Heat transfer enhancement in micro-channel with multiple synthetic jets

A three-dimensional computational model has been developed to investigate the effect of multiple synthetic jets interaction with cross-flow in micro-channel on the cooling of microchip. Studies were performed with the use of two micro jets being in-phase and 180°out-of-phase at two different operating frequencies and a fixed diaphragm amplitude. The addition of one synthetic jet was shown to achieve greater mixing of flow in the micro-channel than those with single synthetic jet. Greater heat transfer enhancement was achieved with double synthetic jets. Results showed that greater cooling enhancement could be achieved with the out-of-phase flow configuration at oscillating frequency of 560 Hz compared with the in-phase flow configuration. However, the effect of the actuation phase at a frequency of 1120 Hz was found to be insignificant. With double synthetic jet actuators operating out-of-phase, a mere 0.1 K reduction was achieved in maximum silicon temperature compared with in-phase flow jets. The greater the mixing of flow in the micro-channel in either in-phase or out-of-phase flow configuration due to higher jets Reynolds number resulted in the constraint in further cooling enhancement despite having different phases of the flow configuration.