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    基于物理信息深度学习算法的Flame D热流场重构研究

    Reconstruction of Flame D Heat Flow Field Based on Physical Information Deep Learning Algorithm

    • 摘要: 尽管数值模拟方法在求解流体动力学的湍流过程中发展迅速,但处理复杂的几何形状和流动过程时,在准确建模和计算速度等问题上仍面临挑战性。针对当前在计算流体力学(Computational Fluid Dynamics,CFD)上存在的计算代价大等问题,本文在传统的湍流数值模拟技术的基础上,结合机器学习,以经典的Sandia Flame D燃烧模型为例,通过引入物理信息的深度学习算法,建立物理信息神经网络架构(Physical-Information Neural Network,PINN),将符合规律的物理信息内嵌到神经网络,使得用小样本就能实现参数的流场重构。在平面维度上,分别对PINN和数据驱动方法重构的结果,与CFD软件仿真结果进行对比分析,其中PINN方法在训练集大小不及样本点总数一半的情况下,即可得到数据驱动方法在大样本情况下的重构结果,重构出燃烧过程在t=1 s时刻的轴向、径向速度以及温度的L2相对误差分别为0.187%、1.194%,0.071%,且在训练集占样本点总数的55%、70%、82%的情况下,PINN方法均比数据驱动方法误差小。在时间维度上,成功重构t=0.3、0.5、1 s时刻的轴向速度云图,证明PINN方法能够重构出几何模型采样时间范围内任意时刻的物理场分布云图。

       

      Abstract: Although numerical simulation methods have developed rapidly in solving turbulent processes in fluid dynamics, there are still challenges in accurately modeling and computing speed when dealing with complex geometric shapes and flow processes. In response to the current high computational cost issues in Computational Fluid Dynamics (CFD), this paper combines traditional turbulence numerical simulation techniques with the machine learning. Taking the classic Sandia Flame D combustion model as an example, by introducing deep learning algorithms of physical information, a Physical Information Neural Network (PINN) architecture is established. The physical information that conforms to the rules is embedded into the neural network, so that parameter flow field reconstruction can be achieved with small samples. On the plane dimension, the reconstruction results of PINN and data-driven methods were compared and analyzed with the simulation results of CFD software. The PINN method can obtain the reconstruction results of data-driven methods in large sample situations when the training set size is less than half of the total number of sample points. The L2 relative errors of the reconstructed axial and radial velocities and temperatures of the combustion process at t=1 s were 0.187%, 1.194%, and 0.071%, respectively. Moreover, when the training set accounts for 55%, 70%, and 82% of the total number of sample points, the PINN method has smaller errors than data-driven methods. In terms of time dimension, the axial velocity cloud maps at t=0.3 s, 0.5 s, and 1 s were successfully reconstructed, proving that the PINN method can reconstruct the physical field distribution cloud map at any time within the sampling time range of the geometric model.

       

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