Thermal Characteristics of Synthetic Jet Impingement at Different Strouhal Numbers for Electronics Cooling

In the present experimental investigation, the effect of Strouhal number on the thermal performance of synthetic jets is studied. Experiments are carried out with an 8 mm orifice diameter plate for two different Strouhal numbers (Sr = 0.04 and 0.66) at constant Re = 2280. The hot wire anemometry is used to gauge the flow velocity, while an Infrared thermal imaging camera is used to study the thermal characteristics. The results showed that Sr plays a significant role in the variation of the heat transfer rate for a given surface distance at constant jet Reynolds number. At a larger surface distance (z/d = 16), a low Sr jet produces 19% better heat transfer than a high Sr jet. However, for a lower surface distance (z/d = 6), a jet with a high Sr exhibits a 9% higher heat transfer rate. Further, by reducing the surface distance up to z/d = 2, unforeseen enhancement in heat transfer is observed with a low Sr. This occurs because of the flow circulation at low surface distance, which would have a more substantial effect at the higher Sr.