Effect of transverse synthetic jet on heat transfer characteristics of the heat sink situated in a rectangular channel with axial main flow

Abstract

This study experimentally investigated the heat transfer characteristics of the heat sink situated in a rectangular channel with the axial main flow under a transverse synthetic jet. The heat sinks, made of aluminum alloy, were divided into three kinds: the finned heat sinks, the in-line pin-fin heat sinks and the pure aluminum-foam heat sink. Total 7 heat sinks were used as test specimens. There was a fixed bypass space between the heat sink and the upper cover of the channel. The synthetic-jet device was separately placed above the leading edge of heat sink, normally above the heat sink and above the trailing edge of heat sink. Under current test parameters, the heat transfer capability of the system with the synthetic jet was around four times that without the synthetic jet. When the value of Rej/Re was bigger than 2.4, the synthetic jet would enhance the heat transfer of the present cooling system above 50%. The cases with the smaller diameter of synthetic-jet nozzle had the better heat transfer enhancement. The Nusselt number of the pure aluminum-foam heat sink was the lowest, and its heat transfer was lower than that of the highest group by 30 ~ 40%.