**Author details**

blade cascade with test models. These rigs enable measurements of heat transfer coefficients, film cooling effectiveness, airofoil pressure distributions, and oil flow visualization at engine

In addition to the above tests, the final validation test is conducted in a test gas turbine, which effectively represents the full operating boundary conditions that are prevalent for the entire operating range. For full engine testing, the measurement techniques employed include thermal paint, thermocouples, thermos-crystals, pyrometers, pressure taps, Kiel-Temperature and pressure probes and several other operating instrumentations. **Figure 37** shows a gas turbine with the airofoils painted with thermal paint and the additional instrumentation required to

The aerothermal design of gas turbine components has progressed at a rapid pace in the last decade with all gas turbine manufacturers, in order to obtain higher thermodynamic efficiencies. This has been achieved by using higher turbine inlet temperatures and pressures, advanced turbine aerodynamics, efficient cooling systems for turbine airofoils and advanced

In this chapter, some of the basic heat transfer phenomenon associated with both the external hot gas side and the coolant internal flows in turbine airofoils has been outlined. The external hot gas side heat transfer is largely driven by the unsteady and transonic high pressure and high temperature aerodynamic flows. By establishing the hot gas side external heat loads, which generally varies with different turbine design, it is possible to design for efficient airofoil internal cooling systems. The gas turbine airofoil internal cooling systems are however complex and varied in design, particularly with static and rotating airofoils. The internal cooling design of airofoils generally involves integration of several technology features such

high temperature alloys, metallic coatings, and ceramic thermal barrier coatings.

representative operating conditions.

138 Heat Exchangers– Design, Experiment and Simulation

**7. Conclusion**

validate and monitor the airofoil and engine performances.

**Figure 37.** Gas turbine test engine and instrumentation [2].

Shailendra Naik

Address all correspondence to: shailendra.naik@ansaldoenergia.com

Ansaldo Energia, Baden, Switzerland
