PIV流动测量用于平滑和90度直角带肋壁面双程方形腔体中热传递特性研究
Particle image velocimetry (PIV) experiments have been carried out to study the correlation between the high-Reynolds number turbulent flow and wall heat transfer characteristics in a two-pass square channel with a smooth walland a 90 rib-roughened wall. Detailed averaged velocity distributions and turbulent kinetic energy for both the mainand the secondary flows are given for a representative Reynolds number (Re) of 30,000. The PIV measurement resultswere compared with the heat transfer experimental data of Ekkad and Han [International Journal of Heat MassTransfer 40 (11) (1997) 2525–2537]. The result shows that the flow impingement is the primary factor for the two-passsquare channel heat transfer enhancement rather than the flow turbulence level itself. The characteristics of the secondaryflow,for example,vortex’s shape, strength,rotating-direction and positions, are closely correlated with the wallheat transfer enhancements for both smooth and ribbed wall two-pass square channels. The rib-induced flow turbulenceincreases the heat transfer mainly because of the enhanced local flow impingement near the rib.