合成射流流动特性实验研究及在燃烧中的应用探讨

应用热线风速仪对合成射流激励器出口流场进行了较详细测量。实验结果表明,激励器流场可划分为2个不同的区域。在距离激励器出口10～15倍出口缝宽之前,流动具有强烈的非定常性;在此位置下游,流动特性与常规射流相似。在流向中心线上,随着向下游距离的增加,时均速度呈先增后降的趋势,湍流度则单调递减。当激励电压有效值40V、激励频率980Hz时,时均速度在15倍缝宽处达到最大,约14.2m/s,激励器出口附近湍流度近80%。在展向上,时均速度、湍流度均剧烈改变,梯度变化明显高于常规喷流。适当参数的合成射流激励可以改善扩散燃烧器出口温度分布、降低NO_x生成量。 

Experimental Investigation of Flow Characteristics of Synthetic Jet and It's Preliminary Application to Combustion

The velocity distributions of synthetic jet were measured with Hot-wire anemometer.Experimental result shows that two distinct regions exist in the flow-field created by the actuator.Close to the slot-exit,the mean centerline velocity accelerates downstream to a maximum at distance of approximately 10～15 slot-width,when signal frequency is 980 Hz and amplitude is 40 V.At streamwise distance larger than approximately 10～15 slot-width,the flow pattern changes as conventional jet.Velocity profile across the synthetic jet appears like the profile in conventional jet,but velocity gradient is much large.At the exit of combustor,excitation using synthetic jet can improve the distribution of temperature and decrease contents of NO_x.Synthetic jet is effective for active flow control purpose.