A Concept of Pumpless Convective Micro/Micro Channel Cooling Technology

The sustained drive for faster and smaller micro electronic devices has led to a considerable increase in power density. The ability to effectively pump and enhance heat transfer in micro/mini channels is of immense technological importance. The micro channel heat exchanger has great advantages for high heat flux applications due to their high surface-to-volume ratio. Unfortunately, the small dimension of the micro channel leads to a large pressure drop and low Reynolds flow, which is usually associated with the low heat transfer coefficient. Therefore, forced convection micro heat exchangers require advanced micro pumping and heat transfer enhancement technologies. Using oscillatory flow to enhance the convective heat transfer coefficients in micro/mini channels is one of many new concepts and methodologies that have been proposed. In this paper, we propose a novel and simple streaming-based micro/mini channel cooling technology. The phenomenon of the flow streaming are found in zero-mean velocity oscillating flows in a wide range of channel geometries. Although there is no mass flow (zero-mean velocity) passing through the channel, the discrepancy in velocity profiles between the forward flow and backward flow causes fluid particles near the walls to drift toward one end while fluid particles near the centerline drift to the other end. We hypothesize that the unique characteristics of flow streaming could be used to achieve the convective cooling. The advantages of the streaming based convective cooling technique includes enhanced heat transfer coefficient, pumpless, and cost-effective. Preliminary results of scaling analysis and computer simulations are presented to demonstrate the potential of the stream based technology for micro cooling applications.