https://server.s4e2.com/crc/tcnpp/chapters/appendix2/index.html⚙️ Appendix 2: Turbines Everything You Need to Know About Steam and Gas Turbines Operating Principles: Axial stages: Nozzle acceleration → rotor energy conversion. Key Phenomena: Choked flow: Sonic limit in nozzles (expansion ratio > 2). Degree of reaction: Impulse vs. reaction turbines. Fundamental Laws: Stodola’s Law: Flow vs. inlet/outlet conditions. Baumann’s Rule: Efficiency degradation with steam quality. Gas Turbines Comparison: Type Working Fluid Pressure Materials Cooling Maintenance Steam Water/steam 50-300 bar Alloy steel Moderate High Closed-cycle gas He/CO₂ 100-300 bar High-temp alloys Critical Complex Open-cycle gas Combustion gases 10-30 bar Superalloys Very critical Very high Abstract This appendix provides details on turbines used in steam and gas power plants, focusing on design principles, performance characteristics, and operational considerations. Turbines are introduced through analysis of velocity and pressure profiles in axial turbine stages, where fluid expansion occurs in two steps: stator nozzles accelerate the flow while rotors convert available enthalpy into mechanical energy. Performance maps demonstrate the choked flow phenomenon occurring when expansion ratios exceed approximately 2, establishing a corrected mass flow rate limit at sonic conditions in nozzle throats. The degree of reaction concept is explained, distinguishing impulse turbines from reaction turbines. The concepts of isentropic and polytropic efficiency are presented. The Stodola law relating turbine flow to inlet-outlet conditions is reviewed in multiple forms, from simple to complex formulation accounting for wet zone flows. Baumann’s rule quantifies expansion efficiency degradation with steam quality, showing approximately one percentage point reduction per quality point decrease below saturation. Gas turbines section contrasts closed-cycle systems using inert working fluids (helium, CO₂) at high pressures with combustion turbines operating on flue gases at lower pressures, highlighting differences in materials, cooling requirements, blade design, maintenance needs, and operational stability.Hugoen-usThu, 22 Jan 2026 14:36:36 +0100https://server.s4e2.com/crc/tcnpp/chapters/appendix2/_toc/index.htmlThu, 22 Jan 2026 14:35:10 +0100https://server.s4e2.com/crc/tcnpp/chapters/appendix2/_toc/index.htmlTable of Contents — Volume 2 Advanced Modeling of Thermodynamic Cycles of Nuclear Power Plants Appendix 2 – Turbines A2.1 Steam Turbines A2.2 Gas Turbines A2.3 Conclusion A2.4 Referenceshttps://server.s4e2.com/crc/tcnpp/chapters/appendix2/_resources/index.htmlThu, 22 Jan 2026 14:36:36 +0100https://server.s4e2.com/crc/tcnpp/chapters/appendix2/_resources/index.htmlResources 📘 Appendix 2: Turbines and Stodola’s Law Complementary Resources and Methodological Guides ⚠️ Important Notes About These Resources The resources on this page complement the content of Appendix 2 in Advanced Modeling of Thermodynamic Cycles of Nuclear Power Plants. Models and examples are accessible online but require the Thermoptim software for full interactivity. Download Thermoptim here to access the complete features. Some resources are historical examples from the Thermoptim portal, while others are updated models developed specifically for the book. They should not have any consequences on the understanding of the presented concepts. 📌 Turbines and Stodola’s Law Key Concepts Covered: Analysis of flow and efficiency in turbines and compressors. Transition from the polytropic approach to the isentropic approach Application of Stodola’s law in turbomachinery. Integration of Stodola’s law in Thermoptim models. Complementary Resources: 🔄 Guided Exploration C-M1-V3: Steam power plants with reheat GE: C-M1-V3: Steam power plants with reheat → This GE provides explanations on the polytropic concept.