火花型合成射流激励器流动特性及其激励参数数值研究

利用能量方程中的源项模拟电火花能量的输入，数值模拟了火花型合成射流激发器的流场，获得了激励器的能量蓄积、喷射和吸入过程。结果表明，电火花瞬间能量的输入产生了腔体内的高温、高压环境，从而诱发合成射流的形成；在周期性激励下，合成射流在3个周期后稳定，喷口处的速度呈现非正弦的周期性变化，射流喷射过程时间极短，吸入外界环境气体的过程时间较长，与压电式合成射流明显不同；喷口下游周期性出现的涡对强度大、卷吸能力强。在输入能量和腔体体积不变时，喷口速度随激发频率的增加，先增加后减小，存在最佳激发频率。激发频率的增加缩短了腔体内气体的冷却时间，实验时对激发频率的选取要考虑腔体的耐温能力。

Numerical study of the flow characteristics and active parameters for the sparkjet actuator

The way of using the source term in energy equation to simulate the input energy for actuator is reasonable compared with the experimental data for the sparkjet actuator. The numerical results show that the processing of energy deposition, discharge, and recovery is obtained by the way of numerical. The instance energy input can produce the condition of high pressure and temperature in the actuator, which induce the forming of synthetic jet. Under the periodic action, the velocity of synthetic jet on the nozzle is stabilized on a non-sinusoidal law after three periodic times. The characteristic of short discharge time and long recovery time is different from the piezoelectric synthetic jet. The vortices pair at the downstream of nozzle with high intensity has an ability to roll environment air. Holding the input energy and actuator volume fixedness, the velocity at nozzle is enhanced firstly then decrease with the increase of the active frequency. The recovery stage time is shorten with the increase of active frequency. So, the choice of active frequency is under consider of the temperature resistance for actuator.