内直外旋气液同轴式喷嘴流量及雾化特性

Flow Rate and Spray Characteristics of Gas Centered

关键词:  气液同轴式喷嘴  流量特性  喷雾特性

Key words:  Gas-liquid coaxial injector  Flow rate  Spray characteristics

摘要:

针对气体中心直流、液体涡流器离心式内缩进气液同轴喷嘴，采用高速摄影和PDPA测量了其流量和雾化特性。发现在常温常压下，喷嘴流量近似与喷注压降的0.477次方成正比。喷嘴喷雾场为空心锥形，雾化角约为[110°]，随液体压降增加，雾化锥角增大。液体压降不变，雾化锥角受中心气体卷吸作用随气体压降增加而减小。液膜破碎距离与雾化锥角有关，雾化锥角越大，液膜破碎距离越短，反之亦然。随径向距离增加，雾化液滴轴向速度、径向速度减小，SMD先增大然后略有减小，沿径向呈“马鞍”状双峰分布；随轴向距离增加，粒子轴向速度减小，SMD减小。

Abstract:

To study the flow rate and spray characteristics of the gas-liquid recess coaxial injector，which consists of the gas-centered orifice injector and the liquid swirl injector，High-speed Photography Technique and Phase Doppler Particle Analyzer (PDPA) were used. At?normal temperature and pressure，the flux?is proportional to the pressure drop to the power of 0.477 nearly. The spray field is a hollow cone with a fixed spray angle，approximately，[110°]. The spray angle becomes bigger with the pressure drop of the liquid propellant bigger. In the case of the fixed pressure drop of the liquid propellant，the spray angle is affected by the gas and it declines due to the entrainment. The breakup length is related to the spray angle and it decreases when the angle increases and vice versa. In the case of fixed axial length away from the outlet of the injector，the axial and radial speed of the particles decline while the radial length rises. Additionally，with the radial length increasing，the Sauter Mean Diameter becomes bigger，followed by little decrease. The distribution shape of SMD along the radial direction has two peaks，as a saddle. In the case of the fixed radial length，the axial speed and SMD go down when the axial length goes up.