Session: 13-01: Heat transfer in turbines engine testing

Paper Number: 151270

Infrared Heat Transfer Coefficient Measurements in an Engine-Scaled Turbine Stage 

Predicting the effects of combustor turbulence, hot spot location and migration on turbine stage heat transfer remains a challenge, even for state-of-the-art design methods. As such, heat transfer measurements are required. This paper presents full-field, spatially resolved heat transfer coefficient measurements using infrared thermography in an engine-scaled, partially cooled turbine stage test rig at the NG-Turb facility in DLR Göttingen, carried out as part of the European Commission-funded FACTOR programme. The work utilises a traditional transient measurement method and a novel phase-based technique. Measurements were made on stationary vanes and struts and in the rotating frame on the rotor blades. The phase-based technique exploits the phase-shift between oscillating fluid and wall temperatures, which varies with local heat transfer coefficient. This approach enhances spatial resolution by an order of magnitude, increases robustness against measurement noise and calibration, and lowers the heating power input requirements compared to the traditional transient method. The research methodology is detailed, including the mechanical design of the composite blades and infrared windows. The static and in-situ calibrations of the infrared camera are described in detail. In-situ calibrations are performed using near-surface mounted thermocouples, with the rotating frame thermocouples monitored via a telemetry unit. Data collection and post-processing procedures are documented. Finally, full-field data is presented as Nusselt numbers on a film-cooled nozzle guide vane, a rotor blade, and a low pressure strut.

Presenting Author: William Davis University of Cambridge

Presenting Author Biography: William Davis is a final year PhD student at the Whittle Laboratory, University of Cambridge. After completing his undergraduate studies at Cambridge he joined the Centre for Doctoral Training in Future Propulsion and Power, working on an MRes and PhD project on infrared thermography techniques with Dr Nick Atkins. His research focuses on improving heat transfer measurement and flow visualisation methods to reduce the time and cost of turbomachinery research.

Authors:

William Davis University of Cambridge
William Playford University of Cambridge
Aurélien Perrot University of Cambridge
Max Hewkin-Greggor University of Cambridge
Julien Desset Von Karman Institute for Fluid Dynamics
Tony Arts Von Karman Institute for Fluid Dynamics
Nicholas R. Atkins University of Cambridge