The experimental investigation deals with the aerodynamics and mixing inside of a flue and was financially supported by the German Ministry for Education and Science (BMBF). The design of the model combustion chamber is based on a „Tuboannular Combustion Chamber“. The air flows inside the combustion chamber is characterised by high turbulence and strong streamline curvature. These air flows cannot be determined analytically. Instead of doing expensive measurements, it is more economical to introduce modern computational processes to predict the air flow phenomena inside the combustion chamber. To compute the air flow, turbulent models are used. For their verification and validation an experimental data base is required. The necessary verification experiments can be achieved with a simplified design of a test rig and is therefore more economical than doing the measurements with a real combustion chamber. To determine the essential data base, such a test rig was manufactered. With this test rig, the isothermal air flow inside the Combustion Chamber can be simulated under real working conditions (Reynolds’number, expansion ratio and the geometry of the flue). A laser measurement technique was used to characterise the air flow. The advantage is a non-touching and thus undisturbed determination of these essential data. The Laser-Doppler-Velocimetry (LDV) is marked out with a high time resolution and was used to measure the inlet conditions. Outstanding questions with respect to the gradients and the sign of the velocity profiles were answered. Further dimensionless values were determined, including the normalized turbulent kineticl energy and the experimental swirl intensity S. These values are necessary to characterise the inlet air flow before the sudden expansion in the flue occurs. The Particle-Image-Velocimetry (PIV) records the formation of a full developed recirculation zone. The formation of the recirculatiuon zone occurs in five steps, whereby three different structures are observed (a concentric ring structure, a torsioned ring structure and the full developed recirculation zone in the center of the flue). The concentration measurement technique, which was used, is called the Quantitative Light Sheet Process (QLS).This kind of concentration measurement technique is based on the elastic scattering of laser light (Mie rays) from particles uniformly in the main flow. It is assumed that the local intensity of the scattered light is proportional to the concentration of the particles in the light sheet. The setup includes a commercial PIV system. The resolution of the concentration measurement technique depends on the scattered light concentration. The steps of image processing are described, with respect to seeding intensity fluctuations, the laser beam intensity profile, the laser divergence, angular depence of the scattering, background light, dark current and noise of camera. Therefore new software was developed to correct all the influences with respect to full image resolution. For classification of mixing processes, a new defination of the averaged concentration and the unmixedness was introduced, which allows a local concentration distribution with respect to a global averaged concentration. These helps to understand the physics of mixing within the combustor and was not examined before this work. The obtained data are of great interest for developers of turbulence models, for engineers who design combustion chambers and for researchers who study the physics of mixture processes. The results can be used to increase the efficiency of combustion and to reduce emissions.