气固两相透平内颗粒湍流扩散的Lagarange数值模拟

Lagrangian Numerical Simulation of Particle Turbulent Diffusion in a Gas-solid Two-phase Turbine

在双级跨音速燃气透平全三维黏性湍流场下,采用气固双向耦合模型分别对不同粒度的煤颗粒以及体积分数为0.903×10-4%的5～50μm分布直径混合颗粒群在叶片流道内的湍流扩散运动进行了Lagarange数值模拟,分别得到和分析了相应的运动轨迹和运动滑移。与无黏、层流、单向耦合假设条件下的数值模拟结果比较,得到了颗粒真实的运动特性,特别是在叶片根部、顶部和压力面上,颗粒与叶片撞击点的分布与实际叶片冲蚀点分布情况较为吻合,证实了叶片流道内颗粒湍流扩散特性的不可忽略性。数值模拟结果将为进一步优化气固两相透平叶片的气动设计提供更可靠的依据。

In the totally three-dimensional viscous turbulent flow field of a dual-stage transonic gas turbine a Lagrangian numerical simulation was respectively conducted of the turbulent diffusion movement of coal particles of different particle sizes and mixed coal particles of 5-50 μm distribution diameter (volume fraction=0.903×10-4%) in a blade flow path. This was accomplished with the use of a gas-solid two-way coupled model. As a result, the corresponding movement trajectories and slippage were obtained. As compared to the results of numerical simulation under the assumed condition of non-viscid, laminar flow and one-direction coupling, more realistic movement characteristics of particles were secured. It should be specially noted that at the blade pressure surface, blade root and tip the distribution of impact-point of particles with blades are in relatively good agreement with the distribution condition of actual blade impact/erosion points. This has confirmed the non-negligible effect of the turbulent diffusion characteristics of particles in the blade flow path. The results of the numerical simulation will provide a more reliable basis for furthering the optimization of the aerodynamic design of gas-solid two-phase turbine blades.