30th Congress of the International Council of the Aeronautical Sciences

02.2 - Experimental Aerodynamics

MATHEMATICAL MODELS AND OPTICAL INVESTIGATION OF TWO PHASE FLOWS IN WIND TUNNELS

I.A. Amelyushkin, TsAGI, Russia

In present work original algorithms were proposed in order to determine two phase flow parameters in wind tunnels via laser sheet images analysis. Numerical algorithms were developed in order to calculate carrying gas parameters fields (velocity, temperature, pressure, etc.) via processing particles’ velocity fields. Differences of velocities between particles and gas were taken into account. A criterion of two phase velocity nonequilibrium was proposed. Examples of application of new technologies are presented. Aerosol flows with nonspherical ice crystals were also investigated. An optical system and numerical algorithms of image processing (inverse problems’ solutions) were developed in order to visualize two phase flow and to determine particle and droplet concentration (mass, volumetric and numerical) as well as size distribution in laser sheet plane near a solid body in the aerosol flow. Stability of inverse problems’ solutions were proved and investigated. A method of calibration was developed. The plane-parallel laser sheet was formed and used in order to simplify image processing and apply methods of inverse problems’ solution in image analysis. These methods which are devoted for two phase flow parameters determination were developed to take into account some physical effects. rnMathematical models of supercooled water droplets stability and their crystallization were proposed and developed. A comparison of computational results with experimental data is presented. Minimal values of the supercooled droplets impingement speed were measured in order to determine flow parameters when droplets stay liquid ones after collisions with aircraft surface. Original mathematical models of stochastic motion of nonspherical ice crystals and small water droplets were developed. rnLiquid film and supercooled droplets behaviors on nanostructured hydrophobic surfaces were investigated in the icing wind tunnel. O


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