Experimental Analysis of the Turbulent Flow Behavior of a Textured Surface Proposed for Asymmetric Heat Exchangers
Résumé
In this study the Stereoscopic Particle Image Velocimetry (S-PIV) technique was used to analyze the aerodynamic behavior of a textured surface. This textured surface is supposed to cover the inside of the hot wall of asymmetric heat exchangers. A high heat transfer coefficient and a low pressure drop are desired for the studied module receiver. The proposed textured geometry consists of an association of actuators (i.e., vortex generators) and riblets (used as vortex handlers). To determine the flow structure near the walls with good accuracy, an experiment was carried out in a large-scale boundary layer wind tunnel. The post-processing of the velocity fields obtained with the S-PIV technique allows us to obtain indicators of the pressure drop and of the heat transfer coefficient even if the stream is isothermal for these experiments. Nine riblet-actuator couples are studied and compared to the results obtained for an untextured surface. This work points out that the configuration including actuators and riblets of large dimensions is the best performing. This result is qualitatively validated by the analysis of the three components and two-dimensional averaged velocity fields.