Features of vortex formation and heat transfer during cross flow around two cylinders

Abstract

The creation of all heat exchangers supposes the establishment of a quantitative and qualitative relationship between the flow and heat flux distribution at heat transfer surfaces. The paper presents the study’s results of the vortex flow’s structure and heat transfer near two circular cylinders. The distance between the cylinders ranged from 0.5d to 4d during the experiments (here d is the diameter of the cylinders). The vortex flow’s patterns in hydro- and wind tunnels in the Reynolds numbers’ range from 4000 to 40,000 are compared. To study heat transfer near the cylinders, gradient heat flux measurement was used. In aerodynamic experiments, both cylinders were heated with saturated steam, ensuring a constant surface temperature of the cylinder. The results showed an agreement of the flow patterns. The effect of distance and flow velocity on the flow around the second cylinder is revealed: there may be cases when the second cylinder is at rest, in other cases it fluctuates. Gradient heatmetry revealed a decrease in the level of fluctuations near the second cylinder. However, the average Nusselt number for the second cylinder is expectedly lower than for the first.