Thermodynamic Analyses of an Intercooled Gas Turbine from Ceramic Material

In this paper, the thermodynamic performance of state-of-the-art silicon carbide fiber-reinforced silicon carbide matrix composite (SiCf/SiC)-bladed gas turbines (GTs) are presented. Two different GT power systems are comparatively considered namely; the basic gas turbine (BGT) cycle and the intercooled gas turbine cycle (ICGT). The work analyzes the thermodynamic advantages of adoption of ceramic matrix composite turbine blades to existing GTs featuring traditional single-crystal superalloy-blades. Mathematical models and governing equations pertaining to the interdependent performance parameters namely: blade coolant flow rates, 1st law, and 2nd law thermodynamic efficiencies, and component exergy destruction were converted into computer codes. It was observed that SiCf/SiC-bladed GTs will require 84-85% lesser blade coolant at 1900 K leading to superior thermodynamic performance. The enhancement in the 1st law efficiency and 2nd law efficiency of the SiCf/SiC-bladed BGT systems are observed to be 3% compared to conventional superalloy-bladed systems. Similarly, enhancement in the 1st law efficiency and the 2nd law efficiency of the SiCf/SiC-bladed ICGT systems are observed to be 3%. The SiCf/SiC-bladed GT systems are found to be superior to the single-crystal superalloy-bladed GT as they exhibit lower component exergy destruction. The performance maps suggest that replacing the existing single-crystal superalloy blades GTs with the novel ceramic matrix composite blades would exhibit superior thermodynamic performance even when GT firing temperatures are more than 1800 K. These may be used by utility developers to select suitable technology and sizing of GT systems.

Automated summary

This paper presents the thermodynamic performance of state-of-the-art silicon carbide fiber-reinforced silicon carbide matrix composite (SiCf/SiC)-bladed gas turbines. The study compares two different gas turbine power systems: the basic gas turbine cycle and the intercooled gas turbine cycle. The results show that SiCf/SiC-bladed gas turbines require significantly less blade coolant and exhibit superior thermodynamic performance compared to traditional single-crystal superalloy-bladed systems. The performance maps indicate that replacing existing single-crystal superalloy blades with ceramic matrix composite blades would lead to improved thermodynamic efficiency, even at high firing temperatures.