Loading...

Developing Optimal Model of a Magnetohydrodynamic Generator Based Combined Cycle

Biria, Aisa |

588 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39111 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Saboohi, Yadollah
  7. Abstract:
  8. Considering the growing global electricity demand and declining world's fossil fuel resources, developing methods to improve thermal power plants' efficiency and power is of great importance. One method to increase cycle's efficiency is to increase cycle's maximum temperature. MHD generators can be added as a topping cycle to ordinary gas turbine-steam combined cycles, thus increasing cycle's maximum temperature to up to 3000K. In this study a MHD-Gas Turbine-Steam combined cycle has been modeled and optimized. In the high temperatures associated with combustion products plasma, diverse molecular decomposition and ionization processes progress. Therefore, equations of mass, energy, and electric charge conservation together with chemical equilibrium equations should be solved simultaneously in order to simulate the combustion chamber. The equations of energy, momentum and continuity for MHD generator control volume were converted to one-dimensional equations and were solved, assuming fluid velocity to be constant. Optimization problem was solved using direct search method were total efficiency was the objective function. Steam turbine inlet temperature and pressure, stack temperature, steam reheat pressure, and MHD pressure ratio are optimization variables which are constrained with technical restrictions. The optimum cycle's efficiency can reach values more than 64% for MHD inlet temperatures more than 2800K that may be increased by 3% with a 100K increment in the temperature. Sensitivity analysis demonstrates that an increase in the bottoming cycle's maximum temperature would reduce total efficiency if it was as a result of decreasing MHD generator's output pressure, while it would increase total efficiency if it was caused by oxidant preheat temperature reduction
  9. Keywords:
  10. Combined Cycle ; Modeling ; Optimization ; Magnetohydrodynamic Power Plant

 Digital Object List

 Bookmark

No TOC