Synthetic jet is a new technique for electronic chip
cooling, which combines stagnant air to form a jet resulting from
periodic diaphragm oscillations in a cavity. In this work, the heat
transfer characteristics of a synthetic jet are investigated
experimentally and numerically. A Piston-cylinder arrangement
powers the synthetic jet through a circular orifice for the
impingement of jet on the heated surface. Air is considered as the
cooling medium. The major parameters identified to describe the
impinging jet heat transfer are Reynolds number, frequency, ratio
of jet spacing to diameter(Z/D) and nozzle geometry. Numerical
studies have been carried out using the finite volume based
commercial software ANSYS Fluent. The turbulent model used
is k-ω model. The dimensionless distance between the nozzle and
plate surface is in the range 2 to 16. Numerical results are in fair
agreement with experimental results. As the frequency increases
the average Nusselt number increases. High frequency synthetic
jets were found to remove more heat than low frequency jets for
small Z/D ratio, while low frequency jets are more effective at
larger Z/D ratio. Nusselt number is maximum at the stagnation
point and there occurs a secondary peak at lower Z/D ratios.
Synthetic jet with rectangular orifice is more effective as
compared to circular and square geometries.
Effects of Frequency and Jet to Surface Spacing on Synthetic Jet Impingement Heat Transfer
