Thermal engineering om

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basics of thermodynamics, laws of thermodynamics, power plants

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Thermal engineering om

  1. 1. THERMAL ENGINEERING A. THERMODYNAMICES PROF . SHEKHAR S. BABAR MECHANICAL ENGINEERING DEPARTMENT ICEM
  2. 2. THERMODYNAMICES THERMO--- Heat Released DYNAMICS ----- Mechanical Action For doing work  The study of the effects of work, heat flow, and energy on a system  Movement of thermal energy  Engineers use thermodynamics in systems ranging from nuclear power plants to electrical components.  Thermodynamics is the study of the effects of work, heat, and energy on a system  Thermodynamics is only concerned with macroscopic (large- scale) changes and observations
  3. 3. SYSTEM, SURROUNDING ,UNIVERSE  SYSTEM-Area under thermodynamic study  SURROUNDING – Area outside the system  BOUNDARY- System & Surrounding are separated by some Imaginary Or real Surface/Layer/Partition  UNIVERSE – System & Surroundings put together is called Universe
  4. 4. 4 ISOLATED, CLOSED AND OPEN SYSTEMS Isolated System Neither energy nor mass can be exchanged. E.g. Thermo flask Closed System Energy, but not mass can be exchanged. E.g. Cylinder filled with gas & piston Open System Both energy and mass can be exchanged. E.g. Gas turbine, I.C. Engine
  5. 5. THERMODYNAMIC PROPERTIES  Thermodynamic Properties – It is measurable & Observable characteristics of the system.  Extensive: Depend on mass/size of system (Volume [V]), Energy  Intensive: Independent of system mass/size (Pressure [P], Temperature [T])  Specific: Extensive/mass (Specific Volume [v])
  6. 6. PRESSURE  P = Force/Area  Pa, Kpa,Bar, N/m2  Types:  Absolute  Gage (Vacuum)  Atmospheric  Pabs =Patm +/- Pgauge PRESSURE PRESSURE
  7. 7. Volume  Three dimensional space occupied by an object Unit- M3 , Liter 1 m3 = 103 lit Volume Volume
  8. 8. Temperature  Quantitative indication of Degree of Hotness & coldness of the body.  Unit- 0C , K , F  Thermometer  Thermometry Temperature Temperature Scale
  9. 9. Internal energy  Internal energy (also called thermal energy) is the energy an object or substance is due to the kinetic and potential energies associated with the random motions of all the particles that make it up.  Internal energy is defined as the energy associated with the random, disordered motion of molecules.  Unit- KJ , Joule Internal Energy Internal Energy [U]
  10. 10. Enthalpy  Total Heat content of Body  Heat supplied to the body Enthalpy increases & decreases when heat is removed  Enthalpy is a measure of the total energy of a thermodynamic system. Enthalpy Enthalpy
  11. 11. Work  Work = Force x Displacement (Nm) ( Joule)  Energy in Transient  Path function  High grade energy  Work done by the system on the surrounding -Positive work Work done on the system by surrounding – Negative work
  12. 12. HEAT  Energy transfer by virtue of temperature difference  Transient form of energy  Path function  Low grade energy  Negative heat- heat transferred from the system ( heat rejection)  Positive heat – heat transferred from surrounding to system (heat absorption)
  13. 13. HEAT  Energy transfer by virtue of temperature difference  Transient form of energy  Path function  Low grade energy  Negative heat- heat transferred from the system ( heat rejection)  Positive heat – heat transferred from surrounding to system (heat absorption) HEAT CONCEPT hot coldheat 26°C 26°C
  14. 14. Work & Heat  Work is the energy transferred between a system and environment when a net force acts on the system over a distance.  The sign of the work  Work is positive when the force is in the direction of motion  Work is negative when the force is opposite to the motion WORK WORK
  15. 15. LAWS OF THERMODYNAMICS  FIRST LAW OF THERMODYNAMICS (LAW OF ENERGY CONSERVATION)  SECOND LAW OF THERMODYNAMICS  ZEROTH LAW OF THERMODYNAMICS
  16. 16. Zeroth law of thermodynamics
  17. 17. FIRST LAW OF THERMODYNAMICS  CONSERVATION OF ENERGY  ALGEBRAIC SUM OF WORK DELIVERED BY SYSTEM DIRECTLY PROPOTOPNAL TO ALGEBRAIC SUM OF HEAT TAKEN FROM SURROUNDING  HEAT & WORK ARE MUTUALLY CONVERTIBLE  NO MACHINE CAPABLE OF PRODUCING WORK WITHOUT EXPENDITURE OF ENERGY  TOTAL ENERGY OF UNIVERSE IS CONSTANT
  18. 18. LIMITATIONS OF FIRST LAW OF THERMODYNAMICS  Can’t give the direction of proceed can proceed- transfer of heat from hot body to cold body  All processes involved conversion of heat into work & vice versa not equivalent.  Amount heat converted into work & vice versa  Insufficient condition for process to occurs
  19. 19. HEAT RESERVOIR, HEAT SOURCE, HEAT SINK  HEAT RESERVOIR- Source of infinite heat energy & finite amount of heat addition & heat rejection from it will not change its temperature  E. g. Ocean, River, Large bodies of water Lake  HEAT SOURCE- Heat reservoirs which supplies heat to system is called heat source  HEAT SINK- Heat reservoir which receives absorbs heat from the system
