航空发动机中液体燃料雾化过程十分复杂，特别是雾化初始阶段，至今无法建立准确的雾化模型。本文利用线性不稳定性分析法研究均匀气场和二维剪切气场中，不同黏性液体横向射流破碎过程。在圆柱坐标系下，建立有黏液体横向射流色散方程，利用Muller法求解得到射流表面表面波的不稳定增长率随波数的变化情况。当来流为均匀气流时，考虑液体黏性影响，射流表面扰动波增长率的减小量与增长率的比值较不考虑黏性时的至少增大1 000倍。黏性对Kelvin-Helmholtz （K-H）和Rayleigh-Taylor （R-T）不稳定性均起到削弱作用，抑制了射流破碎，且表面波波数越多，黏性对破碎的抑制作用越强，但并不影响射流的不稳定波数范围。当黏性系数增大500倍时，表面波最大增长率降低80.37%，最佳波数减小40%，黏性力对表面波的抑制作用十分明显。横向来流为二维剪切气流时，横向气动力和剪切速度促进液体射流表面波生成进而产生破碎，而液体的表面张力和黏性力则会抑制表面波生成。液气动能比越大，气流剪切作用对射流不稳定性的影响越大，K-H不稳定性主导射流表面波的生成。进一步研究液体黏性对射流不稳定性的抑制作用，发现黏性对K-H不稳定性增长率的抑制作用较R-T不稳定性大，前者不稳定性增长率的削减可达82.7%，而后者削减量为49.1%。
The two-phase flow atomization process of liquid fuels in the aero-engine is highly complicated, particularly in the initial atomization process, and the accurate primary atomization mode has not been proposed yet.This study adopts the linear instability analysis method to explore the break of different viscous liquids in uniform cross airflow and 2D shear crossflow.In the cylindrical coordinate, the viscous dispersion equation is established and the surface wave growth rate variation with the change in the wave number is calculated using the Muller method.When the incoming flow is uniform and the viscosity of the liquid jet is considered, the ratio of the reduction to the growth rate of the surface wave increases by 1 000 times compared with that under the inviscid condition.The viscosity weakens the instability of both Kelvin-Helmholtz (K-H) and Rayleigh-Taylor (R-T) and inhibits the jet break.The larger the surface wave is, the stronger the inhibition effect of viscosity on the break; however, viscosity has no effect on the unsteady wave number range of the jet.When the viscosity coefficient increases by 500 times, the maximum surface wave growth rate and the optimum wave number decrease by 80.37% and 40%, respectively, and the effect of the viscous force on the surface wave is clear.When the transverse flow is 2D shear flow, the transverse aerodynamic force and shear velocity promote the surface wave of the liquid jet growth and leads to breakup, while the surface tension and viscosity inhibit the generation of surface waves.The larger the ratio of the liquid to air kinetic energy, the stronger the influence of velocity shear effect on instability, and the K-H instability dominates the generation of the jet surface wave.Further investigation into the inhibition effect of liquid viscosity on jet instability shows that the inhibition of viscosity on the growth rate of K-H instability is larger than that on R-T instability.The reduction of instability growth rate of the former can reach 82.7%, while that of the latter is 49.1%.
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