基于锥形喷注器的凝胶推进剂流变特性数值研究

Numerical Studies on Rheological Characteristics of Gel Propellant with Regard to Tapered Injectors

关键词:  凝胶推进剂  锥形喷注器  流变特性  表观粘度

Key words:  Gel propellant  Tapered injectors  Rheological characteristics  Apparent viscosity

摘要:

为探讨锥形喷注器内凝胶推进剂的流变特性，开发了基于同步重叠相加(SOLA)交错网格算法的非牛顿不可压流体求解器，粘性本构方程采用剪切稀化幂率模型，并采用Sicilian-Hirt部分网格法处理固壁边界，开展了凝胶推进剂流变特性历变过程的数值模拟。结果表明:构造的数值模型和处理方法是适用的，数值解与理论值有较高的吻合度，误差仅在10%以内；锥形喷注器可有效加剧凝胶推进剂的剪切“稀化”作用，平均表观粘性可降低近70%；细圆管段的存在会不利于“稀化”；随着收敛角度的增大，喷注器出口截面的平均表观粘度会随之降低，50°时出口平均表观粘性仅为10°时的50%，但也会增加喷注器中的压力损失。

Abstract:

For the sake of rheological characteristics of gel propellant with regard to tapered injectors，an incompressible fluid solver ，in which shear-thinning Power-Law model was used in the viscosity constitutive equation，was developed based on synchronous overlap-add(SOLA) staggered mesh. Sicilian-Hirt partial cell treatment was applied to deal with the solid wall boundary. A series of simulations for the rheological process of gel propellant were implemented. Numerical results indicate that numerical model and methods are applicable，having good agreement between numerical solution and analytical solution in which relative errors are within 10%. Tapered injectors can strongly promote the shear-thinning behavior of the gel propellant，in which mean apparent viscosity can reduce by nearly 70%. On the contrary，the slim tube stage goes against the shear-thinning behavior. The mean apparent viscosity at the exits of the injectors，which at 50° is only 50% in accordance with 10° ，decreases with increasing the convergent semi-angle，unexpectedly resulting in much more pressure loss of the injectors.