Conceptual Design of the Cooling System for 1700°C-Class, Hydrogen-Fueled Combustion Gas Turbines

Abstract

The effects of three types of cooling systems on the calculated operating performances of a hydrogen-fueled thermal power plant with a 1,700°C-class gas turbine were studied with the goal of attaining a thermal efficiency of greater than 60 percent. The combination of a closed-circuit water cooling system for the nozzle blades and a steam cooling system for the rotor blades was found to be the most efficient, since it eliminated the penalties of a conventional open-circuit cooling system which ejects coolant into the main hot gas stream. Based on the results, the water cooled, first-stage nozzle blade and the steam cooled first-stage rotor blade were designed. The former features array of circular cooling holes close to the surface and uses a copper alloy taking advantage of recent coating technologies such as thermal barrier coatings (TBCs) and metal coatings to decrease the temperature and protect the blade core material. The later has cooling by serpentine cooling passages with V-shaped staggered turbulence promoter ribs which intensify the internal cooling.

Novel cycles: oxy-combustion turbine cycle systems

“…Based on model results, further advances in cooling or TBC performance would be needed to allow airfoil operation at the high temperature proposed for the third-generation oxy-fuel application. Novel cooling schemes using liquid or steam cooling have been explored by researchers dating back to the 1980s, who suggested the potential for operation at very high temperature (Caruvana et al ., 1980 ;Horner, 1980 ;Kizuka et al ., 1998 ;Okamura et al ., 2000 ).…”

Heat Transfer Research on a Certain Gas Turbine Blade

“…The continuing thrust towards higher thermal efficiencies of gas turbine has resulted in a continuous increase of the TIT. As a result of this trend industrial gas turbines, such as those used in combined cycle power plants, with TITs of 1500°C are being manufactured and more recently, TITs of 1700°C have been conceptualized [1].…”

Gas Turbines in Unconventional Applications

“…According to Hitachi Kizuka et al (1999) the efficiency of the cycle without cooling system is 61.3% HHV, for the cycle with closed water-steam cooling system is 60.1% HHV, for the cycle with closed steam cooling system is 58.7% HHV and for the cycle with open steam cooling system is 54.7% HHV. Cooling system implementation in those cases has decreased the HHV efficiency respectively about 1.2, 2.6 and 6.4 percentage point.…”

“…A concept of the cooling system for the MNRC-HPT turbine was based on results obtained for the GRAZ cycle by Hitachi Ltd. Kizuka et al (1999); Mouri (1999). Results were transformed to higher parameters and smaller dimensions of the MNRC-HPT turbine flow part.…”