Non-Intrusive Optical Diagnostics of Turbulence in Turbomachinery

START project Y 57 Non-Intrusive Optical Diagnostics of Turbulence in Turbomachinery Jakob WOISETSCHLÄGER 28.06.1996 The research objective of the proposed program is the improvement of turbulent flow modelling in gas and steam turbomachinery by non-intrusive optical flow diagnostics. Since the flow physics in turbomachinery includes laminar-turbulent transitional flows, rotational forces, fully three-dimensional flows, pronounced pressure gradients in all directions, vortices, secondary flows, subsonic and transonic conditions, unsteady phenomena like wake passing and often two-phase flows (steam and water, gas and particles), the turbine gas flow is an ultimate test for turbulent flow calculation. Differences in predicted and measured efficiencies in turbomachinery are believed to be caused by the empirical input to numerical models still needed to represent the turbulent nature of flow. These differences are large enough for not being able to replace expensive experimental tests by numerical calculation process. The proposed program attacks this problem by the use and development of non-intrusive optical diagnostic techniques for turbulent flows in turbomachinery.