Work Package 3
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| During last years, the continued
trend towards higher turbine inlet temperature and flatter temperature
traverses due to new combustors designs resulted in the new cooling
requirements for turbine endwalls. The need for additional cooling for
platforms is in contrast with engine performance and costs, and
therefore, the development of highly efficient cooling systems and the
use of leakage flows to control the secondary flows near the endwalls
are the most interesting areas of research for static and rotating
endwalls. The latter aspect becomes even more important for high-lift
rotor blades due to the more pronounced secondary flow structures near
the platforms. In the first task, one of the most efficient cooling methodologies in terms of cooling mass flow used would be “transpiration cooling” using a porous material in the most critical areas of the platform. This would allow to use the large internal surfaces, typical of a porous material, for heat exchange and to couple this effect with a very efficient film cooling due to the homogeneous distribution and the low velocities involved. To this date, those materials are not compatible with other application requirements such as the high temperatures and stress levels and the investigations planned in this task represent a major step towards new cooling technology development for industrial application. The use of distributed micro-holes could allow to simulate, in the best possible way, a porous media using the normal metal alloys already available as base material. Geometries to be studied (considering hole diameter between 0.07 – 0.15 mm) must have as requirements the larger internal heat exchange geometry, dimensions and position compatible with manufacturing capability and must be also tested regarding the effects of hole blocking due to debris from upstream engine components. The second task is focussed on the reduction on turbine blade count in order to decrease engine weight and cost by means of high-lift profiles to increase blade loading. The design objective implies that regions of strong adverse pressure gradient, leading to significant portions of |