Étude expérimentale d'une interaction de jets obliques avec un écoulement transversal compressible. I. Effets de la compressibilité en régime subsonique sur les champs aérothermiques

Abstract

Experimental study of inclined jets cross flow interaction in compressible regime. I. Effect of compressibility in subsonic regime on velocity and temperature fields. The results of the investigation of the interaction of a row of jets with a compressible cross flow are compared with their counterpart obtained in incompressible regime. The comparison reported here focuses on the flow field resulting from the interaction above and at the wall. The velocity and temperature fields are measured respectively by laser Doppler velocimetry and thermocouple probes. The wall temperature distributions are measured using an infrared camera. The experiments are performed for cross flow Mach numbers of 0.72 and 0.1 for respectively the compressible and incompressible regimes with almost the same injection rate ( R=0.50 and 0.6). Significant differences are noticed between the two flow fields in particular on the vertical development of the jets in the cross flow and on the turbulent diffusion. The jet penetration is found to be higher in the compressible regime with less interaction between the jets. The comparison also shows that the wall heat transfer modifications induced by the jets are less pronounced in the compressible case as a result of the higher penetration of the jets. These results show that neither the mass flux ratio nor the momentum ratio are good candidates for extrapolation of the cooling efficiency from the incompressible case to the real compressible case as encountered in the practical applications.