圆弧型与X型开缝翅片空气侧流动与传热特性可视化试验

利用粒子图像测速(PIV,particle image velocimetry）技术和红外热成像技术对增压空冷器空气侧的4排叉排圆弧型和X型开缝翅片的流动和传热特性进行了可视化试验研究。在试验的Reynolds数范围内，得到了阻力和换热特性曲线以及能反映流动和传热细节的流场和温度场。试验结果表明：X型开缝翅片的波动强度、流动阻力大于圆弧型开缝翅片，但前者的换热性能和场协同性优于后者。提出的新概念波动强度是表征翅片结构对流场扰动程度的物理量，波动强度越大，流场内的速度梯度、涡量强度越大，翅片结构对流场的扰动越大。可视化的试验结果为后续的数值模拟和翅片结构优化设计提供了可靠的试验依据。

Visualization experiments on air side heat transfer and fluid flow characteristics of arc-type and X-type slotted fin surfaces

Air side heat transfer and fluid flow characteristics of four-row slotted fin surfaces with arc-type and X-type strip arrangement in pressurized air cooler were studied by visualization experiments.Experiments were carried out with PIV（particle image velocimetry）system and infrared thermo tracer to visualize the flow field and the temperature distribution of two slotted fin surfaces.The experiment results showed that the fluctuation intensity and pressure drop of the X-type slotted fin surface were higher than those of the arc-type slotted fin surface.However，the heat transfer performance and field synergy property of the X-type slotted fin surface were superior to those of the arc-type fin surface.A new definition of fluctuation intensity was proposed to indicate the magnitude of flow disturbance enforced by the configuration and arrangement of slotted fin surface.The higher the fluctuation intensity，the larger the velocity gradient and the vorticity magnitude.The visualization experiment results provide a reliable experimental support for later numerical simulation and optimization design for new fin structures.