Cel One of the main problem areas for theoretical design and optimization of turbomachine blades for multistage compressors and turbines is the prediction of transition, both starting position and length. As transition affects the structure of the boundary layer developing on a blade it plays a very significant role on the aerodynamics and the heat transfer of both compressors and turbines. For compressors and low pressure turbines the separation process present is closely tied to transition, so transition does not only affect the design losses but also very significantly affects the off-design behaviour of a turbomachine. Furthermore the cooling system design of a blade is significantly affected by transition. Therefore theoretical modelling, design and optimization of compressor and turbine blades requires detailed and accurate knowledge of the transition process under realistic turbomachinery flows. In this Focused Fundamental Research project, measurements using hot-wire anemometry, Laser Doppler Anemometry and flow visualization will be taken on plates with realistic leading edge geometries and pressure distributions similar to those encountered on blades in compressors and turbines. The objectives of the project are: - To study the effects on transition of moving wakes, longitudinal pressure gradients, incidence, and turbulence structure. - To validate and improve computer models of transition.The project is structured in two principal research areas: Experimental Modelling of Wakes At first the effects of the main constituents of a blade wake on three different leading edge geometries will be studied separately. The individual information will be used as a basis for the modelling of these effects and the interpretation of the data and validation of models on a complete wake transition interaction. A second step is to identify the effects of the passing wakes on transition. Conditional sampling of velocity and flow visualization will be used to identify not only the transition characteristics but also the relaxation of transition and its propagation as a function of frequency and wake size. Furthermore the transition over turbine blades will be studied. For a given typical pressure gradient representative of a blade of current interest, transition on a flat plate representing the blade will be studied for two different leading edge geometries, a circular one and a leading edge designed to eliminate, in conjunction with the shaped wall, the laminar separation usually present on a circular leading edge geometry. The study will be carried out for a range of turbulence intensities and Reynolds numbers. In addition a study of transition on compressor blades will be carried out. The pressure field will be simulated by contouring the walls of the wind-tunnel and it will be representative of a controlled diffusion blade. A variety of Reynolds numbers and free stream turbulence intensities will be used. Computational Modelling of the Effects of the Wakes on Transition The second part of this project will cover the computational aspects and the modelling of transition. The data obtained above will be of high quality in order to be used on test cases for the prediction of transition. For this task the data will be available to a group of researchers from Universities and industry. Various low Reynolds Number turbulence models, Reynolds stress turbulence models, large eddy simulation techniques will be tried and evaluated against the experimental data. Furthermore correlations already available will be tried, or new ones will be developed based on the experimental data. Dziedzina nauki engineering and technologymechanical engineeringthermodynamic engineeringnatural sciencesphysical sciencesclassical mechanicsfluid mechanicsfluid dynamicsnatural sciencesmathematicspure mathematicsgeometryengineering and technologymechanical engineeringvehicle engineeringaerospace engineeringaeronautical engineeringnatural sciencesphysical sciencesopticslaser physics Program(-y) FP3-AERO 1C - Specific programme of research and technological development in the field of industrial and materials technologies - Aeronautics research -, 1990-1994 Temat(-y) Data not available Zaproszenie do składania wniosków Data not available System finansowania CSC - Cost-sharing contracts Koordynator Aristotelian University of Thessaloniki Wkład UE Brak danych Adres 54006 THESSALONIKI Grecja Zobacz na mapie Koszt całkowity Brak danych Uczestnicy (3) Sortuj alfabetycznie Sortuj według wkładu UE Rozwiń wszystko Zwiń wszystko CRANFIELD UNIVERSITY Zjednoczone Królestwo Wkład UE Brak danych Adres Wharley End, Cranfield MK43 0AL Cranfield - Bedfordshire Zobacz na mapie Koszt całkowity Brak danych Rolls Royce plc Zjednoczone Królestwo Wkład UE Brak danych Adres 65 Buckingham Gate SW1E 6AT London Zobacz na mapie Koszt całkowity Brak danych VRIJE UNIVERSITEIT BRUSSEL Belgia Wkład UE Brak danych Adres 2,Pleinlaan 2 1050 BRUSSEL Zobacz na mapie Koszt całkowity Brak danych
