供气压力对流体型超声喷嘴雾化特性及降尘效率的影响

Impact of air supply pressure on the atomization characteristics and dust removal efficiency of fluid ultrasonic nozzle

为了掌握供气压力对流体型超声雾化喷嘴雾化特性及降尘性能的影响,借助自主研发的煤矿井下喷雾降尘实验平台,对流体型超声雾化喷嘴流量、雾化特性及降尘性能进行了实测。实验所涉及的喷嘴雾化特性参数包括雾化角、射程、雾滴粒径等,降尘性能采用全尘降尘效率和呼吸性粉尘降尘效率进行评价。实验结果表明:随着供气压力的增大,喷嘴空气流量呈幂函数形式增大,而水流量呈指数函数形式下降,气液体积流量比不断增大;喷嘴雾化角和雾滴粒径随着供气压力的增大而逐渐缩小,而雾滴速度和射程则表现为随供气压力增大而逐渐增大的趋势;对于本次实验所选取的供水压力,供气压力由0.2 MPa增加至0.7 MPa,喷嘴空气流量约增加100 L/min,水流量约降低1.3 L/min,雾化角和雾滴粒径分别约减小75°和60μm,而雾滴速度和射程分别约增加7.5 m/s和210 cm。喷嘴全尘降尘效率和呼吸性粉尘降尘效率均随着供气压力的增大呈现先增加后减小的变化规律,并在某一个供气压力下获得最高值。供水压力p_(L)不同,获得最高降尘效率所对应的供气压力p_(air)亦不同,喷雾降尘效果较优的气水压力组合有1号(p_(L)=0.2 MPa,p_(air)=0.3 MPa),2号(p_(L)=0.3 MPa,p_(air)=0.4 MPa)和3号(p_(L)=0.4 MPa,p_(air)=0.5 MPa)。煤矿现场应采用以上气水压力组合,既可获得较为理想的雾滴粒径,同时能以较低的耗水量获得较高的降尘效率。

In order to understand the impact of air supply pressure on the atomization characteristics and dust removal performance of fluid ultrasonic atomizing nozzle,the flow rate,atomization characteristics and dust removal performance of fluid ultrasonic atomizing nozzle are measured by means of the self-developed atomization and dust removal experimental platform for underground coal mine.The atomization characteristic parameters of the nozzle involved in the experiment include atomization angle,range,droplet size,etc.The dust removal performance is evaluated according to full dust removal efficiency and respirable dust removal efficiency.The experimental results show that with the increase of air supply pressure,the nozzle air flow increases in the form of power function,while the water flow rate decreases in the form of exponential function,and the gas-liquid volume flow ratio increases continuously.The nozzle atomization angle and fogdrop droplet size decrease with the increase of air supply pressure,while the fogdrop velocity and range increase with the increase of air supply pressure.Under the water supply pressure selected in this experiment,the air supply pressure increases from 0.2 MPa to 0.7 MPa,the nozzle air flow increases by about 100 L/min,the water flow decreases by about 1.3 L/min,the atomization angle and the fogdrop particle size decrease by about 75°and 60μm,and the fogdrop velocity and range increase by about 7.5 m/s and 210 cm,respectively.The full dust removal efficiency and respirable dust removal efficiency of the nozzle both increase first and then decrease with the increase of air supply pressure,and reach the maximum value under a certain air supply pressure.Different water supply pressures come with different air supply pressures for obtaining the highest dust removal efficiency.The air-water pressure combination with better atomizing and dust removal effect includes No.1(p_(L)=0.2 MPa,p_(air)=0.3 MPa),No.2(p_(L)=0.3 MPa,p_(air)=0.4 MPa)and No.3(p_(L)=0.4 MPa,p_(air)=0.5 MPa).The above air-water pressure combinations should be adopted in coal mine fields,which can obtain a relatively ideal fogdrop particle size and a higher dust removal efficiency with a lower water consumption.