具有微小V肋-凹陷复合结构表面湍流传热实验研究

摘要： 通过采用瞬态液晶热像测试技术，对具有V肋-凹陷涡发生器复合结构的表面湍流流动和传热特征进行了实验研究，分析了雷诺数(Re)在10 000~60 000内具有不同肋高的V肋-凹陷阵列表面高精度传热分布，以及流阻损失特征.实验结果表明：充分发展湍流条件下的V肋-凹陷结构表面传热性能是光滑通道传热性能的1.98~2.46倍，摩擦因子是后者的2.24~4.36倍；V肋-凹陷表面传热性能是球形凹陷表面传热性能的1.21~1.76倍，摩擦因子是球形凹陷的1.96~3.89倍.在Re<20 000的条件下，具有0.6和1.0 mm高的V肋复合结构表面的综合热性能比具有1.5 mm高的V肋 凹陷表面高约4.7%~12.8%；随着Re继续提高，0.6 和1.0 mm V肋-凹陷的综合换热能力逐渐降低，而1.5 mm V肋-凹陷的综合换热能力逐渐上升，且比0.6 和1.00 mm V肋-凹陷高约4.7%~8.3%.

An Experimental Study of Turbulent Flow and Heat Transfer in a Cooling Channel with Small V Rib Dimple Compound Structure

Abstract： A structured surface with small sized V ribs and dimples is a potentially high performance cooling structure used for gas turbine blades. A comparative transient liquid crystal (TLC) transient experimental study was conducted to obtain the high resolution heat transfer characteristics and pressure loss in the cooling channels with different heights of V shaped rib dimple in the Reynolds number range of 10 000 to 60 000. The results indicated that, under the condition of fully developed turbulent flow, the Nusselt number of the V shaped rib dimple is 1.98 to 2.46 times of that of the smooth flat, with a friction factor of 2.24 to 4.36 times of that of the smooth flat. The Nusselt number of the V shaped rib dimple is 1.21 to 1.76 times of that of circular dimples, with a friction factor of 1.96 to 3.89 times of that of circular dimples. Both the depth and Reynolds number of V shaped rib can influence the flow field structure. The overall thermal performance factor of the V shaped rib dimple with a depth of 0.6 and 1.0 mm is 4.7% to 12.8% higher than with a depth of 1.5 mm at a low Reynolds number (Re<20 000). With a continuous increase of the Reynolds number, the overall thermal performance of V shaped rib dimple with a depth of 0.6 and 1.0 mm depth gradually decreases, but the overall thermal performance of V shaped rib dimple with a depth of 1.5 mm gradually increases, and is 4.7% to 8.3% higher than that with the depths of 0.6 and 1.0 mm.