Local Vorticity and Flow Heat Transfer Mechanism Analysis in Micro-Cylinder-Groups Based on Field Synergy Principle

Abstract

In this paper, local vorticity distribution in micro-cylinder-groups was investigated by finite volume method and the mechanism of local heat transfer around cylinders was explored by using field synergy analysis. The vorticity distribution and local heat transfer performance are different at different positions around the cylinders. In front of micro cylinders, the vorticity has a positive correlation with heat transfer coefficient, and the average field synergy angle is close to 65° with good synergy effect. The vertical and spanwise vortices are generated on the top and side positions, respectively, which are negatively correlated with the heat transfer coefficient. Affected by the end-wall and boundary layer, the vorticity behind the micro cylinders varies at different heights and the vertical vorticity appears near the root position. The vertical and spanwise vortices account for a similar proportion near the upper part of the micro cylinders, and both of them are positively correlated with heat transfer coefficient. Due to the stagnation effect, the heat transfer coefficient in the rear position has been weakened by about 40% compared with the front position.