结冰风洞喷嘴雾化特性研究

结冰风洞试验段中的云雾通常由安装在稳定段的喷雾系统产生。喷雾系统雾化喷嘴的性能直接关系到结冰风洞试验段平均水滴直径(MVD)、液态水含量以及云雾均匀性等关键技术指标。在喷嘴试验台上分别使用PDI(相位多普勒干涉仪)及微流量计对小粒径雾化喷嘴的平均水滴直径(MVD)及水流量进行测量,得到了结冰风洞空气辅助雾化喷嘴的流量-粒径性能包线,同时,对喷嘴的供水、供气压力及其配比和水路节流管尺寸对喷嘴雾化性能的影响进行了研究。研究结果表明:喷嘴水、气压力差的大小和范围决定了喷嘴的粒径及调节比的范围。压差越大,粒径和水流量越大,压力差范围越大,调节比越大。减小喷嘴水路节流管的直径,可以增加喷嘴工作的水、气压力差范围,扩展喷嘴的流量-粒径包络线。最终的测试结果表明,结冰风洞所使用喷嘴 MVD 范围为7~70μm,水流量调节比为11.5,其参数调节范围优于国外同类风洞所使用雾化喷嘴。

The atomization characteristics research for spray nozzle of icing wind tunne

The icing cloud inside the icing wind tunnel test section is generated by the Spray Bar System (SBS)which is located at the wind tunnel settling chamber.The icing conditions such as the icing cloud liquid water content (LWC)and the water droplet size (MVD)are deter-mined by the spray nozzle performance of SBS.In this paper,the droplet size distribution and the water flux of the small droplet spray nozzle used in the icing wind tunnel are measured on a spray testing platform by Phase Doppler Interferometer(PDI)and low flow rate flow-meter.The for-ward scattering method was used to optimize the quality of the PDI signal and the reliability of the result.The influence of the water pressure,the air pressure,their difference and the throttle pipe diameter on the atomization characteristics of the spray nozzle are investigated.The results show that:when the pressure difference between water and air increases,the MVD and water flow-mass also increases;as the diameter of throttle pipe of water is reduced from 0.4mm to 0.35mm,the range of pressure difference between water and air increases,and the coverage of the water practical size and flow mass can exactly meet the icing wind tunnel operation require-ments.The water flow-mass ratio of the spray nozzle can reach 11.5 and the droplet diameter range can vary from 7μm to 70μm,which are better than the other similar icing wind tunnel spray nozzles in the world.