水冲压发动机多喷嘴雾化效果试验研究

Experimental study on multi-nozzle atomizationeffect of water ramjet

良好的进水状态是保证水冲压发动机高效工作的关键,进水适度雾化既易于反应,又具有穿透力,保证与燃气充分掺混燃烧。在发动机燃烧室有限空间内,多喷嘴进水相互干扰,实际雾化效果与有效射程更加复杂。基于此,分别开展了单喷嘴雾化特性与多喷嘴雾化效果试验研究。结果表明,在距离喷嘴出口60 mm处,进水雾化粒径趋于稳定;多喷嘴同时工作时,雾化液滴在中心线附近再次相互融合,使得轴向喷射距离增加,穿透能力增强,空间上延长了进水与燃气的掺混路径,有利于充分进行化学反应,但喷嘴数量过多时,会形成实心水柱,弱化进水雾化效果,进水系统应当把握好“适度”原则。在内径180 mm的发动机中,喷嘴直径为3.2 mm,供水压差为3~4 MPa工况下,周向均布5个喷嘴时,轴向喷射距离约为17 cm,雾化效果较好,有利于促进燃烧。

A good water injection status is the key to ensuring the efficient operation of the water ramjet.Moderate water atomization is necessary for both easy reaction and penetration,which makes water to combust with the gas.Especially in the limited space of the ramjet combustion chamber,multiple nozzle water injection can interfere with each other,making the actual atomization effect and effective range more complex.Based on this,experiments were conducted to study the atomization characteristics of single-nozzle and multi-nozzle.The results show that,the atomization particle size tends to stabilize at a distance of 60 mm from the nozzle outlet.When multiple nozzles work simultaneously,the atomized droplets recombine near the centerline,increasing the axial injection distance and enhancing penetration capability,extending the mixing space of water and gas,and facilitating thorough chemical reactions.However,here are too many nozzles,a solid water column may form,weakening the water atomization effect.The water injection system should adhere to the principle of“moderation”.In an ramjet with an inner diameter of 180 mm,a nozzle diameter of 3.2 mm,and a water pressure difference of 3~4 MPa,when five nozzles are evenly distributed circumferentially,the axial injection distance is approximately 17 cm,resulting in good atomization effect and promoting combustion.