基于VOF模型的凝胶推进剂的伪流动研究

摘要

In order to study the characteristics of spurious currents considering surface tension in the two-phase flow for gel propellant primary-atomization,an incompressible fluid solver was developed based on synchronous overlap-add (SOLA)staggered mesh.Based on the gel propellant droplet,the spurious currents of VOF method was investigated.The results indicate that the numerical solution using this method agrees well with the analytical solution,and the relevant error is within 5％.Surface tension coefficient is taken into account in the definition of the strength of spurious currents,which partly eliminates the effect of the errors of surface tension of gel propellant on spurious currents values.The four mesh scales has nearly similar trends and time-average values of spurious currents,which reveals little effect of mesh scale on spurious currents.Spurious currents improves with the increase of the index n,and the growth rate is greater when n＞0.6.The values of spurious currents linearly varies with the index K,and the proportionality coefficient was 0.05.%利用VOF模型计算凝胶推进剂一次雾化的两相流动时,为研究引入表面张力后伪流动的特征,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.以凝胶推进剂液滴为对象,研究了VOF模型下的伪流动.结果表明:使用本方法的验证算例中数值解和解析解吻合度较高,误差在5％以内;伪流动强度定义中包含表面张力系数,一定程度上抵消了凝胶推进剂表面张力计算误差增大对伪流动强度的影响;4种网格尺度下,伪流动强度的变化趋势及时间平均值基本一致,说明网格尺度对伪流动无影响;伪流动强度随着本构参数n的升高而增强,并且当n＞0.6时上升得更快;伪流动强度与本构参数K呈比例系数为0.05的线性关系.