Measurement of Turbulence and Heat Transfer Enhancement Structure of Polymer Solution Flows in Microchannel

对蛇形通道中的粘弹性流体流动进行传热和压力损失测量以及流动可视化，以评估使用此类非牛顿流体的传热增强性能。使用聚丙烯酰胺水溶液作为粘弹性流体。可视化流型表明，在粘弹性流体情况下，即使在$Re<$2. 0的条件下，也会产生非定常流动和纵向涡状二次流。与牛顿流体的情况相比，这些流动产生了显着的传热增强效果。此外，还观察到传热和压力损失特性与韦森伯格数之间存在良好的相关性。

Heat transfer and pressure loss measurements and flow visualization were carried out for viscoelastic fluid flow in a serpentine channel in order to evaluate the heat transfer enhancement performance of using such non-Newtonian fluids. Polyacrylamide water solution was used as viscoelastic fluid. The visualized flow patterns showed that unsteady flows and longitudinal vortex-like secondary flows are generated even under the condition of$ Re<$ 2. 0 in the viscoelastic fluid case. These flows produced a remarkable heat transfer enhancement effect compared to the case of Newtonian fluid. Further, a good correlation was observed between the heat transfer and pressure loss characteristics with the Weissenberg number.