{"id":17272,"date":"2018-03-19T13:10:57","date_gmt":"2018-03-19T13:10:57","guid":{"rendered":"http:\/\/sitepourvtc.com\/?page_id=17272"},"modified":"2022-11-10T12:38:44","modified_gmt":"2022-11-10T12:38:44","slug":"cyclic-process","status":"publish","type":"page","link":"https:\/\/sitepourvtc.com\/nuclear-engineering\/thermodynamics\/thermodynamic-processes\/cyclic-process\/","title":{"rendered":"Cyclic Process"},"content":{"rendered":"
A process that eventually returns a system to its initial state is called a cyclic process<\/strong>. After a cycle, all the properties have the same value they had at the beginning.<\/div><\/div>\n
\"Cyclic<\/a>
A process that eventually returns a system to its initial state is called a cyclic process.<\/figcaption><\/figure>\n

For such a process, the final state<\/strong> is the same as the initial state<\/strong>, so the total internal energy<\/strong><\/a> change must be zero. Steam<\/a> (water) that circulates through a closed cooling loop undergoes a cycle. The first law of thermodynamics<\/a> is then:<\/p>\n

dEint<\/sub> = 0, dQ = dW<\/span><\/strong><\/p>\n

Thus, the process’s network must equal the net amount of energy transferred as heat. It must be noted, according to the second law of thermodynamics<\/a><\/strong>, not all heat provided to a cycle can be transformed into an equal amount of work. Some\u00a0heat rejection<\/strong> must take place.<\/p>\n

Example of Cyclic Process – Brayton Cycle<\/h2>\n
\"first<\/a>
The ideal Brayton cycle consists of four thermodynamic processes. Two isentropic processes and two isobaric processes.<\/figcaption><\/figure>\n

Let assume the\u00a0ideal Brayton cycle<\/strong>\u00a0that describes the workings of a\u00a0constant pressure<\/strong>\u00a0heat engine<\/strong>.\u00a0Modern gas turbine<\/strong>\u00a0engines and\u00a0airbreathing jet engines<\/strong>\u00a0also follow the Brayton cycle. This cycle consist of four thermodynamic processes:<\/p>\n

The ideal Brayton cycle consists of four thermodynamic processes. Two isentropic processes and two isobaric processes.<\/p>\n

    \n
  1. Isentropic compression<\/strong> \u2013 ambient air is drawn into the compressor, pressurized (1 \u2192 2). The work required for the compressor is given by\u00a0WC<\/sub>\u00a0= H2<\/sub>\u00a0\u2013 H1<\/sub>.<\/strong><\/li>\n
  2. Isobaric heat addition<\/strong> \u2013 the compressed air then runs through a combustion chamber, burning fuel, and air or another medium is heated (2 \u2192 3). It is a constant-pressure process since the chamber is open to flow in and out. The net heat added is given by Qadd<\/sub>\u00a0= H3\u00a0<\/sub>– H2<\/sub><\/strong><\/li>\n
  3. Isentropic expansion<\/strong> \u2013 the heated, pressurized air then expands on a turbine, gives up its energy. The work done by the turbine is given by WT<\/sub>\u00a0= H4<\/sub>\u00a0\u2013 H3<\/sub><\/strong><\/li>\n
  4. Isobaric heat rejection<\/strong> \u2013 the residual heat must be rejected to close the cycle. The net heat rejected is given by\u00a0Qre<\/sub>\u00a0= H4\u00a0<\/sub>– H1<\/sub><\/strong><\/li>\n<\/ol>\n

    See also: Thermal Efficiency of Brayton Cycle<\/a>.<\/p>\n

    \u00a0
    <\/span>References:<\/div>
    Nuclear and Reactor Physics:<\/strong>\n
      \n
    1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading,\u00a0MA (1983).<\/li>\n
    2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.<\/li>\n
    3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.<\/li>\n
    4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering,\u00a0Springer; 4th edition, 1994, ISBN:\u00a0978-0412985317<\/li>\n
    5. W.S.C. Williams. Nuclear and Particle Physics.\u00a0Clarendon Press; 1 edition, 1991, ISBN:\u00a0978-0198520467<\/li>\n
    6. Kenneth S. Krane. Introductory Nuclear Physics, 3rd Edition, Wiley, 1987,\u00a0ISBN:\u00a0978-0471805533<\/li>\n
    7. G.R.Keepin. Physics of Nuclear Kinetics.\u00a0Addison-Wesley Pub. Co; 1st edition, 1965<\/li>\n
    8. Robert Reed Burn, Introduction to Nuclear Reactor Operation, 1988.<\/li>\n
    9. U.S. Department of Energy, Nuclear Physics and Reactor Theory.\u00a0DOE Fundamentals Handbook,\u00a0Volume 1 and 2.\u00a0January\u00a01993.<\/li>\n<\/ol>\n

      <\/strong>Advanced Reactor Physics:<\/strong><\/p>\n

        \n
      1. K. O. Ott, W. A. Bezella, Introductory Nuclear Reactor Statics, American Nuclear Society, Revised edition (1989), 1989, ISBN: 0-894-48033-2.<\/li>\n
      2. K. O. Ott, R. J. Neuhold, Introductory Nuclear Reactor Dynamics, American Nuclear Society, 1985, ISBN: 0-894-48029-4.<\/li>\n
      3. D. L. Hetrick, Dynamics of Nuclear Reactors, American Nuclear Society, 1993, ISBN: 0-894-48453-2.\u00a0<\/span><\/li>\n
      4. E. E. Lewis, W. F. Miller, Computational Methods of Neutron Transport, American Nuclear Society, 1993, ISBN: 0-894-48452-4.<\/li>\n<\/ol>\n

        Another References:<\/p>\n

          \n
        1. Car Recycling<\/a><\/li>\n<\/ol>\n<\/div><\/div><\/div>
          <\/div><\/div><\/div>
          <\/div>
          <\/div><\/div>
          \n

          See above:<\/h2>\n

          Thermodynamic Processes<\/i> <\/span><\/a><\/p><\/div><\/div>

    As can be seen, we can describe and calculate (e.g.,, thermal efficiency<\/a>) such cycles (similarly for\u00a0Rankine cycle<\/strong>) using\u00a0enthalpies<\/a>.<\/p>\n