A new method for selecting dimensionless relaxation time in the lattice Boltzmann model was proposed based on similarity criterion and gas true physical parameters. At the same time, the dimensionless relaxation time was modified by considering the influence of the boundary Knudsen layer. On this basis, the second-order slip boundary condition of the wall was considered, and the key parameters in the corresponding combined bounce-back/specular-reflection boundary condition were deduced to build a new model of unconventional gas microscale flow simulation based on the lattice Boltzmann method suitable for high temperatures and high pressures. The simulation results of methane gas flow driven by body force in infinite micro-channels and flow driven by inlet-outlet pressure differential in long straight channels were compared with the numerical and analytical solutions in the literature to verify the accuracy of the model, and the dimensionless relaxation time modification was formally optimized. The results show that the new model can effectively characterize the slippage effect, compression effect, gas density and the effect of boundary Knudsen layer in the micro-scale flow of unconventional natural gas. The new model can achieve a more comprehensive characterization of the real gas flow conditions and can be used as a basic model for the simulation of unconventional gas flow on the micro-nano scale.

提出了一种基于相似准则和气体真实物理参数的无序弛豫时间选择方法。同时，考虑边界Knudsen层的影响，修改了无因次松弛时间。在此基础上，考虑了壁的二阶滑移边界条件，推导了相应的反跳/镜面反射边界条件的关键参数，建立了基于非常规气体微观尺度流动模拟的新模型。点阵玻尔兹曼法适用于高温高压。将无穷微通道中的体力驱动的甲烷气体流和长直通道中的进，出口压差驱动的气体流的模拟结果与文献中的数值和解析解进行了比较，以验证模型的准确性，并且正式优化了无因次松弛时间修改。结果表明，新模型可以有效地表征非常规天然气微观流动中的滑移效应，压缩效应，气体密度和边界努森层的效应。该新模型可以实现对真实气流条件的更全面表征，并且可以用作微纳尺度上模拟非常规气流的基本模型。并正式优化了无因次松弛时间修改。结果表明，新模型可以有效地表征非常规天然气微观流动中的滑移效应，压缩效应，气体密度和边界努森层的效应。该新模型可以实现对真实气流条件的更全面表征，并且可以用作微纳尺度上模拟非常规气流的基本模型。并正式优化了无因次松弛时间修改。结果表明，新模型可以有效地表征非常规天然气微观流动中的滑移效应，压缩效应，气体密度和边界努森层的效应。该新模型可以实现对真实气流条件的更全面表征，并且可以用作微纳尺度上模拟非常规气流的基本模型。