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    一种基于冷扩散模型的复杂反应流场建模方法

    A Modeling Method for Complex Turbulent Reactive Flow Field Based on Cold Diffusion Model

    • 摘要: 仿真复杂湍流反应流场的计算消耗巨大,为了缓解计算负担,许多研究基于深度学习方法构建数据驱动代理模型,但获取该代理模型所需要的数据仍存在一定困难。为了解决上述问题,本文提出一种基于冷扩散模型(Cold Diffusion Model,CDM)的代理模型。与去噪扩散概率模型(Denoising Diffusion Probabilistic Model,DDPM)不同,插值冷扩散模型在扩散过程中采用逐步插值替代加入随机高斯噪声,为复原过程引入更多信息。二维甲烷燃烧仿真实验结果表明,相比其他代理模型,插值冷扩散模型能够利用有限的数据,学习到更多的信息,减少训练所需的计算数据量,从而缓解计算负担。

       

      Abstract: Many data-driven surrogate models have been proposed to alleviate the computational burden of computational fluid dynamics (CFD) simulations. However, an adequate amount of training data is required for building data-driven surrogate models. Due to the huge consumption of simulation calculations, it is difficult to obtain the data required for training surrogate model. To remove the obstacle, this paper proposes an Interpolation Cold Diffusion Model (ICDM)-based data-driven surrogate modeling approach that only uses limited amount of CFD simulation data. The proposed method transforms the prediction of the species mass fraction distributions using boundary conditions into an image-to-image translation task, which translates the source domain species mass fraction distributions to the target domain species mass fraction distributions according to the target domain boundary conditions. Different from the original Denoising Diffusion Probabilistic Model (DDPM) that adds random Gaussian noise, ICDM interpolates between distributions in diffusion process, which can provide more information for reducing the needed amount of the training data. The proposed approach is demonstrated via 2D methane combustion experiment simulated by the CFD. By the training in 40 data points, this model produces overall normalized mean absolute errors of 1.89% for CH4 mass fraction, which is even better than some models constructed by other generation models with 800 data points, and 7 times faster than CFD model. The proposed approach can utilize only a small amount of training data, quickly building an accurate and computationally cheaper CFD surrogate model, providing a basis for deploying virtual sensors, visualizing internal reaction processes, conducting rapid reaction analysis, and exploring the optimization of reaction processes.

       

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