Abstract
The authors have reported that minichannel flow system had high heat transfer coefficient. We investigated experimentally and numerically the heat transfer and flow structure of single and array minichannel combined with impingement flow system. The diameter D of the channel was 1.27 mm and length to diameter ratio L/D was 5. The minichannel array was so called shower head which was constructed by 19 minichannels located at the apex of equilateral triangle, the side length S of which was 4 mm. The mechanism of high heat transfer was studied numerically by the Reynolds averaged Navier-Stokes equation and k-co turbulence model. The limiting streamline pattern was correlated well to the surface heat flux distribution. The high heat transfer in the single minichannel was achieved by suppressing the development of boundary layer under strong pressure gradient near the channel inlet and by the formation of large recirculating flow system in the downstream plenum of the minichannel exit. These heat transfer mechanisms became dominant when the channel size fallen into the regime of minichannel. The heat transfer performance of minichannel array was equivalent to that of impingement jet.
