ECAT: An Engine Component Aerothermal Facility at the University of Oxford

Abstract

This paper describes a new engine-parts facility at the University of Oxford for high technology-readiness-level research, new technology demonstration, and for engine component validation. The Engine Component AeroThermal (ECAT) facility has a modular working section which houses a full annulus of engine components. The facility is currently operated with high-pressure nozzle guide vanes from a large civil jet-engine. A high degree of engine similarity is achieved, with matched conditions of Mach number, Reynolds number, and coolant-to-mainstream pressure ratio. For combustor-turbine interaction studies, a combustor simulator module is used, which is capable of both rich-burn and lean-burn combined temperature, swirl and turbulence profiles. The facility is being used for aerothermal optimisation research (e.g., novel cooling systems, aerodynamic optimisation problems, capacity sensitivity studies), computational fluid dynamics validation (aerodynamic predictions, conjugate predictions), and for component validation to accelerate the engine design process. The three key measurement capabilities are: capacity characteristic evaluation to a precision of 0.02%; overall cooling (metal) effectiveness measurements (using a rainbow set of parts if required); and aerodynamic loss evaluation (with realistic cooling, trailing-edge flow etc.). Each of these three capabilities have been separately developed and optimised in other facilities at the University of Oxford in the last 10 years, to refine aspects of facility design, instrumentation design, experimental technique, and theoretical aspects of scaling and reduction of experimental data. The ECAT facility brings together these three research strands with a modular test vehicle for rapid high technology-readiness-level research, demonstration of new technologies, and for engine component validation. The purpose of this paper is to collect in one place — and put in context — the work that led to the development of the ECAT facility, to describe the facility, and to illustrate the accuracy and utility of the techniques by presenting typical data for each of the key measurements. The ECAT facility is a response to the changing requirements of experimental turbomachinery testing, and it is hoped this paper will be of interest to engine designers, researchers, and those involved in major facility developments in both research institutes and engine companies.

Methodology for High-Accuracy Infrared Calibration in Environments with Through-Wall Heat Flux

“…When IR images are taken, it is typical to select a region of several pixels around the thermocouple junction location to establish an area-averaged radiometric value on the target surface. Moderate lateral temperature gradients are possible because of the nature of the components being studied, as shown, for example in the results of Kirollos et al (2017), which are reproduced in Figure 7. The figure shows a nozzle guide vane non-dimensional surface temperature presented as overall cooling effectiveness θ (the complete definition of θ is described in Kirollos et al, 2017).…”

“…Moderate lateral temperature gradients are possible because of the nature of the components being studied, as shown, for example in the results of Kirollos et al (2017), which are reproduced in Figure 7. The figure shows a nozzle guide vane non-dimensional surface temperature presented as overall cooling effectiveness θ (the complete definition of θ is described in Kirollos et al, 2017). The part was fully cooled (both external film and internal convective cooling) and was operated at conditions non-dimensionally representative of an engine.…”

“…Example of overall cooling effectiveness (θ) measurements(Kirollos et al, 2017) on engine components, showing high lateral temperature variation.…”

Methodology for High-Accuracy Infrared Calibration in Environment with Through-Wall Heat Flux

“…When IR images are taken, it is typical to select a region of several pixels around the thermocouple junction location to establish an area-averaged radiometric value on the target surface. Moderate lateral temperature gradients are possible because of the nature of the components being studied, as shown, for example in the results of Kirollos et al (2017), which are reproduced in Figure 7. The figure shows a nozzle guide vane non-dimensional surface temperature presented as overall cooling effectiveness (the complete definition of is described in Kirollos et al, 2017).…”

“…Moderate lateral temperature gradients are possible because of the nature of the components being studied, as shown, for example in the results of Kirollos et al (2017), which are reproduced in Figure 7. The figure shows a nozzle guide vane non-dimensional surface temperature presented as overall cooling effectiveness (the complete definition of is described in Kirollos et al, 2017). The part was fully cooled (both external film and internal convective cooling) and was operated at conditions non-dimensionally representative of an engine.…”