活塞驱动合成喷流动和传热特性

Flow and Heat Transfer Characteristics of Synthetic Jet Driven by Piston Actuator

关键词:  合成喷  冲击冷却  流动  传热

Key words:  Synthetic jet  Impinging cooling  Flow  Heat transfer

摘要:

为了揭示合成喷冲击冷却的内在机制和作用效果,采用数值计算和实验方法分别对活塞驱动合成喷的流动特征和冲击靶板的对流换热特征进行了研究。结果表明,在活塞低频往复驱动条件下,活塞往复频率和活塞振幅的加大导致合成喷的穿透距离增大。与常规连续射流冲击冷却相比,合成喷冲击作用下的靶面对流换热系数同样具有随着冲击间距增大而先逐渐增大、后逐渐衰减的变化趋势,但最佳冲击间距值却明显高于常规射流,而且合成喷对冲击靶板的作用范围有所扩大,表明合成喷具有强的夹带能力和穿透能力。

Abstract:

To explore the mechanism and efficiency of synthetic jet impingement cooling,numerical and experimental investigation on the flow and heat transfer characteristics of a synthetic jet driven by piston actuator were conducted. When the piston reciprocates at low frequency, the increase of piston reciprocate frequency or piston reciprocate scope enhances the synthetic jet penetration. Similarly to the continuous jet impingement, the convective heat transfer coefficients at the target surface impinged by the synthetic jet also take on up-down tendency varying with the jet-to-surface spacing increment. But the jet-to-surface spacing ratio for optimum cooling achievement is greater and the cooling action region is wider than the former, indicating that the synthetic jet introduces a stronger entrainment and more vigorous penetration in the surrounding fluid. 