Dual Synthetic Jets Actuator and Its Applications-Part III: Impingement Flow Field and Cooling Characteristics of Vectoring Dual Synthetic Jets

In order to understand the impingement flow field and cooling characteristics of vectoring dual synthetic jets (DSJ), an experimental investigation was performed to analyze the parameter effects. With the variation of the slot location, the vectoring angle of DSJ can be adjusted from 34.5 degrees toward the left to 29.5 degrees toward the right. The vectoring function can greatly extend the length of impingement region. There are three local peaks both for the local cooling performance (Nu) and the whole cooling performance (Nu(avg)). Although the peak Nu at a certain location of the slider is higher than that at the center, the corresponding Nu(avg) is lower. As for different driving frequencies, the vectoring angle reaches its minimum of 9.7 degrees at 350 Hz, but the Nu is obviously improved. There is one local peak of Nu(avg) values at 350 Hz rather than three local peaks at 250 Hz and 450 Hz. The slot locations where the Nu(avg) of 250 Hz and 450 Hz reach maximum are different. With the increase in driving voltage from +/- 100 V to +/- 200 V, the vectoring angle drops from 46.9 degrees to 22.2 degrees, but both Nu and Nu(avg) are improved. The maximum Nu(avg) of each driving voltage occurs at the center location of the slider. The choking effect and the cross flow have dominated the vectoring angle and the cooling performance of impingement DSJ. Vectoring DSJ will give impetus to the thermal management of large-area electric devices in spaced-constrained cooling and removing dynamic hotspots.