EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THERMAL PERFORMANCE OF SYNTHETIC JET IMPINGEMENT

Synthetic jet potentially useful in electronics cooling is investigated both numerically and experimentally. In the present study, a confined three dimensional synthetic jet with sinusoidal moving wall is considered. Computations are carried out using the FLUENT software with the coupled user defined function describing the diaphragm movement. In this study the effect of various geometrical parameters influencing the flow field and heat transfer are investigated. The effects of change in orifice geometry (circular, square and rectangular), orifice aspect ratio, and jet-to-plate distance are studied for a given hydraulic diameter. The heat transfer results obtained from the synthetic jet is compared with the continuous jet. An electromagnetic actuator is used as an oscillating diaphragm for the generation of synthetic jet. A stainless steel foil with 0.05 mm thickness is used as the test specimen. The surface temperature of the test specimen is measured by using a thermal imaging technique during synthetic jet impingement and a constant temperature anemometer has been employed for velocity measurement. Tests are carried out for Reynolds number of 5448, varied range of jet-to-plate distance (1- 18). The maximum value of the heat transfer coefficient is found to be 16 times more than the heat transfer coefficient for natural convection.