59470 - Gt36 Turbine Development and Full-Scale Validation 

GT36 Turbine Development and Full-Scale Validation 

S. Naik, B.Stephan, M. Henze

Ansaldo Energia

CH-5401, Baden, Switzerland

Abstract

This paper describes the turbine aero-thermal development and subsequent extended engine validation of the GT36 heavy duty gas turbine. The turbine which has evolved from the existing and proven GT26 design, consists of an optimised annulus flow path, high lift aerofoils and highly efficient blade cooling systems. Major design features of the gas turbine include, reduced aerodynamic losses and minimised coolant flow consumption which are closely matched to the different operating profiles of the gas turbine. The advantages of these design features to the overall gas turbine performance have been subsequently verified via several extensive engine tests in the GT36 Test Power Plant in Birr, Switzerland. 

The GT36 Test Power Plant is heavily instrumented with thermocouples, pressure sensors, strain gauges, five-hole probes, pyrometers, tip timing sensors and several dedicated instrumentations within the combustor, compressor, rotor and inlet/exhaust housings. In addition to overall transient and steady-state operational and performance mapping of the gas turbine, a dedicated thermal paint validation test has also been performed to validate and map the detailed thermal behaviour of the turbine.

Measurements of engine aerofoil profile local static pressures and metal temperatures for all turbine aerofoils, have shown that the aerodynamic and cooling performances during both transient and steady-state operations are highly consistent and repeatable. Additionally, this has also been observed for the overall turbine pressure and temperature expansion characteristics, from the dedicated row-wise pressure and temperature measurements. The latter was found to match well with the design intent and predictions. Further detailed measurements from thermal paint tests confirmed that the local thermal behaviours of all turbine parts behave consistently with the engine operating conditions. The aerothermal validation of the turbine parts was further confirmed via extensive testing in dedicated high-speed cascades and Perspex models, where measurements were conducted for local film cooling effectiveness, surface pressures, internal flow pressure losses and local heat transfer coefficients.