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基于压电风扇运动规律的激光多普勒测振仪测试结果,利用动网格技术对单个垂直壁面压电风扇的三维非定常流动和传热特性进行了数值模拟,同时应用红外热像仪对表面局部对流换热系数分布进行了测量。研究结果表明:时均对流换热系数的数值模拟与实验结果具有良好的一致性;加热表面的存在,导致压电风扇激励的涡系结构与其在自由空间振动时诱导的流场存在一定的差异,脱落涡相比于自由空间时更易于破碎;压电风扇振动诱导的涡冲击加热表面所形成的近壁流动呈现出明显的平行于风扇的侧向流动,而在压电风扇两侧边则出现卷吸的特点,叶尖包络区对应的壁面局部对流换热有显著的强化作用,表面对流换热系数分布在包络区外围呈现出明显的哑铃状特征。
Based on the results of laser Doppler vibrometer test, the three-dimensional unsteady flow and heat transfer characteristics of a single vertical wall-mounted piezoelectric fan are numerically simulated by moving grid technique. At the same time, Surface local convective heat transfer coefficient distribution was measured. The results show that there is a good agreement between the numerical simulation of convective heat transfer and the experimental results. The existence of heated surface leads to a certain difference between the piezoelectric fan excited vortex system and its induced flow field in free space , Shedding vortex is more easily broken than free space; piezoelectric fan vibration-induced eddy impact heating surface formed by the near-wall flow showed a significant parallel to the lateral flow of the fan, while the piezoelectric fan on both sides of the side The characteristics of entrainment are as follows: the local convective heat transfer of the wall corresponding to the tip envelopment is significantly enhanced, and the surface convection heat transfer coefficient is obviously dumbbell shaped in the periphery of the enveloping zone.