system has undergone a cycle.
• At the conclusion of a cycle, all the properties
  have the same value they had at the beginning.

Cyclic Working of Left Ventrical
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Energy Cycles in Nature

• The sun is the source of all that happens on our
  earth.
• Every form of energy, except for atomic energy,
  can be traced back to the sun.
• The earth is at the best possible distance from
  the sun for the sun's heat to provide many
  systems on earth.
• These systems are atmosphere, hydrosphere,
  Biosphere etc.
• Energy from sunlight is used by these systems to
  created many natural cycles.
• This energy is continuously converted/transferred
  during these cycles.

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Various Cycles of Nature

• Water Cycle
• Wind Cycle
• Life Cycles of Animals
• Life Cycles of Plants
• Seasonal Cycles
• Planetary Cycles
• Rock Cycles
• Geo-Physical Cycles
• Chemical Cycles
• Disease Cycles

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Water Cycle

• All of the water that is on the earth has always
  been here.
• Earth never gets water added to it--nor does
  water disappear from the earth.
• Water is constantly recycled in a process known
  as the hydrologic or water cycle.
• Why?
• Only 3 is fresh water.
• About 1/2 of 1 of the water on earth is
  groundwater.
• Only about 1/100 of 1 of the water on earth is
  in the rivers and lakes.
• Water is essential to life on earth, so it is
  important to have continuous occurrence of water
  cycle

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Hydrological Cycle
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Seasonal Variation of Kinetic Energy of Wind
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Rock Cycle
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Energy Interaction in Rock Cycle
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Rock Cycles

• Rocks are continually circulating in the mantle
  just below the crust of the earth.
• They are sometimes thrust up into the crust due
  to convection currents.
• Rocks can also reach the surface when they are
  spit out by volcanoes.
• Once on the surface of the earth, rocks cool
  down.
• Over time, they are broken up or worn down by
  weather, and the fragments are carried back to
  the ocean by way of wind, rain, and the flow of
  rivers and streams.
• All of these small pieces of rock collect as
  sediment at the bottom of seas and oceans.
• The sediment solidifies into rock and is drawn
  back down in to the mantle at subduction zones or
  reaches the surface again as sea levels change or
  plates collide

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The Carbon Cycle
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CO2 Cycle
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Life Cycle an Ozone
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New Ozone Cycle
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Plastics that never exhaust the resources of the
earth
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Energy sources such as the fossil fuels of coal,
petroleum, and natural gas are really just
ancient stockpiles of the sun's energy stored in
plants and the animals that ate those plants that
are thousands or millions of years old.
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Engineering Cycles

• Carnot Cycle
• Lenoir Cycle
• Otto Cycle
• Sterling Cycle
• Atkinson Cycle
• Diesel Cycle
• Brayton cycle
• Rankine Cycle
• Vapour Compression Refrigeration Cycle
• Vapour Absorption Refrigeration Cycle

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The substance contained by the system undergoes a
thermodynamic process/cycle

• The potential of A Process/Cycle Depends on the
  substance used by (present in ) the system.

• How to begin the description of A Substance?
• Development of Equation of state
• Is it possible to develop a single EOS model for
  any substance?