3D打印骨架增强石蜡燃料燃烧机理实验研究

Experimental Study on Combustion Mechanism of 3D Printing Skeleton Enhanced Paraffin Fuel

关键词:  石蜡燃料  3D打印聚合物骨架  旋流燃烧  扩散燃烧  固-液混合火箭发动机

Key words:  Paraffin-based fuel  3D printed polymer skeleton  Swirling combustion  Diffusion combustion  Hybrid rocket motor

摘要:

针对固-液混合火箭发动机中石蜡基固体燃料机械性能差的问题，使用3D打印聚合物骨架镶嵌石蜡的方法增强了石蜡基燃料的结构强度，分析了骨架增强石蜡燃料在直/旋流喷注下的燃烧机理。通过对七种骨架材料进行SEM扫描、力学、热力学分析和纯氧条件下的燃烧试验，获得了不同骨架材料的微观表面结构、机械性能、热分解性能以及在纯氧环境下的燃烧性能；使用直/旋流固-气掺混燃烧试验系统，开展了螺旋型和六角型骨架增强石蜡燃料的燃烧试验，并与ABS固体燃料进行了对比。结果显示，在多种骨架材料中，ABS材料加工性能、机械性能及热分解性能良好；燃烧过程中，骨架增强石蜡燃料结构稳定性良好，石蜡液滴主要出现在石蜡-骨架交界处；旋流喷注和螺旋型骨架可促进石蜡液滴的夹带现象；在直流喷注工况中，骨架的凹槽结构增加了燃料与氧化剂的接触面积，尾部骨架结构具有稳焰作用，可促进后燃烧室的掺混燃烧；石蜡燃料和骨架燃速差异较大，发动机内弹道性能可能受此影响。

Abstract:

Aiming at the issues of poor mechanical properties of paraffin-based fuel grains in hybrid rocket motors， the method of embedding 3D printing polymer skeleton into paraffin-wax was used to enhance the structural strength of paraffin-based fuel grains. The influence mechanism of direct flow/swirl injection on the combustion performance of 3D printing skeleton enhanced paraffin fuel was investigated. First， through SEM， mechanical performance test， thermodynamic analysis and combustion test under pure oxygen conditions of seven types of skeleton materials， their microscopic surface structure， mechanical properties， thermal decomposition performance and combustion performance are obtained. Then， using the direct flow and swirling solid-gaseous hybrid combustor system， combustion experiments of the helical and hexagonal skeleton enhanced paraffin fuel grain were carried out and compared with the ABS grain. The results show that among a variety of skeleton materials， ABS material has good processing properties， mechanical properties and thermal decomposition properties. During the combustion process， skeleton enhanced paraffin fuel grain has good structural stability， and the paraffin droplets mainly appeared at the paraffin-skeleton junction. Swirl injection and spiral skeleton promote the phenomenon of paraffin droplet entrainment. In direct flow condition， the groove structure of skeleton increases the contact area between the fuel and the oxidizer， and the tail skeleton has a flame stabilizing effect， which can promote the combustion in the post combustion chamber. The regression rate of paraffin fuel and skeleton is quite different， and the internal ballistic performance of the motor may be affected by this.