附壁振荡射流元件频率范围的试验

Experiment of frequency range of wall attaching fluidic oscillator

对比了流量计射流元件、涡腔自激振荡射流元件和附壁振荡射流元件的结构和工作原理,其中附壁振荡射流元件具有振荡频率可调节的特点,为了将该元件应用到液气射流泵内,以振荡射流这种新的形式进行工作,对该射流元件产生的振荡射流频率范围进行了分析,由测量元件壁面压力脉动的方法获得附壁振荡频率.结果表明:射流元件在结构尺寸固定,工作压力一定时,信号水流量和信号水导管长度存在合适的范围使元件正常工作,当超出该范围时,射流元件的主射流散乱;当工作压力范围为200～450 kPa,信号水导管长度范围为300～1 000 mm,信号水流量范围为160～425 g.min-1时,获得的附壁振荡频率范围为0.8～2.7 Hz;提高附壁振荡频率方法之一是减小元件的结构尺寸.

The structure and the working principle of three types of fluidic oscillator were compared. The oscillating frequency of wall attaching fluidic oscillator is adjustable, which is different from fluidic flowmeter and self-excited oscillator. In order to apply the fluidic oscillator in liquid jet gas pump to a- chieve a new kind of jet, the oscillating frequency range produced by wail attaching fluidic oscillator was analyzed. The frequencies were obtained from experimental data of wall pressure fluctuation. For a given structure and specific working pressure of fluidic oscillator, the experimental results show that there is a suitable range for signal water flow rate and signal pipe length to keep fluidic oscillator working normally. Beyond this range, the jets of wall attaching fluidic oscillator will disperse. As the working pressure chan- ges between 200 kPa and 450 kPa, the signal pipe length varies from 300 mm to 1 000 mm with signal water flow rate range from 160 g · min 1 to 425 g · min -1 and wall attaching fluidic oscillator frequency range from 0.8 Hz to 2.7 Hz. Increasing the frequency range can decrease the oscillator structure size.