燃气轮机模型燃烧室的大涡模拟

燃烧室内的燃油雾化、蒸发以及和空气进行混合过程对燃烧过程有重要影响。提出1种基于大涡模拟的数学模型来模拟燃烧室内燃料喷射、蒸发和混合过程。被空间滤波掉的亚网格尺度涡对大尺度涡的影响由求单方程SGS湍流模型进行模拟。采用拉格朗日法和蒙特卡洛技术对流场中的喷雾粒子进行采样跟踪,采样喷雾粒子在流场中作为点源项与气相进行质量、动量和能量的双向耦合。提出1个基于SGS湍流动能的双向耦合模型来模拟SGS脉动速度对喷雾粒子运动的影响以及喷雾相对SGS湍流动能的影响。通过对1个同轴模型燃烧室中的喷雾蒸发及混合过程的大涡模拟,将预测结果和试验值进行了比较,预测值和试验值吻合良好,验证了模型的可靠性。

Large Eddy Simulation of a Gas Turbine Model Combustor

Fuel atomization, evaporation and mixing with air in gas turbine combustors are vital to the subsequent combustion process. Numerical formulation based on large eddy simulation is proposed to model fuel injection, evaporation and mixing in a gas turbine combustor. The proposed model adopts a one-equation subgrid scale turbulent model to handle the effect of the filtered subgrid scale eddies on the solved large scale eddies. Spray droplets are tracked using both Lagrangian method and Mento Carlo technique, and the sampled spray particles are regarded as point sources to conduct two-way couplings of mass, momentum and energy. The two-way coupling model based on SGS turbulent kinetic energy is used to model the mutual influences between SGS fluctuating velocity and the movement of spray droplets. The proposed models are validated against a large simulation of a co-axial model combustor and the predictions are compared to the experimental data. Good agreements are obtained, which demonstrate the reliability of the proposed models.