代数亚格子湍动能模型及非黏性亚格子应力模型在喷雾大涡模拟中的应用

Application of Algebraic Model for Subgrid Turbulent Kinetic Energy and Non-Viscosity Subgrid Model to Large Eddy Simulation of Fuel Spray

在KIVA3V中将考虑简化的代数亚格子湍动能模型的3种亚格子尺度模型和K方程湍动能模型的非黏性亚格子应力模型纳入程序中,对定容弹中柴油的喷射和雾化过程进行了数值研究.以燃油液相和蒸气相分布的试验数据为依据,揭示了代数亚格子尺度湍动能模型对燃油喷雾计算结果的影响,并且与K方程亚格子湍动能模型进行了对比,同时分析了加入的非黏性亚格子应力张量模型的适用性.结果显示3种亚格子应力模型及代数亚格子湍动能模型的组合可以有效地模拟流场中湍动能变化对液滴弥散速度的影响,从而使液相贯穿距及液相和气相浓度分布与试验结果更为接近.同时,该代数模型所计算的亚格子尺度湍动能与K方程模型计算结果相当吻合.非黏性亚格子模型可以计算相对准确的喷雾结果.

Three sub-grid models considering an algebraic model for the sub-grid turbulent kinetic energy and non-viscosity sub-grid model with K-equation turbulent kinetic energy model were implemented into the KIVA3V code to investigate the atomization and evaporation processes of diesel spray in a constant volume vessel.Based on the experimental results of the liquid and vapor phase distributions as well as the results obtained by the differential sub-grid scale kinetic energy（K-equation）model,this paper reveals the influence of the algebraic sub-grid turbulent kinetic energy model and non-viscosity sub-grid model on the prediction of fuel spray.Computational results show that by combining the three algebraic sub-grid models and the algebraic sub-grid turbulent energy model,the turbulent diffusion of droplets can be reasonably simulated.The liquid penetration and the predicted liquid and fuel vapor mass fraction contours are close to the experimental results.The turbulent kinetic energy given by the DSM model is in agreement with the results by the K-equation model.The added non-viscosity model accurately predicts the experimental results.