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Reduction of noise, fuel use and pollution emissions from aircraft is seen as one of the highest priorities by the Advisory Council for Aeronautical Research in Europe. In response to environmental goals set by this body and the Kyoto Protocol, VITAL is working on a major advance in developing the next generation of commercial aircraft engine technologies. Potential benefits to the European aero-engine industry include high-performance, low-noise and low-emission engines at an affordable cost. These benefits will also accrue to customers, air passengers and society at large. VITAL's main objective is to achieve a six decibel noise reduction per aircraft operation and a 7% reduction in carbon dioxide (CO2) emissions over engines in service prior to 2000.
Glen Snedden, a researcher at CSIR Defence, Peace, Safety and Security, and his team, will work in subproject 6 "Low Pressure Turbine" with partner Avio SPA (Italy), on experimental turbomachinery and turbine computational fluid dynamics (CFD) for increased engine efficiency, which reduces the quantity of fuel an aircraft needs to take on board and lowers the overall weight.
Areas under investigation in other subprojects include consideration of the modularity of gas turbine engines in general. The role of low speed fans in engine noise reduction and optimisation of the compressor performance are critical areas of investigation. Furthermore, an investigation into the use of advanced lightweight materials incorporated into an engine is further explored, in an effort to minimise the mass of the engine.
Describing the research on the low pressure turbines to be undertaken by the CSIR, Snedden comments, "We will focus on the effects of airfoil wakes (namely unsteady flows) on the performance of non-axisymmetric profiled endwalls of turbine rows. An endwall is the cylindrical surface onto which the turbine blades are mounted; profiling endwalls changes the shape from pure cylindrical to a landscape of mounds and depressions. This change in geometry has been shown to reduce loss generating vortices in the near wall region caused by the low momentum fluid found there."
Design of the profiled endwalls will take place at Avio. "Profiled endwalls are a relatively new development and little is understood about their performance under unsteady conditions,"Snedden explains. "We will do the experimental work at the CSIR in the low-speed rotating axial turbine rig." Numerical work will also be conducted at the CSIR which has a strong track record in CFD calculations, in particular with steady flows; Avio will partner with the CSIR for the unsteady analysis.
As the leader of the CSIR team, Snedden sees this opportunity as a huge personal learning curve; his group of young engineering postgraduate students is equally enthusiastic about the prospect, "Doing measurements in the rotating environment in real time are research challenges that we look forward to."The CSIR is currently developing the knowledge on non-axisymmetric endwall profiling on axial turbines, which includes Snedden's PhD studies registered at Durham University. His team will include Dwain Dunn and Ndumiso Zwane, both enrolling for higher degrees as part of this opportunity.
Dr Kamalluddien Parker, National Contact Point on aerospace for the Department of Science and Technology, remarks, "The nature of our interaction here is indicative of the level of confidence that aerospace OEMs place on our capabilities. This is the first inclusion of South Africa in an aerospace-related research area, funded under the EU FP6 and as such, augurs well for our involvement with other aerospace initiatives. It is imperative that the South African research establishment engages at this level in an effort to re-establish itself in the global aerospace S&T fraternity."
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