团聚硼粉与HTPB混合物流变特性

利用HAAKE流变仪研究了硼粉团聚方法、粒度、填充比例对B/HTPB混合物流变性能影响。结果表明,对于LiF包覆的硼粉(B/F),小颗粒的LiF增强了与HTPB预聚物的物理吸附作用,使体系的表观黏度反而大于未包覆的硼粉;采用HTPB包覆的硼粉(B/H,B/F/H)与HTPB混合物的表观黏度和屈服值远小于未处理硼粉,且随混合时间增加而保持不变。在相同填充质量下,小粒度团聚硼粉的黏度系数K值较大,n值较小,严重偏离牛顿流体。当团聚硼粉/HTPB质量比为55/45时,混合物的流动方程转变为Herschel-Bulkley方程,大粒度团聚硼粉的屈服值较小。因此,与小粒度硼粉相比,大粒度团聚硼粉与HTPB的混合物具有较好的流变性能。含大粒度团聚硼粉富燃料推进剂药浆具有良好的工艺性能,6 h内表观黏度小于1500 Pa.s,屈服值小于150 Pa。

Rheological characteristic of agglomerated boron powder with HTPB mixture

The effects of agglomerating boron powder methods,granularity of agglomerated boron powder,loading ratio of B and HTPB prepolymer on rheological property of B/HTPB mixture were investigated by HAAKE rheometer.Results show that the small LiF particles in LiF coated boron powder(B/F) enhance the physical absorption between LiF and HTPB prepolymer,which result in higher apparent viscidity of B/HTPB mixture than that of the untreated boron powder.The apparent viscidity and yield value of HTPB agglomerated boron powder(B/H and B/F/H)with HTPB mixtures are less than that of the untreated boron powder,and are fixedness with mixing time increasing.At the same loading mass,the viscosity coefficient K of small B/H with HTPB mixture is greater than that of larger particles,and the shear rate index n is less than that of large particles.When the mass ratio of B/HTPB is 55/45,the flow equation of two kinds of mixtures becomes a Herschel-Bulkley equation,and the yield value of large agglomerated boron powder is less than that of small particles.Therefore,the mixture of large agglomerated boron powder with HTPB has better rheological property than small particles.The slurry of fuel-rich propellant with large agglomerated boron powder in high solid loading has good process with the apparent viscidity less than 1 500 Pa·s and yield value less than 150 Pa.