Air jet Impingement Study

Abstract

With advancement in electronics, packaging of electronic product has reduced which in turn has made researchers to come up with new techniques on thermal management of electronic devices. Effective heat removal from these products poses a bigger challenge due to lot many constrains or parameters. There has been significant work done by researchers which address heat transfer enhancement. Famous methods include passive and active air jet impingement methods. Passive jet impingement is a mechanism of jet formation without help of any moving parts. It is more of a natural process of jet impingement. In active air jet method, jet formation happens with the help of external moving system. newlineIn Present thesis both methods such as Swirl jet impingement (Passive jet cooling) and pulsating jet impingement (Active jet cooling) are addressed. Both methods are used in experiments, and it is proven that improving heat transfer is achievable with current techniques. When compared to standard swirl jet approaches that use swirl tape for heat transfer enhancement, the new delta swirl technique is found to provide greater heat transfer for flow in the range 1500and#8804;Reand#8804;9000 when considering the passive air jet impingement research domain into consideration. Further a numerical correlation between Re and Pr is established for stagnation region for flow ranging between 3000and#8804;Reand#8804;9000. Further an optimal jet to jet distance is derived using CFD which showcase an optimal coaxial jet distance for better heat transfer. newlineA unique hybrid pulsating approach is developed for pulse frequencies ranging from 0.07 Hz to 0.2 Hz with Re ranging from 1500 to 9000, considering the active air jet impingement study domain. Results clearly demonstrate improved heat transfer enhancement over active pulsating jet impingement currently in use. Further, an attempt is made to understand the effect of the slot air jet on heat transfer using CFD. To demonstrate improved heat transfer, the slot jet uses the swirling technique described above. In contrast to conventio