3D打印与机械加工喷嘴的雾化特性对比研究

为清楚阐明3D打印技术是否可应用于加工火箭发动机的关键部件——喷嘴,及加工方式会对推进剂的流动雾化产生何种影响,对相同结构的机械加工喷嘴与3D打印喷嘴的喷雾特性进行了冷态试验对比研究。基于背景光成像技术采用高速相机获得瞬态的喷雾图像,以及激光散射技术采用马尔文测量液滴粒径尺寸分布。研究发现:机械加工喷嘴同轴度普遍较差,喷嘴重复性较低,喷雾存在偏斜、分散等喷雾空间分布不均问题;3D打印喷嘴表面粗糙度较高,使得喷嘴流量系数比设计值低3%左右;在喷嘴同轴度较好的前提下,加工方式对雾化锥角及雾化粒径影响较小。

Comparative study on atomization characteristics between 3 D printing and machined injectors

In order to clarify whether 3D printing technology can be applied to machine the injector which is a critical component of the rocket engine,and how the processing method affects the flow and atomization characteristics,the cold spray experiments were conducted using the 3D printing and machined injectors with the same structure.A back-lighting photography technique has been employed to capture the instantaneous spray images with a high speed camera.The droplet size distribution was measured using Malvern based on the laser scattering technique.The results show that the coaxiality and repeatability of the machined injectors is generally poor,and the spray has the problem of uneven spatial distribution such as deflection and dispersion.While for the 3D printing injectors,the discharge coefficient is lower than the designed value by 3%due to its higher roughness.On the premise of the better injector coaxiality,the processing method has less influence on the spray angle and diameter.