Abstract: In order to study the efficiency of the piston/cylinder synthetic jet actuator，axisymmetric unsteady simulations were done. The results show that efficiency of the piston/cylinder synthetic jet actuator ranges from 44.9% to 67.7%，and their efficiency of electric energy ranges from 21.6% to 32.5%，which is higher than that of plasma synthetic jet actuator. With the decrease of outlet diameter or increase of frequency，the efficiency increases. However，high compression ratio has little effect on the efficiency. An auxiliary air system was adopted to improve the efficiency. With the auxiliary air system，piston work decreases，and synthetic jet kinetic energy increases，and the efficiency improves from 59.59% to 112.93%.

Key words: Piston/cylinder；Synthetic jet；Numerical simulation；Efficiency；Auxiliary air system

摘要： 为了研究活塞式合成射流激励器的效率，对所设计的一种活塞式合成射流激励器进行了轴对称非定常数值计算。研究发现，活塞式合成射流激励器的效率在44.9%~67.7%之间，其电能利用率高达21.6%~32.5%，高于电火花式合成射流激励器的电能利用率。研究表明，合成射流孔直径越小或者激励器频率越大，激励器效率越高；而压缩比较大时，压缩比对激励器效率的影响不大。另外，采用辅助进气结构，不仅能减小活塞做功，还能增大射流动能，使激励器的效率由59.59%提高到112.93%。

关键词: 活塞式；合成射流；数值模拟；效率；辅助进气系统