Spatio-temporal Heat Transfer Characteristics of Pulsating Co-axial Impinging Jet Cooling

Impinging jets are widely used as a cooling technique in various industrial applications due to their high heat transfer coefficients and simple setup. Co-axial jets, which are comprised of an inner round jet and a surrounding annular jet, introduce additional flow structures that potentially result in higher convective heat transfer footprint. For a given mass flow rate, the flow can be partially diverted into each stream, enhancing certain vorticity features in order to enhance heat transfer. Moreover, active pulsation of each stream separately has the potential to amplify the generated vortex patterns and strengths in the near-field of the coaxial jet. This synergy is expected to further improve the heat transfer beyond that of a single non-excited jet. The aim of this research is to study the spatio-temporal characteristics of heat transfer under various conditions by changing the velocity ratio between the outer and inner jet, the pulsating frequency and by either applying it to the inner or outer jet.