泥沙的动水沉速及对准静水沉降法的改进

长期以来，专家们一直认为泥沙在动水中的沉速小于在静水中的沉速是由于动水中向上紊速阻碍泥沙沉降的结果。本文认为，时均向上紊速和向下紊速是相等的，紊速对泥沙沉速的影响，只有在悬沙浓度沿垂线分布存在梯度时才能反映出来，梯度越大，动水沉速减少越多。进而应用扩散理论导得泥沙动水沉速表达式，并对沉沙池计算中的准静水沉降法进行了修正，修正式的计算结果与实测资料十分吻合。本文提出的概念，为今后进一步研究泥沙的动水沉速开辟了一条新的途径。

Gas-solid flow field numerical simulation of different feeding and returning formations of flue-gas circulating fluidized bed

3D Euler double-fluid model was applied and three different feedstocks and reverts formations were simulated. By calculating and analyzing the state of gas and solid fluxion in absorber using three different methods of the feedstocks and reverts in recirculating fluidized bed, described the behavior of gas and solid through the gas-phase velocity, turbulence intensity, gas-solid sliding velocity, and density of particles. The results show that the feedstocks and reverts enters into absorption tower through two symmetrical feedings and are mixed with flue gas. Based on the respective analysis of each model and the com- parison analysis of the three models, this paper drew conclusions. The turbulence intensity of absorption tower is high, gas-solid sliding speed is big, and granule concentration near the axis is high, which has advantages for desulfurization and im- proving the utilization rate of absorbent.