NUMERICAL MODELING AND FREQUENCY RESPONSE OF AXISYMMETRIC SYNTHETIC JET

Conrad Yuan Yuen Lee¹; Cássio Alles¹

¹ UNISINOS

doi:10.20906/CPS/COB-2015-1745

Resumo

Synthetic jets are generated by the movement of a membrane inside a sealed cavity with a single opening. The movement of fluid in and out of the cavity produces a synthetic jet with average velocity characteristics similar to a steady jet but with much higher turbulence levels due to its oscillatory nature. This characteristic allows synthetic jets to achieve higher levels of mixing and can consequently greatly enhance or even replace conventional electronic cooling techniques which rely primarily on forced convection of air. In this study, a 3-D numerical model of an axisymmetric synthetic jet with a round orifice and air as the working fluid is constructed with the purpose of analyzing its cooling performance. The jet simulation results show good agreement with other experimental and numerical work. Compressibility effects inside the cavity show that an optimum oscillating frequency of the membrane is needed to maximize the jet Reynolds number and cooling. Results show that average jet velocities increase with oscillating frequency but its effect is limited to the central region of the jet, with little influence on the jet width growth.

Palavras-chave: CFD; synthetic jets; frequency response