Comparative Investigation on the Cooling Effect of Swirling Impinging Jet using Experimental and Numerical Methods

The rapid miniaturization of the electronic packaging accelerated the development of air cooling technology. In this research, both experimental and numerical methods are adopted to investigate the heat transfer between the air swirling impinging jets and an iso-heat-flux simulant chip. In the experiment scheme, the simulant chip is impacted by the swirling jet which is generated by inserting twisted strips into round nozzles. In some range of flow Reynolds number, the effects of nozzle-to-plate spacement, the geometries of the nozzle and the thread intervals of the twisted strips are examined, and then the radial distributions of Nusselt numbers on the target plate are obtained. Meanwhile, the heat transfer characteristics of the swirling jet in both the stagnation region and the wall jet region are interpreted. In order to verify its heat transfer effect, the swirling jet is compared to the ordinary straight one. Afterwards, numerical simulation is also performed to study the heat transfer effect of this cooling system, in which, a simplified axisymmetric model is built. The angular velocity of the swirling jet, the flow Reynolds number, the dimension of the nozzle and the nozzle-to-plate spacings are all examined, and then the distribution of heat transfer coefficient (Nusselt number) on the simulant chip is also obtained.