People are pushing turbine inlet temperature to extremes to achieve higher power and efficiency. Material scientists have contributed a lot to developing the most durable material under high temperatures such as special steels, titanium alloys and superalloys. However, turbine inlet temperature can be as high as 1700˚C  and cooling has to be integrated to the system to prolong blade life, secure operation and achieve economic viability.
A high pressure turbine can use up to 30% of the compressor air for cooling, purge, and leakage flows, which is a huge loss for efficiency. It is worth it only if the gain of turbine inlet temperature can outweigh the loss of cooling. This applies to both aviation engines and land based gas turbines.
The history of turbine cooling goes back 50 years and has evolved to fit different environments. The diversity of turbine cooling technology we see today is just the tip of the iceberg. As time goes on and technology advances, people are able to achieve higher cooling efficiency at lower coolant usages. For different goals and needs, different constructs can be applied but the detailed cooling design must balance with the whole system and make the most of technological advances in the areas. For example, if the flow path is optimized, mechanical design is modified, or if new material is employed, the cooling design needs to change accordingly. One thing worth mentioning is that manufacturing of hot section components and turbine cooling design have an interdependent cause and effect, outpacing and leading each other to new levels. Merging of disciplines and additive manufacturing will, in the future, bring more flexibility to turbine cooling design.
Turbine cooling design is sophisticated because hot gas paths are complex in nature.  There are numerous factors that need to be taken into account including:
- Airfoil loadings
- Surface roughness
- Freestream turbulence
- Freestream swirls
- Rotational effects
- Wake effects
In engineering we need a simpler solution with full respect to these physics complexities and AxSTREAM NET might be the answer. AxSTREAM NET is a 1D thermal fluid system design and analysis tool developed for cooling and secondary flow design. It works independently or as a module in the integrated AxSTREAM platform.
For more information, please visit: http://www.softinway.com/software-applications/cooling-flows-secondary-systems/ and if you have any questions, feel free to contact our team or send us an email to set up a demonstration!
- Evaluation of the Gas Turbine Inlet Temperature with Relation to the Excess Air, Fernandorueda Rueda Martínez, Aldo Antonio Rueda Martínez, Miguel Toledo Velázquez, Pedro Quinto Diez, Guilibaldo Tolentino Eslava, Juan Abugaber Francis, Energy and Power Engineering, 2011, 3, 517-524
- Evolution of Turbine Cooling, Gas Turbine Scholar Award Lecture, Dr. Ron S. Bunker, Turbo Expo 2017
- Takeishi, K., Matsuura, M., Aoki, S. and Sato, T., (1989), “An experimental study of heat transfer and film cooling on low aspect ratio turbine nozzles”, ASME 89-GT-187.