  20. 20. 2ND LAW OF THERMODYNAMICS KELVIN –PLANCK’S STATEMENT It is impossible to construct a machine which operates in cycle whose sole effect is to convert heat into equivalent amount of work
  21. 21. 2ND LAW OF THERMODYNAMICS CLAUSIUS STATEMENT  It is impossible to construct a machine which operates in cycle whose sole effect is to transfer heat from LTB to HTB without consuming external work CONCEPT STATEMENT
  22. 22. 22 2nd Law: Clausius and Kelvin Statements  Clausius statement (1850)  Heat cannot by itself pass from a colder to a hotter body; i.e. it is impossible to build a “perfect” refrigerator.  The hot bath gains entropy, the cold bath loses it. ΔSuniv= Q2/T2 – Q1/T1 = Q/T2 – Q/T1 < 0.  Kelvin statement (1851)  No process can completely convert heat into work; i.e. it is impossible to build a “perfect” heat engine. ΔSuniv= – Q/T < 0. 1st Law: one cannot get something for nothing (energy conservation). 2nd Law: one cannot even break-even (efficiency must be less Q1 = Q2 = Q M is not active.
  23. 23. HEAT ENGINE  Thermodynamic system/Device which operate in cycle converts the heat into useful work. HEAT ENGINE HEAT ENGINE
  24. 24. HEAT ENGINE Efficiency = e = W/Qs hot cold hot coldhot hot Q Q Q QQ Q W e 1 !!Kelvins!inmeasuredbe mustrestemperatuThe:Note 1 hot cold Carnot T T e
  25. 25. HEAT PUMP  Thermodynamic system/Device which operate in cycle converts the heat into useful work. Cold Reservoir, TC P Hot Reservoir, TH QH QC WORK
  26. 26. HEAT PUMP & REFRIGERATOR  HEAT PUMP Cold Reservoir, TC R Hot Reservoir, TH QH QC W Cold Reservoir, TC P Hot Reservoir, TH QH QC W
  27. 27. 27 Reversible Engine: the Carnot Cycle  Stage 1 Isothermal expansion at temperature T2, while the entropy rises from S1 to S2.  The heat entering the system is Q2 = T2(S2 – S1).  Stage 2 adiabatic (isentropic) expansion at entropy S2, while the temperature drops from T2 to T1.  Stage 3 Isothermal compression at temperature T1, while the entropy drops from S2 to S1.  The heat leaving the system is Q1 = T1(S2 – S1).  Stage 4 adiabatic (isentropic) compression at entropy S1, while the temperature rises from T1 to T2. Since Q1/Q2 = T1/T2, η = ηr = 1 – T1/T2.
  28. 28. POWER PLANT ENGINEERING PROF. S. S. BABAR (MECHANICAL ENGG. DEPT)
  29. 29. POWER PLANT  HYDROELECTRIC POWER PLANT  THERML POWER PLANT  NUCLEAR POWER PLANT  SOLAR POWER PLANT  WIND POWER PLANT  GEOTHERMAL POWER PLANT  TIDAL POWER PLANT
  30. 30. THERMAL POWER PLANT  COMPONENTS  1. STEAM GENERATOR  2. STEAM TURBINE  3. GENERATOR  4. CONDENSER  5. FEED PUMP
  31. 31. THERMAL POWER PLANT  Cheaper fuels used  Less space required  Plant near the load centers so less transmission cost  Initial investment is less than other plants  Plant set up time is more  Large amount of water required  Pollution  Coal & ash handling serious problem  High maintenance cost ADVANTAGES DISADVANTAGES
  32. 32. HYDROELECTRIC POWER PLANT
  33. 33. HYDROELECTRIC POWER PLANT  RESERVOIR  DAM  TRASH RACK  GATE  PENSTOCK  TURBINE  GENERATOR  TAIL RACE COMPONENTS HYDRO- ELECTRIC PLANT
  34. 34. HYDROELECTRIC POWER PLANT
  35. 35. HYDROELECTRIC POWER PLANT  No fuel required  No pollution  Running cost low  Reliable power plant  Simple design & operation  Water source easily available  Power depends on qty of water  Located away from load center- transmission cost high  Setup time is more  Initial cost - high ADVANTAGES DIS ADVANTAGES
  36. 36. NUCLEAR POWER PLANT
  37. 37. NUCLEAR POWER PLANT
  38. 38. NUCLEAR POWER PLANT
  39. 39. WPUI – Advances in Nuclear 2008 Fission controlled in a Nuclear Reactor Steam Generator (Heat Exchanger) Pump STEAM Water Fuel Rods Control Rods Coolant and Moderator Pressure Vessel and Shield Connect to Rankine Cycle
  40. 40.  Large amount of energy with lesser fuels  Less space  No pollution  Cost of power generation is less  Setup cost –more  Availability of fuel  Disposal of radioactive waste  Skilled man power required  Cost of nuclear reactor high  High degree of safety required ADVANTAGES DIS ADVANTAGES NUCLEAR POWER PLANT
  41. 41. WIND POWER PLANT
  42. 42. WIND POWER PLANT  AIR IN MOTION CALLED WIND  KINETIC ENERGY OF WIND IS CONVERTED INTO MECHANICAL ENERGY  K.E. = (M X V2 )/2  ROTOR  GEAR BOX  GENERATOR  BATTERY  SUPPORT STRUCTURE
  43. 43. WIND POWER PLANT
  44. 44. WIND POWER PLANT  No pollution  Wind free of cost  Can be installed any where  Less maintenance  No skilled operator required  Low energy density  Variable, unsteady, in termittent supply  Location must be away from city  High initial cost ADVANTAGES DIS ADVANTAGES
  45. 45. SOLAR POWER PLANT
  46. 46.  Freely & easily available  No fuel required  No pollution  Less maintenance  No skilled man power req.  Dilute source  Large collectors required  Depends on weather conditions  Not available at night ADVANTAGES DIS ADVANTAGES SOLAR POWER PLANT
  47. 47. THANK YOU
  48. 48. YOU CAN DO THIS

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