Part-load performance of a pure H ₂ /O ₂ gas turbine cooled by steam from a bottoming-cycle

Hydrogen energy is one of the most attractive renewable resources for mitigating environmental problems and achieving a zero-emission future. Hydrogen-fueled gas turbine power generation is one of the most promising technologies to utilize hydrogen energy. Due to the peak shaving tasks, hydrogen-fueled gas turbines often deviate from the design operating point. Therefore, in this paper, an analysis of the part load performance of a cooled three-spool pure hydrogen-fueled gas turbine for the R-Graz cycle is implemented. Both the mainstream working medium and coolant are steam. Considering the complex physical properties of steam, a novel equation for the evaluation of the mixing loss caused by film cooling is proposed to improve the accuracy of the assessment. Within the load range of 50% to 100%, the results indicate that the isentropic efficiency is dependent on the uncooled polytropic expansion and cooling process. Coolant consumption analysis under part load conditions reveals that the power turbine consumes more than half the coolant, while the high-pressure turbine uses less than 20%. The coolant consumption proportion of the three rotors basically does not change with the load. At last, the coolant cooling technology is considered to improve the total isentropic efficiency and reduce the coolant consumption.