Enhancement of natural convection using synthetic jets

Natural convection air-cooling is the method of choice for many low power electronics applications due to cost, availability, and reliability. However, its performance is very limited due to buoyancy dependent flow. Therefore, there is a need for further enhancement of natural convection. Enhanced natural convection will allow higher heat dissipation and still largely maintains the simplicity of passive cooling. This paper presents an experimental study on synthetic jet assisted heat transfer on a vertical hot finned plate. Synthetic jets generate pulsed airflow concurrent with buoyancy driven flow. Tests were conducted with a single jet to investigate the effect of jet placement on heat transfer enhancement, while multiple jets were tested to understand how thermal performance changes with the number of jets. As jet placement and the number of jets were varied, local temperature on the plate surface was measured. Comparing natural convection results with and without synthetic jet enhancement, local and average enhancements of heat transfer were quantified. It was found that the cooling enhancement increases with the number of jets, and is sensitive to jet placement. The results show that 3 times enhancement can be achieved with coefficient of performance of 47.