Gas-Turbine Performance Improvements Through the Use of Multiple Turbine Interstage Burners

The focus of this investigation is to increase the power and thermodynamic efficiency of a gas-turbine engine through the use of multiple interstage burners (MIBs). Liu and Sirignano [(Liu, F., and Sirignano, W. A., "Performance Increases for Gas Turbine Engines Through Combustion Inside the Turbine," Journal of Propulsion and Power, Vol. 15, No. 1, 1999, pp. 111-118), (Liu, F., and Sirignano, W. A., "Turbojet and Turbofan Engine Performance Increase Through Turbine Burners," Journal of Propulsion and Power, Vol. 17, No. 3, 2001, pp. 695-705)] suggest burning fuel in the turbine to achieve high-pressure combustion that can significantly improve engine performance. An extension to the Liu and Sirignano research, including turbine cooling for MIB engines, was performed, and results showed large performance improvements for land-based power production engines. Unfortunately, the investigation showed minimal improvements for aircraft engines due to the large amount of cooling air required to keep turbine surface temperatures below critical limits. Thus, this investigation focused on improvements for land-based energy production engines with MIBs. Furthermore, land-based engine performance may be significantly increased by the use of open-loop or closed-loop steam cooling in conjunction with MIBs. Comparisons of the performance of these engines with open-loop air cooling, open-loop steam cooling, and closed-loop steam cooling were made. Results show that open-loop steam cooling yields the highest net power output and thermal efficiency. In addition, it was discovered that one main burner and one interstage burner, that is, two MIBs, is a good compromise for all three cooling schemes.