附壁振荡液气射流泵工作性能试验研究

Experimental study on performance of liquid jet gas pump by utilizing wall-attached fluidic oscillator

提出一种新的射流工作形式应用于液气射流泵,该射流形式——附壁振荡射流由射流元件产生.在液气射流泵垂直安装的试验装置上,对24种不同尺寸模型泵进行了振荡射流性能试验,并与直射情况对比.试验结果表明,工作水压力对性能影响明显,泵的性能线具有相近的最大压力比h值,随工作水压力的增大,最大流量比q和泵效率η增大.在相同工作压力下,随面积比m的增大,性能线由陡峭变为平缓,也即最大压力比减小,最大流量比增大,此时泵效率增大后减小,因此存在最优m值使效率最高.与直射情况对比,振荡射流形式获得的最大效率约为16%,小于直射情况,但两者具有相近的吸气量,采用振荡射流方式具有增大面积比的作用,随射流振荡频率的增大,压力比增大但小于直射情况.在给定具体工作压力为300 kPa情况下,由试验数据拟合出非稳定液气射流泵性能方程式,用于指导液气射流泵的实际应用.

A new kind of jet,which is a wall-attached oscillating jet produced by a fluidic element,was put forward and is going to be used in a liquid jet gas pump（LJGP）.The liquid jet gas pump was vertically installed on a test-rig,and then the performance of twenty-four test models with various dimensions was measured and compared with that of the pump with an ordinary straight jet.The results showed that the driving pressure has a significant influence on the performance,but the performance curves exhibit a similar peak pressure ratio h,the maximum flow ratio q and the pump best efficiency η increase with increasing driving pressure.At the same working pressure,the performance curves get more flat as the area ratio of throat to nozzlem is increased,namely,the peak h decreases and the maximum q increases,and the efficiency η gets a maximum at some value of m.This indicates that there is an optimum area ratio m at which the pump has the best efficiency.The best efficiency of a gas pump with an oscillating liquid jet was about 16%,less than that with a normal straight jet,but the two pumps have an approximate gas flow rate suctioned.Note that an oscillating jet needs a larger area ratio m,moreover as the oscillating frequency is increased,the pressure ratio his improved but still less than the straight jet.At the given working pressure of 300 kPa,an empirical equation for the unsteady performance curve of a LJGP was proposed by best fitting experimental data.The equation might be used to guide the practical application for such a pump.