Investigation of overall cooling effectiveness on a steam-cooled double-wall vane of hydrogen gas turbine with mist injections

Numerical studies were conducted to investigate the conjugate heat transfer characteristics of a mist/steam-cooled high-pressure turbine vane in a hydrogen gas turbine, which was proposed for a hydrogen fuel pure oxygen combustion gas turbine combined cycle with flow bypass and recompression. A double-wall cooling vane operating in a real turbine environment was considered. The effect of mist injections on the overall cooling effectiveness of the steam-cooled double-wall vane of a hydrogen gas turbine was investigated by varying the mist concentration (5% ≤ m_s ≤ 20%) and droplet size (5 μm ≤ d_p ≤ 20 μm). The m_s and d_p have a synergistic effect on the overall cooling effectiveness, and it tends to increase with increasing m_s, especially at the suction side. The highest averaged overall cooling effectiveness of the steam-cooled vane at the mid-span of the vane was obtained at m_s = 20% with a relatively small particle size of 10 μm, which was approximately 11% higher than that without mist, corresponding to an 88.6K drop in the vane’s wall temperature.