The influence of micro-blowing/suction on flow and heat transfer characteristics in a rectangular channel

This study numerically investigates the impact of micro-blowing/suction parameters on the flow and heat transfer characteristics. Different models and parameters are evaluated by energy saving rate and comprehensive performance coefficients. The numerical results indicate that micro-blowing reduces the wall friction drag, while micro-suction increases the wall friction, and the magnitude of drag reduction (or drag increase) increases with the augment of the micro-blowing/suction coefficient. The maximum drag reduction rates of the three models are 2.60%, 3.59%, and 3.83%, respectively. When micro-blowing and micro-suction are arranged at the bottom and top of the channel, respectively, or both arranged at the bottom of the channel, the Nusselt number increases by at least 69.75% and 89.45%, respectively. The arrangement of micro-blowing and micro-suction both arranged at the bottom of the channel is optimal for heat transfer and drag reduction. In addition, with the present three arrangements, energy saving in the channel flow can be achieved.