The project involves near wall hydrodynamical, mass and heat transfer studies in turbulent flows with complex geometry. The project has been stimulated by the necessity to test the classical form of the Reynolds analogy and to develop new types of momentum/heat/mass transfer analogies suitable for engineering applications. The main activities of the project are related with two axis. The first one is the development of electrochemical diagnostics for hydrodynamical and mass transfer measurement in turbulent flows with complex geometry. This experimental method allows one to provide simultaneous measurements of the local wall shear stress and the local mass transfer coefficient. In order to provide these measurements a new design of electrochemical probes was used : a working microelectrode (cathode) is embedded into another cathode of a large surface. For fabrication of these probes two technologies were used : sticking of a nickel or a platinum wire into a nickel tablet and a microlithography technique.
In order to obtain detailed information about wall shear stress a three-segmented design of electrochemical probes was used as well. Moreover, a delay-time modification of electrodiffusion diagnostics was used which allows one to provide measurements in some industrial and natural electrolytes (sea water, for example). Until now the experiments involved three flow configurations : a one-four scale model of membrane flow-type chamber electrolyzer; the flow downstream of a sudden expansion; a prototype of a batch reactor. Another axis of the research activities was related with numerical simulation of the mass/heat transfer and the near wall hydrodynamics. The numerical codes FLUENT and FIDAP were used. Two configurations were studied: flow around flash mounted micro-obstacle and flow in an annular (including the inlet region where the flow has three dimensional characters).