Electronic Cooling Using Synthetic Jet Impingement

Abstract

The efficiency and mechanisms of cooling a constant heat flux surface by impinging synthetic jets were investigated experimentally and compared to cooling with continuous jets. Effects of jet formation frequency and Reynolds number at different nozzle-to-surface distances (H∕d) were investigated. High formation frequency (f=1200Hz) synthetic jets were found to remove heat better than low frequency (f=420Hz) jets for small H∕d, while low frequency jets are more effective at larger H∕d. Moreover, synthetic jets are about three times more effective in cooling than continuous jets at the same Reynolds number. Using particle image velocimetry, it was shown that the higher formation frequency jets are associated with breakdown and merging of vortices before they impinge on the surface. For the lower frequency jets, the wavelength between coherent structures is larger such that vortex rings impinge on the surface separately.

Kryterium powstawania strugi syntetycznej

“…Na podstawie zarejestrowanego modułu prędkości dokonano inwersji połówki sinusoidy odpowiadającej za cykl zasysania powietrza do komory. Wykorzystano w tym celu procedurę opisaną w pracy [5].…”

Heat transfer and air temperature measurements of an impinging synthetic air jet

“…Comprehensive studies have been undertaken into the fluid flow and heat transfer characteristics of impinging synthetic jets [1,4,6,13]. These studies present data highlighting the effect Reynolds number and stroke length has on heat transfer to the synthetic jet by measuring parameters such as flow velocity, turbulence intensity and vorticity.…”

“…Comprehensive reviews of heat transfer to impinging synthetic air jets have been conducted by Gillespie et al [4], Wang et al [5] and Pavlova and Amitay [6] amongst others. Campbell et al [7] conducted a review of heat transfer to an impinging synthetic jet for a wider range of parameters that included varying the number of jets in a jet array, various levels of confinement and the addition of cross flow.…”

Cold Zone Exploration Using Position of Maximum Nusselt Number for Inclined Air Jet Cooling

“…Pulsating flow increases mixing, which increases turbulence and then heat transfer. Such jets are efficient with saving energy, and for their special flow patterns generated which create turbulence and enhance heat transfer [21,22].…”