压电驱动自耦合射流冲击冷却特性的实验

利用热线风速仪测量了二维狭缝自耦合射流的速度和湍流度变化,获得了激发器输入电压、频率对自耦合射流的影响规律,获得了激发器的最佳激励电压和频率值;并将自耦合射流应用于冲击换热,通过红外热像仪得到了不同加热功率下加热靶板对流换热系数分布。实验结果表明:(1)在冲击间距比小于20时,射流处于发展区内,冲击冷却效果较差;(2)冲击间距比大于20以后,射流完全形成并趋于稳定后,冲击靶板的换热效果较好;(3)但由于射流速度随着距离增大而衰减,换热效果在冲击间距比为80时达到最佳。 

Experimental Study on Impingement Cooling Characteristics of Synthetic Jet Flux Activated by Piezoelectricity

Hot-wire anemoscope was used to measure the velocity and the turbulence intensity of a synthetic jet activated by piezoelectric actuator with a two-dimensional slot nozzle.The influences of the various voltages and frequencies imparting to the synthetic jet actuator were investigated and the best actuating parameters were obtained.The temperature distributions and convective heat transfer coefficients on the target surface cooled by synthetic jet were measured by an infrared camera.The results show that:(1) when the jet-to-surface spacing ratio is less than 20,the synthetic jet is in the formation process and the cooling effect is worse;(2) when the jet-to-surface spacing ratio is greater than 20,the synthetic jet is steady and fully developed,the cooling effect is better;(3) when the distance is too far away from the nozzle,the velocity of the synthetic jet decreases,and the heat transfer coefficient reached the highest when the jet-to-surface spacing ratio is 80.