The nonequilibrium properties and strong spatiotemporal long-range correlations in gas-solid suspensions were analyzed systematically by discrete particle simulation in periodic domains. The effective interphase slip velocity is significantly larger than the particle terminal velocity, the particle velocity distribution function is non-Maxwellian with a high-energy tail and the solid concentration distribution function is far from the discrete Poisson distribution, all of which manifest strong deviation from the equilibrium or homogeneous state in gas-solid flow. The solid concentration, gas and solid velocities are spatiotemporally correlated and show a clear scale-dependence. More importantly, all characteristic correlation lengths scale linearly with the size of simulation domain, although the correlation length of solid concentration is much smaller than those of gas and solid velocities. On the other hand, the characteristic correlation times at first increase with increasing domain size and then seem to approach to asymptotic values. Those results indicate that the heterogeneity and spatiotemporal long-range correlations should be considered properly in continuum theory of heterogeneous gas-solid flow.

通过周期性域中的离散粒子模拟，系统地分析了气固悬浮液中的非平衡特性和强时空长程相关性。有效相间滑移速度明显大于颗粒终端速度，颗粒速度分布函数为非麦克斯韦分布函数，具有高能尾，固体浓度分布函数远离离散泊松分布，均表现出强烈的偏离气固流动的平衡或均质状态。固体浓度、气体和固体速度是时空相关的并且显示出明显的尺度依赖性。更重要的是，所有特征相关长度与模拟域的大小成线性关系，尽管固体浓度的相关长度远小于气体和固体速度的相关长度。另一方面，特征相关时间首先随着域大小的增加而增加，然后似乎接近渐近值。这些结果表明，非均质气固流连续介质理论应适当考虑非均质性和时空长程相关性。